A Comprehensive Analysis of the Influence of Fly Ash on the Bond Properties between Reinforcing Steel and Concrete

A Comprehensive Analysis of the Influence of Fly Ash on the Bond Properties between Reinforcing Steel and Concrete | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article A Comprehensive Analysis of the Influence of Fly Ash on the Bond Properties between Reinforcing Steel and Concrete Adnan, Ahmad Jawad This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-6337687/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract A significant contributor to CO₂ emissions is cement production, thus raising interest in fly ash being accepted as a sustainable alternative. The study attempts to quantify the variations in bond strength for 0–30% fly ash replacement, interrelate the properties of fly ash to the microstructure of the interface transition zone (ITZ), and establish the optimum replacement ratios for structural applications. The experiments were carried out on the Grade 53 OPC concrete (20 MPa target strength, 0.5 water-binder ratio) using measurements for compressive (ASTM C39), tensile (ASTM C496), and bond strengths (ASTM C900). The results found the 10% fly ash replacement optimal, enhancing compressive strength by 7.3% (23.6 MPa), tensile strength by 5% (4.2 MPa), and bond strength by 3% (13.9 MPa), attributed to pozzolanic densification of the ITZ. With greater fly ash substitutions (20–30%), compressive strength dropped 14–25% (to 19 MPa) and bond strength by 28–39% (to 9.7–11 MPa) due to unreacted fly ash diluting the binder along with very poor workability loss (slump: 0–0.9 in.). The study shows that fly ash acted as an ITZ microstructural enhancer at ≤ 10% and a performance-deteriorating agent beyond. The findings propose a 10% level of fly ash as the sustainable limit, representing an optimal balance between structural integrity and environmental efficiency. Super-plasticizers with silica fume/slag are recommended to address the workability issues associated with larger substitutions. Future work must tackle durability against exposure to chloride, carbonation, and seismic loads. This study thus far has furthered eco-considered construction by allowing fly ash use to meet engineering demands. Fly-ash Reinforcing Steel Concrete bond properties Bond strength Sustainable construction Ordinary Portland Cement Eco-friendly concrete Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 Figure 10 1. Introduction Infrastructure standards are mainly built with concrete because the world uses more than 30 billion tons per year because of its affordable pricing and structural versatility [ 1 , 2 ]. The primary component that binds concrete, called ordinary Portland cement (OPC), produces extraordinary environmental consequences. The CO₂ emissions from cement manufacturing represent between 8 and 10 percent of total worldwide emissions [ 3 – 5 ]. The incorporation of supplemental cementitious materials (SCMs) like fly ash from coal combustion serves as a way to increase cement reduction, decreasing carbon emissions while recovering industrial residue [ 6 – 9 ]. Although fly ash reduces environmental impact, it alters concrete mechanical properties and microscopic features, including compressive strength and porosity and interfacial transition zone (ITZ) characteristics [ 10 – 12 ]. The steel-concrete connection acts as a key structural component because it regulates stress transmission and failure behavior and ductile performance in reinforced concrete (RC) systems [ 13 – 15 ]. Previous researchers have studied the compressive strength and durability effects of fly ash extensively, but its influence on steel-concrete bond mechanics remains unknown, which raises questions about sustainable RC structure reliability[ 16 – 21 ]. Each physicochemical property of fly ash, including particle size, CaO content, and LOI, leads to different behaviors in ITZ properties as well as hydration rate and interface bond strength development [ 22 – 24 ]. The delayed chemical reactions of HVFA concrete containing at least 30% fly ash result in bond strength reductions up to 25% relative to OPC concrete during its early development stage, according to [ 25 , 26 ]. Bond strength performance experiences positive changes in the long term when fly ash replacement levels stay between 15 and 25% because pozzolanic reactions and improved pore structure take place[ 27 , 28 ]. The prediction of bond behavior becomes complicated by three external factors, including curing period combined with environmental exposure elements (such as chlorides and carbonation) and different bar surface types (deformed versus plain)[ 29 – 31 ]. The current design standards, including [ACI 318 along with Eurocode 2], do not specify recommendations to modify bond strength in structures with fly ash modifications; thus, researchers need to rely on empirical relationships based on OPC-based research [ 32 – 34 ]. Fly ash effects on bond performance necessitate an extensive investigation because this confirms the urgent need for bond characteristic evaluation. Research on steel-concrete bonding processes conducted previously employed pull-out tests and beam-end specimens together with splice tests as experimental approaches while finite element analysis (FEA) became the main numerical modeling method [ 35 – 37 ]. Analysis by primary researchers shows bond strength directly relates to concrete compressive strength and divides concrete cover thickness by bar diameter units [ 38 ]. Current scientific examinations of supplemental cementitious materials (SCMs), which incorporate silica fume and slag, demonstrate enhanced bond properties from ITZ refinements coupled with decreased material permeability [ 39 – 41 ]. The effects of using fly ash on bond strength are different between studies, with two groups showing either a 12–18% decline at a 40% substitution or no discernible changes at a 25% replacement level [ 42 , 43 ]. Studies have proven that fly ash can improve bond durability through its chloride-binding capability as well as its ability to refine pore structures[ 44 , 45 ]. The alteration of ITZ through fly ash use becomes visible using advanced characterization tools which comprise SEM, nanoindentation and X-ray microtomography[ 46 – 48 ]. The relationship between fly ash parameters such as loss on ignition (LOI) fineness together with the Ca/Si ratio and bond-slip behavior still needs significant development from the current stage of research [ 49 – 51 ]. Research to date mainly investigates single influencing factors such as replacement ratios without considering the joint effects of fly ash material characteristics combined with curing procedures and chemical admixtures [ 52 – 54 ]. A minimal LOI value below 6% will allow fly ash to absorb air-entraining admixtures and reduce bond capacity according to the research of [ 55 , 56 ]. Cross-study comparisons become impossible due to variations in testing protocols, which include cube against cylinder specimen shapes combined with different loading rates and bar surface conditions [ 57 – 59 ]. The evaluation of adhesive breakdown under multiple environmental conditions such as freeze-thaw cycles and chloride penetration remains limited to a few investigations[ 60 , 61 ]. This study bridges the existing research gaps through an investigation of fly ash properties obtained from different sources that include classification as Class F and Class C. Laboratory tests of bond performance through different stages of cure time between 7–28 days while exposing samples under multiple environmental conditions. Researchers developed prediction models that reveal the connection between fly ash characteristics and the strength of bonds. Low-carbon fly ash (LOI ≤ 10%) of high fineness (> 400 m²/kg) enhances bond strength measurements by 10–15% at a 30% replacement level, but high-carbon fly ash (LOI > 10%) leads to bond strength decreases of up to 25%. The study uses experimental testing to assess the bond strength performance of reinforcing steel and concrete using fly ash as a substitute in ratios ranging from 0 to 30%. The study looks at the interfacial transition zone (ITZ) microstructure to see how fly ash parameters impact bond strength via fineness and loss on ignition (LOI) attributes. The study specifies the most effective fly ash replacement amount that maintains a reasonable balance between material durability, workability, and sustainability considerations. The study looks at how different replacement levels impact mechanical qualities such as compressive, tensile, and bond strength to see if fly ash performs well as a component of cement in reinforced concrete applications. 2. Methodology 2.1 Introduction This project was aimed at studying the effect of fly ash on the bond properties between the reinforcing steel and concrete for purposes of building construction, and it was done at the Concrete Engineering Laboratory of Sarhad University, Peshawar, Pakistan. Grade 53 of Ordinary Portland Cement (OPC) was acquired from a local supplier in Peshawar for its deserved workability. As per the ASTM standards, the OPC was checked for quality before its use. Preliminary tests to assess the properties of the cement were conducted, and relevant tests conducted at the laboratory were based on sample requirements and included the standard consistency of water content and the initial and final setting times of cement, by the provisions of ASTM C187 and ASTM C191. The specific weight was done according to ASTM C188, and it indicates the weight of a cement sample by comparing it to the weight of the same volume of water. The particle distribution was then tested per ASTM C204 for the cement to get maximum output. The output showed that all of the tests done on the OPC met the requirements in the ASTM standards, thus making it available for use in the experimental works. This was achieved through quality testing of the properties of the cement as per the relevant standard for providing a reliable basis for comparing geopolymer concrete with conventional concrete based on Ordinary Portland Cement (OPC). 2.2 Research Methodology Flow Chart The study methodology is skillfully outlined in Fig. 1 , vividly illustrating the three phases. A comprehensive breakdown of the steps and techniques to complete this examination will be provided. The first phase involves the characterization of aggregates, steel reinforcement, and fly ash. This next phase encompasses the casting and curing of concrete samples according to ACI standards. The third phase involves testing to verify compressive strength and pull-out strength according to standards. 3. Materials This material section outlines the key materials used in the experimental study, assuring the clarity and rigor of our findings. These materials contain the following: 3.1 Cement The researcher chose locally sourced 53-grade Ordinary Portland Cement (OPC) because of its strength and durability, making it more favorable for high-performance concrete applications. Due to its ideal cohesive and adhesive physical properties, which augment its capacity to bond to other materials, OPC is commonly accepted for use in concrete production [ 62 – 64 ]. The cement selected conformed to ACI standards and represented quality and reliability. All standard tests were performed according to ASTM guidelines[ 65 ]. Table 1 presents the detailed properties of the cement. Table 1 Properties of cement Specimen Symbols Results LIMITS Sp. Gravity (ASTM C188) SG 3.17 3.1 to 3.25 Fineness (ASTM C184) F 91.5 > 90 Silica (ASTM C150) SiO₂ 20.9 20 to 25% Alumina(ASTM C150) Al₂O₃ 4.3 4–8% Iron Oxide(ASTM C150) Fe₂O₃ 3.3 3 to 6%. Calcium Oxide(ASTM C150) CaO 63 60 to 67% Loss on Ignition (ASTM C150) LOI 1.5 ≤ 5% Sulfur Trioxide (ASTM C150) SO₃ 2.7 < 3% Magnesium Oxide (ASTM C150) MgO 2.2 < 4% 3.2 Fly-Ash The research included locally sourced Class F fly ash content from Peshawar, Pakistan, for flying course materials. Class F fly ash is selected as a supplemental material for its pozzolanic strength and durability in hardened concrete. Unlike Class C fly ash, having a greater proportion of calcium and self-cementing properties, Class F fly ash contains high proportions of siliceous and aluminous compounds, which makes it highly effective for pozzolanic reactions in improving long-term performance. Moreover, Class F fly ash provides waste management and environmental issues through sustainable construction practices [ 66 ]. The strength and durability of hardened concrete increase when it is treated with fly ash as indicated by the data in Table 2 . Table 2 Characteristics of FA Specimens Standards Symbols Values Silica ASTM-C618 SiO₂ 64.2 Alumina ASTM-C618 Al₂O₃ 15.2 Iron Oxide ASTM-C618 Fe₂O₃ 3.3 Calcium Oxide ASTM-C618 CaO 5.4 Loss on Ignition ASTM-C618 LOI 2.3 Potassium Oxide ASTM-C618 K₂O 0.4 Magnesium Oxide ASTM-C618 MgO 1.5 3.3 Admixtures An alkaline solution consisting of sodium silicate (Na₂SiO₃) and sodium hydroxide (NaOH) was prepared to activate Class-F fly ash. Sodium hydroxide (NaOH) flakes were obtained from Khyber bazaar located in Peshawar. A sixteen molar (16M) solution of NaOH was prepared according to standard ACI 201.2R-01 by dissolving the flakes of the compound in distilled water without shaking the solution for twenty-four hours for complete dissociation with water. Sodium silicate (Na₂SiO₃) from Karkhano market Peshawar served as a soluble silica source for accelerating the polymerization. The Selection of 16M NaOH conforms to the ACI 201.2R-01 specifications and accepts pertinent findings from geopolymer concrete studies to enhance properties involving strength, durability, and workability. The degree of alkalinity is controlled by molarity such that enhanced geopolymerization is accompanied by enhanced compressive strength development. The use of 16M NaOH not only aids in practical application of geopolymer concrete products but also enhances the properties of chemical sulfate resistance. Laboratory studies suggest that the selection of 16M NaOH provides not just the most prosperous mechanical properties but also the most desirable results for long-term use in geopolymer construction, but it does slightly lower workability compared to 18M or 20M solutions. 3.4 Steel Bar The research examined deformed steel bars that fit the 16 mm (5/8 inches) nominal diameter in their bond behavior with geopolymer concrete. Deformed steel bars used for testing had a nominal tensile strength rate of 72.5 ksi (500MPa). The selection of the 16mm deformed steel bar and its practicality and relevance in structural applications assured a reliable study of bond behavior in geopolymer concrete. The 72.5-ksi (500-MPa) tensile strength is considered sufficient for standard reinforcement requirements, making a balance between structural relevance and ease of testing. The selection adds to the applicability of the findings for construction and engineering practice. 3.5 Aggregates The project obtained riverbed fine aggregate while the coarse aggregate consisted of appropriately sized crushed angular stones. This document presents the required information about aggregate components in the table shown below. Table 3 characteristic of Coarse and Fine Aggregates S. No Description References Results 1 Sp. Gravity of Fine Aggregate ASTM C128 2.6 2 Sp. Gravity of Coarse Aggregate ASTM C127 2.3 3 F.M of Fine Aggregate ASTM C136 2.33 4 F.M of Coarse Aggregate ASTM C136 3.07 4. Mixing, curing, and casting In this research, concrete mixes were ready for the presence of fine aggregate and water, coarse aggregates, and with 0, 10, 20, and 30% proportions, Type F fly ash was all the mixtures subjected to pullout test cubes and compressive strength with the use of cylinders. Mixing according to ASTM C192/C192M standards included making sure that all the materials mixed well with each other towards a homogeneous concrete mixture [ 65 ]. Specimens were cast and cured under controlled conditions. Curing was done in the first 24 hours at 25°C under a relative humidity of 60–70% per ASTM C511 to obtain good cement hydration [ 67 ]. The specimens will then be marked, de-moulded, and put into clean water for conditioning before testing as soon as curing is finished. The concrete cubes and cylinders were kept until they were ready for testing after the curing duration. Pullout test studies were performed under and concerning Aci 318 − 19 [ 68 ] for testing of bonding between steel and concrete, and compression tests were per ASTM C39/C39M-20 [ 67 ] to acquire "compressive strength." It was indeed a very systematic mode of acquiring accurate data to study the performance of concrete mixes affected by "Type F" fly ash. 5. Mix Design as Per Aci Such an "ACI" code offers indispensable parameters for the whole concrete mix design scenario as in ACI 318 [ 68 ]. Following these guidelines will ensure a long-lasting and reasonably performing scheme for your endeavor. Well, let us have a very simplified overview of the steps in concrete mix design per ACI guidelines: · Target Strength of concrete = 20 MPa or 3000 psi W/b = 0.5 W/b = Water to Binder Ratio Slump = 1.1 Inch Max Size of Aggregate = 3/4" water required for 1.1 slump would be 315 Ib/yd 3 Table 4 Calculations for mixed design Calculation Steps Details Value Cement Content Calculation Weight of Cement = Weight of Water / Water-Cement Ratio 630 lb/yd3 Weight of Water-binder 315 lb Water-binder Ratio 0.5 Coarse Aggregate Estimation Fineness Modulus of Coarse Aggregate 3.07 Vol. of Dry Robbed CA 0.5 or 0.6 Dry Robbed "U.W." of Coarse aggregate 145 lb/ft3 Oven Dry Weight of Coarse Aggregate 1957.5 lb/yd3 Fine Aggregate Content Estimation The volume of Dry Fine Aggregate 27 ft3 − 21 ft3 The volume of Fine Aggregate 6 ft Oven Dry Weight of Fine Aggregate 973.44 lb/yd3 Total Batch Estimation per yd³ Water-binder Volume 5.05 cft Cement Volume 3.256 cft Coarse Aggregate Volume 11.0 cft Total Volume 21 cft Estimated Batch per yd³ Water-binder 315 lb Cement 630 lb Coarse Aggregate 1957.5 lb Fine Aggregate 973.44 lb Ratio Calculation Ratio of Cement 1 Ratio of Fine Aggregate 1.54 ≈ 1.5 Ratio of Coarse Aggregate 3.1 Final Ratio 1:1.54:3.1 6. Testing 6.1 Sieve Analysis In any quality determination of the particle size distribution, sieve analysis is the most important field test; it is defined it as the passing of aggregates through a logically devised series of sieves. For fine aggregates, the sieve sizes require No. 4, No. 8, No. 16, No. 30, No. 50, No. 100, and No. 200 as well as one collecting pan [ 64 ]. For coarse aggregates, the sieve sizes include No. 3, 2.5, 1.5, ¾, ½, 3/8, and ¼. Such an enormous study ensures the accurate selection of materials, which in turn helps in enhancing the quality of construction patterns significantly. The sieved aggregate is placed on top of the sieve and subjected to mechanical shaking. During this time, the particles undergo stratification according to size. After shaking the material, the next process is to weigh the remaining material on each sieve and calculate the cumulative weight distribution. The obtained information is useful in analyzing the grading of the aggregate, which is a fundamental fortification for the adequate performance of the concrete mixtures. Table 5 Grading Assessment of Fine and Coarse Aggregates Sieves # Weight Retained (gm) % retained Cumulative% passing Cumulative% Retained 3 0 0 100 0 2.5 0 0 100 0 1.5 0 0 100 0 1 0 0 100 0 3/4 269 26.9 73.1 26.9 1/2 582 58.2 14.9 85.1 3/8 121 12.1 2.8 97.2 1/4 11 1.1 1.7 98.3 Total 307.5 Fines Modulus (Fine Aggregate) = ∑Cumulative % Retained / 100 = 307.5 / 100 = 3.07 ok Sieve Analysis (Coarse Aggregate) Sieves # Weight Retained (gm) % retained Cumulative% passing Cumulative% Retained 4 0 0 100 0 8 3.2 0.64 99.36 0.64 16 8.7 1.74 97.62 2.38 25 14.18 2.836 94.784 5.216 50 178.2 35.64 59.144 40.856 100 239 47.8 11.344 88.656 200 37.12 7.424 3.92 96.08 pan 19.6 Total 233.828 Fines Modulus (Coarse Aggregate) = ∑Cumulative % Retained / 100 = 233.83 / 100 = 2.33 ok Fine aggregates must have a fineness modulus (FM) in the range of 2.3–3.1 and coarse aggregates must also have an FM value within the stated limits in order to fulfill construction requirements. Interchange of any FM value outside the prescribed range is hereby termed unsuitable for any construction work for a coarse aggregate. Since our measured FM value falls within the accepted range, it confirms that the aggregates meet the standard requirements and are thereby suitable for preparing the geopolymer concrete mix for proper workability, compaction, and structural integrity. 6.2 Workability Workability was tested during this study using the slump test as described in ASTM C143, which delineates a "Standard Test Method to Determine the Workability of Hydraulic Cement Concrete (by slump test)”[ 69 ]. In this test, a conic mold is filled with fresh concrete and removed so that the vertical settlement of the concrete can be observed. The result is a vertical measurement of slump, which is an indicator of workability for the mix. Generally, a higher slump is interpreted to indicate greater workability for easy placement and compaction, while a lower slump suggests a stiffer mix needing more effort to work with. The results of the slump tests were tabulated in Table 6 ; these results were further examined to ascertain that the mix of concrete complied with the specification of the project concerning the required flow and consolidation efficiency, extremely essential factors to secure structural stability and durability. Table 6 Slump Values S.No Ratio identifications Slump in inch 1 0% Concrete with 0% Fly-Ash 1.1 2 10% Concrete with 10% Fly-Ash 0.9 3 20% Concrete with 20% Fly-Ash 0 4 30% Concrete with 30% Fly-Ash 0 6.3 Compression Test The compressive strength test was carried out to determine strength development within fly ash concrete and overall performance. Cylindrical specimens were prepared by keeping a concrete mix ratio of M20 (1:1.5:3) so that all batches remain uniform concerning material composition. It kept the uniform density in all the samples by vigorous tamping of the molds with a tamping rod. Following 24 hours of set time, the specimens were de-molded and immersed in a water tank for continued hydration at later ages. The number of complete specimens cast into cylinders was 12 for each curing period (7, 14, and 28 days) for a precise mean compressive strength result. The compressive strength test was conducted as per ASTM C39/C39M using a UTM[ 67 ]. Each specimen underwent the UTM individually, and a uniform compressive load was applied until failure. The compressive strength (𝜎𝑐) value was calculated using the expression: $$\:{\sigma\:}\text{c}=\frac{\text{P}}{A}$$ where: P = Maximum load applied (N), A = Cross-sectional area of the specimen (mm²). From test results, it shows the use of fly ash enhances the long-term compressive strength due to pozzolanic action, which increases strength with time. The compressive strength of 10% fly ash replacement is noted to be 23.6 MPa, as contained in Table 7 . The study results prove that fly ash makes concrete durable and performance-oriented, and henceforth, it seems to be a salt material for construction. Table 7 Compressive strength results at 28 days Fly-Ash Replacement(%) Compressive Strength(MPa) Compressive Strength(Psi) 0 22 3190 10 23.6 3442 20 21.5 3117.5 30 19 2755 6.4 Tensile Strength Test The tensile strength test has been done to determine how the fly ash concrete resists cracks and bond failure due to applied tension. These cylindrical specimens have been prepared using the concrete ratio of 1:1.5:3, and thus it has achieved batch uniformity in the material composition. To get the same consistency in density, concrete was compacted using a tamping rod. Specimens were de-molded after 24 hours of setting time and placed in a water tank for 28 days of continuous hydration. A total of 12 cylindrical specimens were cast to test parameterization for specific tensile strength. The splitting tensile test was carried out according to ASTM C496/C496M by a Universal Testing Machine (UTM)[ 70 ]. Loading them with the same load at the time of failure due to tensile. The tensile strength (𝜎𝑡) has been defined using the formula below: $$\:{\sigma\:}\text{t}=\frac{2P}{{\pi\:}\text{d}\text{L}}$$ Where: P = Maximum applied load (N), d = Diameter of the specimen (mm), L = Length of the specimen (mm) Results of the tests showed that the addition of fly ash improved internal cohesion, thereby making more tensile strength. The redesign of 10% replacement fly ash gains a tensile strength value of 4.2 MPa, which is 15% more than that of the control concrete sample. This was indicated to have an increase in strength when compared to 4.0 MPa. All these findings speak about using fly ash as a tool for the overall development of concrete, thus providing a way to adapt it structurally durably. Table 8 Tensile Strength results at 28 days Fly-Ash Replacement(%) Tensile Strength(MPa) Tensile Strength(Psi) 0 4 580 10 4.2 609 20 3.8 551 30 3.5 507.5 6.5 Pull-out Test The pull-out test procedure was selected to evaluate the bond between the reinforcement steel and the concrete matrix based on fly ash percentages of 0%, 10%, 20%, and 30%. The pull-out test was conducted using a hydraulically operated UTM capable of producing a pull-out force of 3000 psi concerning bond strength measurement. The sample arrangement was consolidated on a specially designed steel frame for testing, which simulated the bonding conditions in the field. The frame consisted of rigid steel with two plates, fastened with high-strength bolts. The upper plate was attached to the loading arm of the UTM, while the lower plate contained a hole to extract the embedded rebar during the actual pull-out test. The concrete specimens were thus placed in the test set-up in such a way as to guarantee uniform load application and accuracy in the measurement of bond performance during the test. Bond strength is determined as: $$\:{\tau\:}=\frac{\text{P}}{\pi\:dL}$$ where P = applied maximum load, d = diameter of the steel reinforcement bar, and L = length embedded in concrete. The results indicated that with the rise in fly ash content with a certain limit up to 10%, the bond strength exhibited a gradual increase. The control sample (0% fly ash replacement) had a bond strength value of 13.5 MPa, while 10% fly ash exhibited a marginally improved bond strength value (13.9 MPa). The 20% fly ash mix decreases in bond strength to 11 MPa. The lowest bond strength for 30% fly ash was reported at 9.7 MPa, and this was attributed to better microstructure densification leading to lower porosity and hence more adhesion. The improvement in bond strength has been attributed to the formation of CaSiH gel, which itself fills in and improves the bonding of the cement matrix and consequently enhances mechanical interlocking between concrete and steel. The reduction in micro-cracking provided further support for this stress transfer process, enabling bond behavior to be fostered. These findings suggest that fly ash in concrete will ensure structural performance in the long run while being an important alternative for minimizing environmental hazards contributed by cement-based materials. This study provides enough evidence to prove that fly ash improves bond strength (10%), and therefore it may be considered a way to increase the durability and performance of the reinforced concrete structures. Table 9 Pull-out test results Fly-Ash Replacement(%) Pull-out Strength(MPa) Pull-out Strength(Psi) 0 13.5 1957.5 10 13.9 2015.5 20 11 1595 30 9.7 1406.5 6.6 Beam End Test Bond strength testing between reinforcement steel and concrete matrix was carried out on bare beam ends on the concrete specimens with reinforcement embedded at one end. The preparation of the specimens was done at various percentages of fly ash replacement (0, 10, 20, and 30) to check how fly ash was affecting the bond performance. The test set-up consisted of a special loading frame. The use of a hydraulic universal testing machine (UTM) capable of applying a 3000 psi pulling force was employed for pullout failure. Thus, the application of load on the reinforced concrete samples was secured in the testing apparatus, making sure that it was well aligned and simulated the real bond conditions. The test apparatus consists of a rigid steel frame with two steel plates firmly bolted together with high-strength bolts. The upper steel plate is attached to the loading arm of the UTM, while the lower plate has a borehole to allow for rebar pullout during testing. The bond strength was determined from the expression: $$\:{\tau\:}=\frac{\text{P}}{\pi\:dL}$$ where P is the applied load, d is the diameter of the reinforcement bar, and L is the embedment length. As observed from the beam-end test outcome, bond strength was increased in progressive order with an increase in fly ash. The control concrete showed a bond strength of 12.0 MPa; with 10% fly ash, its bond strength became 13.5 MPa, which was only slightly higher. With 20% fly ash replacement, bond strength was observed to decrease to 11.76 MPa. The lowest bond strength recorded thus far was achieved by the mix with 30% fly ash replacement, which amounted to 9 MPa. The enhanced bonding performance due to pozzolanic activity with fly ash helps in refining the microstructure due to the formation of additional C-S-H gel, thus strengthening the interface between concrete and its reinforcement. A dense cementitious matrix reduces micro-cracking and improves stress transfer, promoting mechanical interlock. Thus, in addition to being beneficial to structure and environment, this paper shows a good solid case for increasing fly ash use as a sustainable alternative in concrete mixes since it increases bond strength. Table 10 shows the results of the test. Table 10 Results of beam end test Fly-Ash Replacement(%) Beam-End Test Strength(MPa) Beam-End Test Strength(Psi) 0 12 1740 10 13.5 1957.5 20 11.76 1705.2 30 9 1305 7. Results All cast samples of concrete mixtures were inspected using UTM to compare their structural characteristics. Furthermore, the specimens were examined by the guidelines established by the ASTM. The field study on concrete cylinders was carried out in the concrete laboratory of SUIT's Civil Engineering department in Peshawar. The following findings were obtained. 7.1 Sieve Analysis Sieve analysis of the fine and coarse aggregates serves their qualification against the engineering specifications for construction purposes. The sieve analysis was conducted to quantify the particle size distribution and gave consequent data as shown in Table 5 . The Fineness Modulus (FM), computed for the fine aggregate, was 3.07, which is within the accepted range of 2.3–3.1. This indicates a moderately well-graded profile conducive to workability and reduced interstitial voids, assuring maximum mechanical performance of concrete matrices. Well-graded fine aggregates will promote good particle packing and increase the densification, compressive strength, and durability of the composite material. The coarse aggregates have shown an FM of 2.33, which is slightly below the recommended one. Such gradation is inefficient and would, therefore, result in poor compaction, increased voids, and mismatching of structural homogeneity, which could bring down the load-bearing capacity and long-term durability of the concrete in a mature state. Since these shortcomings were noted, corrective measures were taken in the mixing with additional fractions of aggregate or in optimizing the gradation curves through the selective blending of aggregates to ensure a more uniform particle size distribution. The grain size distribution curves in Fig. 5b display the passed particle percentage of standardized sieves versus logarithmic particle measurement in both fine and coarse aggregates. The steep slope of the fine aggregate curve (sand) indicates high quantities of material smaller than 0.6 mm and between 0.6 mm and 1.18 mm while remaining coarse aggregates exceed 1.18 mm. The course aggregate curve (gravel) exhibits a progressive increase in the larger size range (> 4.75 mm) where it retains 10% of the material at the 9.5 mm sieve and releases 90% at the 19 mm sieve thus demonstrating a balanced big particle mixture. The intersection of these curves at the 4.75 mm sieve demarcates the boundary between fine and coarse fractions. The fineness modulus of fine aggregate and the nominal maximum size of coarse aggregate can be determined from this figure to verify adherence to standards like ASTM C33. A proper grading of fine aggregates should produce a smooth continuous curve while proper grading of coarse aggregates should achieve balanced distribution to minimize voids and optimize packing efficiency which leads to improved concrete properties and durability. The illustration demonstrates why correct grading remains essential to decrease cement requirements alongside segregating prevention and creating economical concrete mixes with superior performance. 7.2 Workability Test Under standard workability parameters, the concrete mixture underwent an experimental discount of the ASTM C143 slump test, designed to evaluate the consistency and placement characteristics of hydraulic cement concrete. This procedure involves placing fresh concrete in a conical mold (height: 300 mm, bottom diameter: 200 mm, top diameter: 100 mm), which is then rodded in three layers to expel any trapped air. Following a standard procedure to strip the mold, controlled subsidence of the concrete takes place; the accompanying vertical displacement is another important parameter describing the material's rheological behavior. Higher slump values indicate better fluidity and ease of placement/consolidation, while lesser slump describes a stiff matrix that requires extra energy for handling and finishing. Developmentally described in Table 6 , the experimental study aimed to quantify workability in respect to gradual fly-ash substitution (varying 0–30% fly ash by mass of cement) influence and showed that the control mix with 0% fly ash had recorded a minimum slump of 1.1 inches (2.79 cm), which is an indication of moderate workability suitable for conventional placement. Gradual replacement of fly ash exhibited an enormous slump loss: 10% fly ash replacement reduced this to almost 0.9 inches (2.29 cm) with the 20% and 30% fly ash mixes with zero slump into a non-flowable and cohesion-dominated state. This is attributed to combined synergistic effects from fly ash's high specific surface area and pozzolanic reactivity, thus increasing the demand for interstitial water, hence resulting in less free water available for flow behavior particle lubrication. Fly ash and slump share an inverse correlation as corroborated by empirical observations and confirmed in Fig. 6b. Figure 6a underlines the procedural legitimacy of slump test compliance to specification. These results are meaningful for mix optimizations from the aspect of placement, placing designs of stringent workability while maintaining mechanical performance. With this in mind, adjusting the water-cement ratio could counter the stiffening action of the fly ash, producing a mix containing a high-range water-reducing admixture, such as poly-carboxy late-based superplasticizers, or tuning the aggregate grading for enhanced particle pack density. All these enhancements represent avenues for achieving concrete's rheological behavior objectives in practice while maintaining the durability and structural integrity of the hardened concrete matrix. 7.3 Compression Test The compressive strength test of fly ash concrete was performed to assess the effect of fly ash on the mechanical performance. 150 mm diameter × 300 mm high cylindrical specimens were cast for uniformity in batch preparation, using premixed M20-grade (1:1.5:3 cement: sand: coarse aggregate) mix. The compaction was thorough with the specimens de-moulded after 24 hours and cured in a temperature-controlled water tank (23 ± 2°C) until the testing at 7, 14, and 28 days of casting. The tests were conducted according to ASTM C39/C39M using UTM, where compressive strength (𝜎𝑐) has been obtained from the formula: Peak failure load (𝑃) divided by cross-section area (𝐴) of the specimen. The 28-day compressive strength results (Table 7 , Fig. 7 b) did indicate an apparent non-linear relationship between fly ash content and strength. As for other M20-grade concrete, the control mix (0% fly ash) measured 22 MPa (3,190 psi). On replacing the control mix with 10% fly ash, the strength improved to 23.6 MPa (3,442 psi), which is a 7.3% improvement attributed to the pozzolanic reaction leading to the secondary formation of C-S-H, thereby densifying the matrix. But higher replacement percentages did not translate into higher performance, as with 20% fly ash the strength had dropped to 21.5 MPa (3,117.5 psi); while further decreasing to 19 MPa (2,755 psi) for 30% replacement. Such behavior indicates poor particle packing at these high replacement percentages, where excessive amounts of fly ash act largely as inert fillers, diluting the cement binder. The best performance was noted for 10% of the replacement, which is an indication of the suggestion that fly ash promotes latent long-term durability in terms of time for pozzolanic reactions, with larger proportions establishing the importance of informed cement-pozzolan ratios to avoid weakening the matrix. For this reason, the findings favor 10% fly ash as an environmentally friendly strength enhancement additive and cement-reducing material beyond which caution is advised; however, further optimization is warranted concerning structural applications. 7.4 Tensile Strength The splitting tensile test (ASTM C496/C496M) evaluated fly ash concrete's tensile strength in resisting crack and bond failure under tension. Cylindrical specimens were made from a batch employing a cement-sand-coarse aggregate mix ratio of 1:1.5:3 to ensure compositional consistency across batches. Specimens were tamped for uniform density, de-molded after 24 hours, and cured in a temperature-controlled water tank (23 ± 2°C) for 28 days for complete hydration. A total of twelve specimens were tested using a Universal Testing Machine (UTM), while tensile strength (σt) was calculated from the applied load, diameter, and length of the specimen using the expression σt = 2P/(πdL). The results (Table 8 , Fig. 8b) indicate that there exists a nonlinear relation between the fly ash content and the tensile strength. The plain mixture (0% fly ash) had a tensile strength in approximate terms of 4.0 MPa (580 psi), and this has been agreed upon for the M20 grade concrete. With the addition of 10% fly ash replacement, the strength improved to a maximum of 4.2 MPa (609 psi), representing a 15% improvement due to increasing internal cohesion afforded by the pozzolanic activity of fly ash, refinement of the interfacial transition zone (ITZ), and enhanced secondary calcium silicate hydrate (C-S-H) formation. But higher percentage replacement led to lower performance, i.e., bond strength at 20% replacement came down to 3.8 MPa (551 psi), while at 30% replacement, the value dropped to 3.5 MPa (507.5 psi). This was attributed to excess fly ash, acting as an inert filler, hampering the consolidation of particles to yield less effective binders, resulting in lower strength of the matrix. Results showed that fly ash serves dual purposes: to improve tensile resistance due to microstructural densification at 10% replacement that is then outdone at higher replacement levels due to lack of a full pozzolanic reaction and increased water demand. A specimen under test is shown in Fig. 8a, which has its maximum tensile strength at 10% fly ash treated graphically in Fig. 7 b. These findings drew attention to the need for optimizing the fly ash content concerning two objectives, sustainability and structural performance, as one way to achieve durability may be to replace 10% of cement with fly ash. 7.5 Pull-out Test In using the pull-out test, the interfacial bond strength between steel reinforcement and fly ash-modified concrete was intra-corporeally assessed for evaluating adhesion under axial tension. Specimen preparation adopted fly ash replacement levels of 0%, 10%, 20%, and 30% corresponding to the test on the hydraulically actuated Universal Testing Machine (UTM). It also built a steel structure that distributed the same load in a test simulation of real-life bonding conditions. The bond strength (𝜏) is calculated by the ratio of the maximum pull-out load (𝑃) to the product of the rebar circumference (π𝑑) and the embedding length (𝐿). The results revealed a non-linear relation between the content of fly ash and bond performance. The control mix (0% fly ash) yielded a reference bond strength of 13.5 MPa (1,957.5 psi). As expected, it was close to conventional reinforced concrete. In replacing 10% fly ash, bond strength improved slightly, recording 13.9 MPa (2,015.5 psi). It was, therefore, observed that because of pozzolanic activity, fly ash improved interfacial adhesion. This indicated that by secondary C-S-H gel formation, which densified the concrete matrix, porosity was reduced, and the mechanical interlock contributed to the steel-concrete interface's component. Greater fly ash replacements were associated with progressive solvent losses in bond strength (20% replacement reduced bond strength to 11.0 MPa (1,595 psi)); a 30% replacement yields the lowest value of 9.7 MPa (1,406.5 psi)). However, the low value as noted affirms the effect of strengthening at 10% substitution of fly ash on the improvement of the interfacial transition zone (ITZ) due to microstructural densification that lessens micro-cracking incidence and enhances stress transfer. Hence, in more than 10% substitution, the unreacted fly ash particles, acting as inert filler, dilute the cementitious binder and diminish the cohesive forces at the interface. Results include lower adhesion and higher interfacial slippage during load. As shown in Fig. 9b, the relationship of bond strength is parabolic, and this underlines the critical balance between the pozzolanic benefit and filler limitation of fly ash. These findings argue for a 10% fly ash substitution for optimal bond performance in reinforced concrete thus providing a sustainable measure toward reduced cement consumption while at the same time providing structural integrity. Greater replacement levels necessitate other economics like hybrid pozzolan blends or superplasticizers to cater to losses in adhesion while still ensuring compliance with engineering requirements. Thus, what the study does is to emphasize the need for calibrated application of fly ash to ensure durability and high performance in reinforced concrete systems. 7.6 Beam End Test The bond strength between fly ash-modified concrete and reinforcement steel has been further studied using a beam-end test to simulate interfacial adhesion under actual service conditions. Specimens were prepared with different levels of fly ash replacement—0%, 10%, 20%, and 30%—with steel embedded at one end. The experiment was done using a hydraulic Universal Testing Machine (UTM) made to apply pull force to samples amounting to 3,000 psi and embedded into a rigid steel frame to hold them in alignment with physically accurate pressure dynamics. The following equation was used to calculate bond strength (𝜏): 𝑃/(π𝑑𝐿). Results showed a nonlinear relationship between fly ash and bonding performance. The control mix, which was without fly ash (0%), recorded a bond strength of 12.0 MPa (1,740 psi), which would conventionally serve as the benchmark for concrete. Bond strength increased to 13.5 MPa (1,957.5 psi) when 10% fly ash was substituted, indicating a 12.5% improvement due to the pozzolanic activity of fly ash; which, in turn, enhanced the secondary formation of the calcium silicate hydrate (C-S-H) gel that densifies interfacial transition zones (ITZs), reduces porosity, and augments mechanical interlocking of steel with the concrete matrix. On the other hand, the continued increase in the percentages did not improve the values. attained 20% fly ash replacement reduced bond strength to 11.76 MPa (1705.2 psi), while using 30% replacement yielded the lowest value of 9.0 MPa (1,305 psi). The lower substitution of 10% indicates that fly ash can improve the ITZ by dense microstructures, thereby eliminating micro-cracking and increasing the efficiency of stress transfer at this point. However, any increases to the substitution above 10% would add unreacted fly ash particles acting as an inert filler in the cementitious binder, leading to the dilution of cohesive forces at the steel-concrete interface, hence causing weaker adhesion and an increased interfacial slippage when loaded. The evidence is shown in the sharply declining value at 20–30% replacement. As shown in Fig. 9b, the parabolic trend captures the kind of critical tipping point when the pozzolanic good qualities of fly ash turn to limitation as part of cement. These findings would reconfirm that replacing 10% of fly ash would be the most strategic maximum efficiency point where bond performance in reinforced concrete can be improved, offering advantages from the sustainability viewpoint because it reduces the consumption of cement. Greater substitutions would require countermeasures such as optimal gradation or the use of superplasticizers to maintain structural reliability. The work highlights the necessity for carefully calibrated use of fly ash in designing durable, high-performance concrete systems while calling for its use in green construction practices. 8. Conclusion In this research, an attempt has been made to conduct a systematic study of steel reinforcement in concrete bonding influenced by Type-F fly ash with testing as part of a larger experimental program. The most important parameters evaluated in this work to look for an optimum level of fly ash substitution will be compressive strength, tensile strength, and bond strength. ·A 10% replacement level of fly ash as partial cement replacement shows the most promising results, wherein the compressive strength of concrete is 23.6 MPa, tensile strength is 4.2 MPa and bond strength is 13.9 MPa. Further refinements occurred due to the ongoing process of pozzolanic reaction, and refinement incorporated with microstructure improved interfacial adhesion. With the increase of percentage replacement (20–30%), a gradual decrement in the set of developed mechanical properties was observed; however, the mixture with 30% replacement revealed a slump value of 0. This adverse phenomenon can be attributed to an undue increase in fly ash not affecting cement hydration and an increase in loss of cohesion between the particles. More associated with the increased bond strength attainable with a 10% blend of fly ash is the formation of a secondary C-S-H gel, which made the cementitious matrix denser and reduced the porosity at interfaces. Aggressive replacement with fly ash generated negative effects on mechanical performance and workability, paralleled with the otherwise optimal level of replacement to ensure faster development of strength while providing satisfactory durability. Such experimental findings illuminate the active role of fly ash as both pozzolanic material and microstructural densifier in support of its application in high-performance concrete. Sustainable use of fly ash as a cement substitute achieves a reduction in cement consumption, which translates to a reduction in CO₂ emissions and improves the beneficial reuse of industrial by-products. The replacement, with 10% fly ash substitution, is an effective method of producing durable high-performance concrete in line with sustainable construction and circular economy objectives across the globe. This research sets a primacy for future investigations as to how the enhancement of properties of fly ash interventions can be evaluated concerning bond properties in conventional and geopolymer concrete systems. The experimental results have been obtained using Type-F fly ash and locally available aggregates, so other combinations of materials will give different results from region to region. The tests were carried out in a laboratory, and its long-term permanence of fly ash-modified concrete under real-exposed environments requires evaluation for ingress of chlorides and freeze-thaw cycles. Replacement levels are from 0–30% fly ash, without the incorporation of a hybrid binder system that contributed to supplementary cementitious materials, like silica fume or ground granulated blast-furnace slag. Future studies would involve the synergistic uses of fly ash and other pozzolanic materials to ensure no deterioration of performance arising from prolonged exposure of fly ash cementitious composites too harsh. 9. Recommendation The following recommendations stem from experimental results to improve fly ash-modified concrete practical applications as well as future research projects. The overall recommended optimal dosage, at which about 10% of OPC is replaced with fly ash, enhances bond strength, compressive strength, and tensile strength while keeping workability within acceptable limits. Higher levels of replacements (≥ 20%) may also lead to compromise in the mechanical properties and, therefore, need to be carefully optimized through advanced mix design procedures. The loss of workability with increasing fly ash content hence warrants the use of high-range water-reducing admixtures or superplasticizers to attain the desired flow properties. Consideration should be given to adjusting the water-binder ratio and optimizing overlay gradation to minimize the stiffening effect of fly ash. Further, the mechanical and durability performance of 10% fly ash-modified concrete establishes its suitability for reinforced concrete structures, particularly for green infrastructure and high-performance applications. Further studies should evaluate its long-term durability under field conditions, including chloride ingress resistance, sulfate attack, freeze-thaw cycles, and carbonation. For promoting mechanical performance and durability, the interaction of fly ash with other SCMs such as silica fume, GGBFS, and meta-kaolin should be considered in the future. The hybrid binder systems may also counteract the strength diminution observed at high fly ash replacement, hence enhancing the sustainability benefits. In view of the possibility of carbon reduction and waste reutilization, the inclusion of fly ash should be promoted in infrastructural mega-projects and sustainable building activities. The policy frameworks should promote the use of fly ash-based concrete as a green alternative to conventional cementitious materials. Future studies need to test the structural behavior of fly ash-modified concrete on dynamic loading operations such as seismic resistance and fire performance. Long-term field studies are planned to measure durability, microstructural evolution, and service life performance in different environmental situations. Future evaluation of the effect of various curing conditions and those of accelerated aging of the mechanical and bond properties of fly ash-modified concrete is mandated. This essentially can be a guideline to optimize fly ash-based concrete for the sustainable and high-performance construction domain. Declarations Conflicts of Interest The authors of this article state that there are no conflicts of interest in this work. Author Contribution Investigations were conducted by Adnan and Ahmad Jawad, the methodology was developed by both Adnan. Writing, review, editing, and supervision were overseen by Adnan, and the Introduction and software were done by Adnan, Ahmad Jawad. The completed paper has been seen and approved by all authors. Acknowledgement The authors wish to express thanks to the Department of Civil Engineering (SUIT) from the bottom of their hearts, for their substantial support and assistance during the experimental effort. References Monteiro PJ, Miller SA, Horvath A (2017) Towards sustainable concrete. 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Annual Book of ASTM Standards. 10.1520/C0039_C0039M-18 ACI A (2019) 318 – 19 & ACI 318R-19: Building code requirements for structural concrete and commentary. American Concrete Institute, Farmington Hills, MI, USA. https://www.concrete.org/newsandevents/news/newsdetail.aspx?f=51719135 International A (2020) ASTM C143/C143M-20, Standard Test Method for Slump of Hydraulic-Cement Concrete . 10.1520/C0143_C0143M-12 ASTM A (2017) C496/C496M-17 Standard test method for splitting tensile strength of cylindrical concrete specimens. Am Soc Test Mater. 10.1520/C0496_C0496M-17 Additional Declarations No competing interests reported. Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. 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Article","associatedPublications":[],"authors":[{"id":445908653,"identity":"31bbf284-545a-42f8-b1d0-dd2dfda3beb8","order_by":0,"name":"Adnan","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA5klEQVRIiWNgGAWjYBACNjjJzHzwAZDi4SNeC3tbsgFICxvxdvGcMZNAGIIH8LGfTvvwo+yOvLlEWlrl1xw7GTYG5oePbuAznyd388yec88Md85IPnZbdlsy0GFsxsY5eJ2Uu5mBt+0w44YbaWm3JbcxA7XwsEnj1cL/djPj37bD9htu5JgVS26rJ0KLRO5mZqAtiRvOnDFj/LjtMDFa3m5mljl3OHnD8bZkacZtx3nYmAn4Rb4/dzPjm7LDthsOMx/8+HNbtT0/e/PDx/i0oABmHjBJrHIQYPxBiupRMApGwSgYMQAAUohHVDAbo1MAAAAASUVORK5CYII=","orcid":"","institution":"Sarhad University of Science and Information Technology","correspondingAuthor":true,"prefix":"","firstName":"","middleName":"","lastName":"Adnan","suffix":""},{"id":445908654,"identity":"58ededdd-70c7-4ae4-b286-7c12010ede4a","order_by":1,"name":"Ahmad Jawad","email":"","orcid":"","institution":"Sarhad University of Science and Information Technology","correspondingAuthor":false,"prefix":"","firstName":"Ahmad","middleName":"","lastName":"Jawad","suffix":""}],"badges":[],"createdAt":"2025-03-30 09:23:07","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-6337687/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-6337687/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":81100082,"identity":"83c0731a-b666-41f7-a669-6a4b1a39db30","added_by":"auto","created_at":"2025-04-22 08:38:13","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":59883,"visible":true,"origin":"","legend":"\u003cp\u003eFlow Chart\u003c/p\u003e","description":"","filename":"1.png","url":"https://assets-eu.researchsquare.com/files/rs-6337687/v1/016f84a534066facacca00fa.png"},{"id":81100087,"identity":"690d778c-587c-4d6a-b7e7-2f1ebc45d4f9","added_by":"auto","created_at":"2025-04-22 08:38:13","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":700388,"visible":true,"origin":"","legend":"\u003cp\u003e(a) Steel bar, (b) Universal testing machine\u003c/p\u003e","description":"","filename":"2.png","url":"https://assets-eu.researchsquare.com/files/rs-6337687/v1/9b12505b2136865d8dc61f4a.png"},{"id":81100075,"identity":"f0e48417-2447-4b70-959f-6d4c01576869","added_by":"auto","created_at":"2025-04-22 08:38:13","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":293508,"visible":true,"origin":"","legend":"\u003cp\u003eConcrete Specimens in Curing Tank and Molds for Strength Testing\u003c/p\u003e","description":"","filename":"3.png","url":"https://assets-eu.researchsquare.com/files/rs-6337687/v1/926d7d7cae0dc7dd72d6d53c.png"},{"id":81101957,"identity":"91858baa-da2f-40d7-9848-9748030d437a","added_by":"auto","created_at":"2025-04-22 08:54:14","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":317522,"visible":true,"origin":"","legend":"\u003cp\u003eConcrete Mix Design Composition (Per yd\u003csup\u003e3\u003c/sup\u003e)\u003c/p\u003e","description":"","filename":"4.png","url":"https://assets-eu.researchsquare.com/files/rs-6337687/v1/e6b66efc0288daa600d8718f.png"},{"id":81100089,"identity":"0673e92f-7d5e-4853-b237-8e103fe77ae5","added_by":"auto","created_at":"2025-04-22 08:38:14","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":240698,"visible":true,"origin":"","legend":"\u003cp\u003e(a) Mechanical Sieve Shaker Machine used for gradation, (b) Grain size distribution Curve\u003c/p\u003e","description":"","filename":"5.png","url":"https://assets-eu.researchsquare.com/files/rs-6337687/v1/86120479377a8905f87dbde4.png"},{"id":81100993,"identity":"31d00063-46b5-44a6-8496-820c222087ae","added_by":"auto","created_at":"2025-04-22 08:46:13","extension":"png","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":387862,"visible":true,"origin":"","legend":"\u003cp\u003e(a) Slump test, (b) Slump vs Fly-ash Graph\u003c/p\u003e","description":"","filename":"6.png","url":"https://assets-eu.researchsquare.com/files/rs-6337687/v1/086ff1f8d826cdbde077807c.png"},{"id":81100105,"identity":"3943e09b-a20b-4f91-9f20-5b66707c5b0f","added_by":"auto","created_at":"2025-04-22 08:38:14","extension":"png","order_by":7,"title":"Figure 7","display":"","copyAsset":false,"role":"figure","size":316596,"visible":true,"origin":"","legend":"\u003cp\u003eCompressive strength result-28days\u003c/p\u003e","description":"","filename":"7.png","url":"https://assets-eu.researchsquare.com/files/rs-6337687/v1/9fa27d247873da5d1bf909b6.png"},{"id":81100088,"identity":"d741a827-0d16-4c69-b273-b33d9de67b20","added_by":"auto","created_at":"2025-04-22 08:38:13","extension":"png","order_by":8,"title":"Figure 8","display":"","copyAsset":false,"role":"figure","size":342975,"visible":true,"origin":"","legend":"\u003cp\u003eFigure.7. (a) Sample of Concrete, (b) results of tensile strength\u003c/p\u003e","description":"","filename":"8.png","url":"https://assets-eu.researchsquare.com/files/rs-6337687/v1/4a3b523e269ccdcdcc61af9d.png"},{"id":81100073,"identity":"93d90c75-5053-4bb8-be7e-a239d442b2ce","added_by":"auto","created_at":"2025-04-22 08:38:13","extension":"png","order_by":9,"title":"Figure 9","display":"","copyAsset":false,"role":"figure","size":506645,"visible":true,"origin":"","legend":"\u003cp\u003eFigure 8 (a) Universal testing machine, (b) results of pull-out test\u003c/p\u003e","description":"","filename":"9.png","url":"https://assets-eu.researchsquare.com/files/rs-6337687/v1/db8871ea0f46c1ba8b008faa.png"},{"id":81100108,"identity":"d90f0dea-f3f1-44f0-b963-a44be626a328","added_by":"auto","created_at":"2025-04-22 08:38:14","extension":"png","order_by":10,"title":"Figure 10","display":"","copyAsset":false,"role":"figure","size":409177,"visible":true,"origin":"","legend":"\u003cp\u003eFigure.9. (a) A universal testing machine, (b) results of beam end test strength\u003c/p\u003e","description":"","filename":"10.png","url":"https://assets-eu.researchsquare.com/files/rs-6337687/v1/fb9d687cb6398e4840650893.png"},{"id":83574964,"identity":"97e1d607-c806-4ae5-9a72-c4afa22a56a9","added_by":"auto","created_at":"2025-05-28 18:57:16","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":5585679,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-6337687/v1/d41e97e1-c750-4cec-a6b7-99222df02980.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"A Comprehensive Analysis of the Influence of Fly Ash on the Bond Properties between Reinforcing Steel and Concrete","fulltext":[{"header":"1. Introduction","content":"\u003cp\u003eInfrastructure standards are mainly built with concrete because the world uses more than 30\u0026nbsp;billion tons per year because of its affordable pricing and structural versatility [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]. The primary component that binds concrete, called ordinary Portland cement (OPC), produces extraordinary environmental consequences. The CO₂ emissions from cement manufacturing represent between 8 and 10 percent of total worldwide emissions [\u003cspan additionalcitationids=\"CR4\" citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e]. The incorporation of supplemental cementitious materials (SCMs) like fly ash from coal combustion serves as a way to increase cement reduction, decreasing carbon emissions while recovering industrial residue [\u003cspan additionalcitationids=\"CR7 CR8\" citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]. Although fly ash reduces environmental impact, it alters concrete mechanical properties and microscopic features, including compressive strength and porosity and interfacial transition zone (ITZ) characteristics [\u003cspan additionalcitationids=\"CR11\" citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e]. The steel-concrete connection acts as a key structural component because it regulates stress transmission and failure behavior and ductile performance in reinforced concrete (RC) systems [\u003cspan additionalcitationids=\"CR14\" citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e]. Previous researchers have studied the compressive strength and durability effects of fly ash extensively, but its influence on steel-concrete bond mechanics remains unknown, which raises questions about sustainable RC structure reliability[\u003cspan additionalcitationids=\"CR17 CR18 CR19 CR20\" citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e]. Each physicochemical property of fly ash, including particle size, CaO content, and LOI, leads to different behaviors in ITZ properties as well as hydration rate and interface bond strength development [\u003cspan additionalcitationids=\"CR23\" citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e]. The delayed chemical reactions of HVFA concrete containing at least 30% fly ash result in bond strength reductions up to 25% relative to OPC concrete during its early development stage, according to [\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e, \u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e]. Bond strength performance experiences positive changes in the long term when fly ash replacement levels stay between 15 and 25% because pozzolanic reactions and improved pore structure take place[\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e, \u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e]. The prediction of bond behavior becomes complicated by three external factors, including curing period combined with environmental exposure elements (such as chlorides and carbonation) and different bar surface types (deformed versus plain)[\u003cspan additionalcitationids=\"CR30\" citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e]. The current design standards, including [ACI 318 along with Eurocode 2], do not specify recommendations to modify bond strength in structures with fly ash modifications; thus, researchers need to rely on empirical relationships based on OPC-based research [\u003cspan additionalcitationids=\"CR33\" citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e34\u003c/span\u003e]. Fly ash effects on bond performance necessitate an extensive investigation because this confirms the urgent need for bond characteristic evaluation.\u003c/p\u003e \u003cp\u003eResearch on steel-concrete bonding processes conducted previously employed pull-out tests and beam-end specimens together with splice tests as experimental approaches while finite element analysis (FEA) became the main numerical modeling method [\u003cspan additionalcitationids=\"CR36\" citationid=\"CR35\" class=\"CitationRef\"\u003e35\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR37\" class=\"CitationRef\"\u003e37\u003c/span\u003e]. Analysis by primary researchers shows bond strength directly relates to concrete compressive strength and divides concrete cover thickness by bar diameter units [\u003cspan citationid=\"CR38\" class=\"CitationRef\"\u003e38\u003c/span\u003e]. Current scientific examinations of supplemental cementitious materials (SCMs), which incorporate silica fume and slag, demonstrate enhanced bond properties from ITZ refinements coupled with decreased material permeability [\u003cspan additionalcitationids=\"CR40\" citationid=\"CR39\" class=\"CitationRef\"\u003e39\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR41\" class=\"CitationRef\"\u003e41\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eThe effects of using fly ash on bond strength are different between studies, with two groups showing either a 12\u0026ndash;18% decline at a 40% substitution or no discernible changes at a 25% replacement level [\u003cspan citationid=\"CR42\" class=\"CitationRef\"\u003e42\u003c/span\u003e, \u003cspan citationid=\"CR43\" class=\"CitationRef\"\u003e43\u003c/span\u003e]. Studies have proven that fly ash can improve bond durability through its chloride-binding capability as well as its ability to refine pore structures[\u003cspan citationid=\"CR44\" class=\"CitationRef\"\u003e44\u003c/span\u003e, \u003cspan citationid=\"CR45\" class=\"CitationRef\"\u003e45\u003c/span\u003e]. The alteration of ITZ through fly ash use becomes visible using advanced characterization tools which comprise SEM, nanoindentation and X-ray microtomography[\u003cspan additionalcitationids=\"CR47\" citationid=\"CR46\" class=\"CitationRef\"\u003e46\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR48\" class=\"CitationRef\"\u003e48\u003c/span\u003e]. The relationship between fly ash parameters such as loss on ignition (LOI) fineness together with the Ca/Si ratio and bond-slip behavior still needs significant development from the current stage of research [\u003cspan additionalcitationids=\"CR50\" citationid=\"CR49\" class=\"CitationRef\"\u003e49\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR51\" class=\"CitationRef\"\u003e51\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eResearch to date mainly investigates single influencing factors such as replacement ratios without considering the joint effects of fly ash material characteristics combined with curing procedures and chemical admixtures [\u003cspan additionalcitationids=\"CR53\" citationid=\"CR52\" class=\"CitationRef\"\u003e52\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR54\" class=\"CitationRef\"\u003e54\u003c/span\u003e]. A minimal LOI value below 6% will allow fly ash to absorb air-entraining admixtures and reduce bond capacity according to the research of [\u003cspan citationid=\"CR55\" class=\"CitationRef\"\u003e55\u003c/span\u003e, \u003cspan citationid=\"CR56\" class=\"CitationRef\"\u003e56\u003c/span\u003e]. Cross-study comparisons become impossible due to variations in testing protocols, which include cube against cylinder specimen shapes combined with different loading rates and bar surface conditions [\u003cspan additionalcitationids=\"CR58\" citationid=\"CR57\" class=\"CitationRef\"\u003e57\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR59\" class=\"CitationRef\"\u003e59\u003c/span\u003e]. The evaluation of adhesive breakdown under multiple environmental conditions such as freeze-thaw cycles and chloride penetration remains limited to a few investigations[\u003cspan citationid=\"CR60\" class=\"CitationRef\"\u003e60\u003c/span\u003e, \u003cspan citationid=\"CR61\" class=\"CitationRef\"\u003e61\u003c/span\u003e]. This study bridges the existing research gaps through an investigation of fly ash properties obtained from different sources that include classification as Class F and Class C. Laboratory tests of bond performance through different stages of cure time between 7\u0026ndash;28 days while exposing samples under multiple environmental conditions. Researchers developed prediction models that reveal the connection between fly ash characteristics and the strength of bonds. Low-carbon fly ash (LOI\u0026thinsp;\u0026le;\u0026thinsp;10%) of high fineness (\u0026gt;\u0026thinsp;400 m\u0026sup2;/kg) enhances bond strength measurements by 10\u0026ndash;15% at a 30% replacement level, but high-carbon fly ash (LOI\u0026thinsp;\u0026gt;\u0026thinsp;10%) leads to bond strength decreases of up to 25%.\u003c/p\u003e \u003cp\u003eThe study uses experimental testing to assess the bond strength performance of reinforcing steel and concrete using fly ash as a substitute in ratios ranging from 0 to 30%. The study looks at the interfacial transition zone (ITZ) microstructure to see how fly ash parameters impact bond strength via fineness and loss on ignition (LOI) attributes. The study specifies the most effective fly ash replacement amount that maintains a reasonable balance between material durability, workability, and sustainability considerations. The study looks at how different replacement levels impact mechanical qualities such as compressive, tensile, and bond strength to see if fly ash performs well as a component of cement in reinforced concrete applications.\u003c/p\u003e"},{"header":"2. Methodology","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003e2.1 Introduction\u003c/h2\u003e \u003cp\u003eThis project was aimed at studying the effect of fly ash on the bond properties between the reinforcing steel and concrete for purposes of building construction, and it was done at the Concrete Engineering Laboratory of Sarhad University, Peshawar, Pakistan. Grade 53 of Ordinary Portland Cement (OPC) was acquired from a local supplier in Peshawar for its deserved workability. As per the ASTM standards, the OPC was checked for quality before its use. Preliminary tests to assess the properties of the cement were conducted, and relevant tests conducted at the laboratory were based on sample requirements and included the standard consistency of water content and the initial and final setting times of cement, by the provisions of ASTM C187 and ASTM C191. The specific weight was done according to ASTM C188, and it indicates the weight of a cement sample by comparing it to the weight of the same volume of water. The particle distribution was then tested per ASTM C204 for the cement to get maximum output. The output showed that all of the tests done on the OPC met the requirements in the ASTM standards, thus making it available for use in the experimental works. This was achieved through quality testing of the properties of the cement as per the relevant standard for providing a reliable basis for comparing geopolymer concrete with conventional concrete based on Ordinary Portland Cement (OPC).\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec4\" class=\"Section2\"\u003e \u003ch2\u003e2.2 Research Methodology Flow Chart\u003c/h2\u003e \u003cp\u003eThe study methodology is skillfully outlined in Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e, vividly illustrating the three phases. A comprehensive breakdown of the steps and techniques to complete this examination will be provided. The first phase involves the characterization of aggregates, steel reinforcement, and fly ash. This next phase encompasses the casting and curing of concrete samples according to ACI standards. The third phase involves testing to verify compressive strength and pull-out strength according to standards.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e"},{"header":"3. Materials","content":"\u003cp\u003eThis material section outlines the key materials used in the experimental study, assuring the clarity and rigor of our findings. These materials contain the following:\u003c/p\u003e \u003cdiv id=\"Sec6\" class=\"Section2\"\u003e \u003ch2\u003e3.1 Cement\u003c/h2\u003e \u003cp\u003eThe researcher chose locally sourced 53-grade Ordinary Portland Cement (OPC) because of its strength and durability, making it more favorable for high-performance concrete applications. Due to its ideal cohesive and adhesive physical properties, which augment its capacity to bond to other materials, OPC is commonly accepted for use in concrete production [\u003cspan additionalcitationids=\"CR63\" citationid=\"CR62\" class=\"CitationRef\"\u003e62\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR64\" class=\"CitationRef\"\u003e64\u003c/span\u003e]. The cement selected conformed to ACI standards and represented quality and reliability. All standard tests were performed according to ASTM guidelines[\u003cspan citationid=\"CR65\" class=\"CitationRef\"\u003e65\u003c/span\u003e]. Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e presents the detailed properties of the cement.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eProperties of cement\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"4\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSpecimen\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eSymbols\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eResults\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eLIMITS\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSp. Gravity (ASTM C188)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eSG\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e3.17\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e3.1 to 3.25\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eFineness (ASTM C184)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eF\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e91.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u0026gt;\u0026thinsp;90\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSilica (ASTM C150)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eSiO₂\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e20.9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e20 to 25%\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAlumina(ASTM C150)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eAl₂O₃\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e4.3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e4\u0026ndash;8%\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eIron Oxide(ASTM C150)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eFe₂O₃\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e3.3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e3 to 6%.\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCalcium Oxide(ASTM C150)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eCaO\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e63\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e60 to 67%\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eLoss on Ignition (ASTM C150)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eLOI\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u0026le;\u0026thinsp;5%\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSulfur Trioxide (ASTM C150)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eSO₃\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2.7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;3%\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMagnesium Oxide (ASTM C150)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eMgO\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;4%\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec7\" class=\"Section2\"\u003e \u003ch2\u003e3.2 Fly-Ash\u003c/h2\u003e \u003cp\u003eThe research included locally sourced Class F fly ash content from Peshawar, Pakistan, for flying course materials. Class F fly ash is selected as a supplemental material for its pozzolanic strength and durability in hardened concrete. Unlike Class C fly ash, having a greater proportion of calcium and self-cementing properties, Class F fly ash contains high proportions of siliceous and aluminous compounds, which makes it highly effective for pozzolanic reactions in improving long-term performance. Moreover, Class F fly ash provides waste management and environmental issues through sustainable construction practices [\u003cspan citationid=\"CR66\" class=\"CitationRef\"\u003e66\u003c/span\u003e]. The strength and durability of hardened concrete increase when it is treated with fly ash as indicated by the data in Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab2\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eCharacteristics of FA\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"4\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSpecimens\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eStandards\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eSymbols\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eValues\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSilica\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eASTM-C618\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cb\u003eSiO₂\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e64.2\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAlumina\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eASTM-C618\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eAl₂O₃\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e15.2\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eIron Oxide\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eASTM-C618\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eFe₂O₃\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e3.3\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCalcium Oxide\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eASTM-C618\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eCaO\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e5.4\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eLoss on Ignition\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eASTM-C618\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eLOI\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e2.3\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePotassium Oxide\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eASTM-C618\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eK₂O\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.4\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMagnesium Oxide\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eASTM-C618\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eMgO\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e1.5\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec8\" class=\"Section2\"\u003e \u003ch2\u003e3.3 Admixtures\u003c/h2\u003e \u003cp\u003eAn alkaline solution consisting of sodium silicate (Na₂SiO₃) and sodium hydroxide (NaOH) was prepared to activate Class-F fly ash. Sodium hydroxide (NaOH) flakes were obtained from Khyber bazaar located in Peshawar. A sixteen molar (16M) solution of NaOH was prepared according to standard ACI 201.2R-01 by dissolving the flakes of the compound in distilled water without shaking the solution for twenty-four hours for complete dissociation with water. Sodium silicate (Na₂SiO₃) from Karkhano market Peshawar served as a soluble silica source for accelerating the polymerization.\u003c/p\u003e \u003cp\u003eThe Selection of 16M NaOH conforms to the ACI 201.2R-01 specifications and accepts pertinent findings from geopolymer concrete studies to enhance properties involving strength, durability, and workability. The degree of alkalinity is controlled by molarity such that enhanced geopolymerization is accompanied by enhanced compressive strength development. The use of 16M NaOH not only aids in practical application of geopolymer concrete products but also enhances the properties of chemical sulfate resistance. Laboratory studies suggest that the selection of 16M NaOH provides not just the most prosperous mechanical properties but also the most desirable results for long-term use in geopolymer construction, but it does slightly lower workability compared to 18M or 20M solutions.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec9\" class=\"Section2\"\u003e \u003ch2\u003e3.4 Steel Bar\u003c/h2\u003e \u003cp\u003eThe research examined deformed steel bars that fit the 16 mm (5/8 inches) nominal diameter in their bond behavior with geopolymer concrete. Deformed steel bars used for testing had a nominal tensile strength rate of 72.5 ksi (500MPa).\u003c/p\u003e \u003cp\u003eThe selection of the 16mm deformed steel bar and its practicality and relevance in structural applications assured a reliable study of bond behavior in geopolymer concrete. The 72.5-ksi (500-MPa) tensile strength is considered sufficient for standard reinforcement requirements, making a balance between structural relevance and ease of testing. The selection adds to the applicability of the findings for construction and engineering practice.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec10\" class=\"Section2\"\u003e \u003ch2\u003e3.5 Aggregates\u003c/h2\u003e \u003cp\u003eThe project obtained riverbed fine aggregate while the coarse aggregate consisted of appropriately sized crushed angular stones. This document presents the required information about aggregate components in the table shown below.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab3\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 3\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003echaracteristic of Coarse and Fine Aggregates\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"4\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eS. No\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eDescription\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eReferences\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eResults\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eSp. Gravity of Fine Aggregate\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eASTM C128\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e2.6\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eSp. Gravity of Coarse Aggregate\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eASTM C127\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e2.3\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eF.M of Fine Aggregate\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eASTM C136\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e2.33\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eF.M of Coarse Aggregate\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eASTM C136\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e3.07\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003c/div\u003e"},{"header":"4. Mixing, curing, and casting","content":"\u003cp\u003eIn this research, concrete mixes were ready for the presence of fine aggregate and water, coarse aggregates, and with 0, 10, 20, and 30% proportions, Type F fly ash was all the mixtures subjected to pullout test cubes and compressive strength with the use of cylinders. Mixing according to ASTM C192/C192M standards included making sure that all the materials mixed well with each other towards a homogeneous concrete mixture [\u003cspan citationid=\"CR65\" class=\"CitationRef\"\u003e65\u003c/span\u003e]. Specimens were cast and cured under controlled conditions. Curing was done in the first 24 hours at 25\u0026deg;C under a relative humidity of 60\u0026ndash;70% per ASTM C511 to obtain good cement hydration [\u003cspan citationid=\"CR67\" class=\"CitationRef\"\u003e67\u003c/span\u003e]. The specimens will then be marked, de-moulded, and put into clean water for conditioning before testing as soon as curing is finished. The concrete cubes and cylinders were kept until they were ready for testing after the curing duration. Pullout test studies were performed under and concerning Aci 318\u0026thinsp;\u0026minus;\u0026thinsp;19 [\u003cspan citationid=\"CR68\" class=\"CitationRef\"\u003e68\u003c/span\u003e] for testing of bonding between steel and concrete, and compression tests were per ASTM C39/C39M-20 [\u003cspan citationid=\"CR67\" class=\"CitationRef\"\u003e67\u003c/span\u003e] to acquire \"compressive strength.\" It was indeed a very systematic mode of acquiring accurate data to study the performance of concrete mixes affected by \"Type F\" fly ash.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e"},{"header":"5. Mix Design as Per Aci","content":"\u003cp\u003eSuch an \"ACI\" code offers indispensable parameters for the whole concrete mix design scenario as in ACI 318 [\u003cspan citationid=\"CR68\" class=\"CitationRef\"\u003e68\u003c/span\u003e]. Following these guidelines will ensure a long-lasting and reasonably performing scheme for your endeavor. Well, let us have a very simplified overview of the steps in concrete mix design per ACI guidelines: \u0026middot;\u003c/p\u003e \u003cp\u003e \u003cul\u003e \u003cli\u003e \u003cp\u003eTarget Strength of concrete\u0026thinsp;=\u0026thinsp;20 MPa or 3000 psi\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003eW/b\u0026thinsp;=\u0026thinsp;0.5\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003eW/b\u0026thinsp;=\u0026thinsp;Water to Binder Ratio\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003eSlump\u0026thinsp;=\u0026thinsp;1.1 Inch\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003eMax Size of Aggregate\u0026thinsp;=\u0026thinsp;3/4\" water required for 1.1 slump would be 315 Ib/yd\u003csup\u003e3\u003c/sup\u003e\u003c/p\u003e \u003c/li\u003e \u003c/ul\u003e \u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab4\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 4\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eCalculations for mixed design\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"3\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCalculation Steps\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eDetails\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eValue\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eCement Content Calculation\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eWeight of Cement\u0026thinsp;=\u0026thinsp;Weight of Water / Water-Cement\u003c/p\u003e \u003cp\u003eRatio\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e630 lb/yd3\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eWeight of Water-binder\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e315 lb\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eWater-binder Ratio\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.5\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eCoarse Aggregate Estimation\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eFineness Modulus of Coarse Aggregate\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e3.07\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eVol. of Dry Robbed CA\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.5 or 0.6\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eDry Robbed \"U.W.\" of Coarse aggregate\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e145 lb/ft3\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eOven Dry Weight of Coarse Aggregate\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1957.5 lb/yd3\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eFine Aggregate Content\u003c/b\u003e\u003c/p\u003e \u003cp\u003e\u003cb\u003eEstimation\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eThe volume of Dry Fine Aggregate\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e27 ft3\u0026thinsp;\u0026minus;\u0026thinsp;21 ft3\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eThe volume of Fine Aggregate\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e6 ft\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eOven Dry Weight of Fine Aggregate\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e973.44 lb/yd3\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eTotal Batch Estimation per\u003c/b\u003e\u003c/p\u003e \u003cp\u003e\u003cb\u003eyd\u0026sup3;\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eWater-binder Volume\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e5.05 cft\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eCement Volume\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e3.256 cft\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eCoarse Aggregate Volume\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e11.0 cft\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eTotal Volume\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e21 cft\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eEstimated Batch per yd\u0026sup3;\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eWater-binder\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e315 lb\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eCement\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e630 lb\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eCoarse Aggregate\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1957.5 lb\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eFine Aggregate\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e973.44 lb\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eRatio Calculation\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eRatio of Cement\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eRatio of Fine Aggregate\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1.54\u0026thinsp;\u0026asymp;\u0026thinsp;1.5\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eRatio of Coarse Aggregate\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e3.1\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eFinal Ratio\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1:1.54:3.1\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e"},{"header":"6. Testing","content":"\u003cdiv id=\"Sec14\" class=\"Section2\"\u003e \u003ch2\u003e6.1 Sieve Analysis\u003c/h2\u003e \u003cp\u003eIn any quality determination of the particle size distribution, sieve analysis is the most important field test; it is defined it as the passing of aggregates through a logically devised series of sieves. For fine aggregates, the sieve sizes require No. 4, No. 8, No. 16, No. 30, No. 50, No. 100, and No. 200 as well as one collecting pan [\u003cspan citationid=\"CR64\" class=\"CitationRef\"\u003e64\u003c/span\u003e]. For coarse aggregates, the sieve sizes include No. 3, 2.5, 1.5, \u0026frac34;, \u0026frac12;, 3/8, and \u0026frac14;. Such an enormous study ensures the accurate selection of materials, which in turn helps in enhancing the quality of construction patterns significantly.\u003c/p\u003e \u003cp\u003eThe sieved aggregate is placed on top of the sieve and subjected to mechanical shaking. During this time, the particles undergo stratification according to size. After shaking the material, the next process is to weigh the remaining material on each sieve and calculate the cumulative weight distribution. The obtained information is useful in analyzing the grading of the aggregate, which is a fundamental fortification for the adequate performance of the concrete mixtures.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab5\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 5\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eGrading Assessment of Fine and Coarse Aggregates\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"5\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSieves #\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eWeight\u003c/p\u003e \u003cp\u003eRetained (gm)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003e% retained\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eCumulative% passing\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eCumulative% Retained\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e100\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e2.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e100\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e1.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e100\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e100\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e3/4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e269\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e26.9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e73.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e26.9\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e1/2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e582\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e58.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e14.9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e85.1\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e3/8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e121\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e12.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e2.8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e97.2\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e1/4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e11\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1.7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e98.3\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eTotal\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e307.5\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eFines Modulus (Fine\u003c/p\u003e \u003cp\u003eAggregate)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e= \u0026sum;Cumulative % Retained / 100 =\u003c/p\u003e \u003cp\u003e307.5 / 100\u0026thinsp;=\u0026thinsp;\u003cb\u003e3.07\u003c/b\u003e\u003c/p\u003e \u003cp\u003e\u003cb\u003eok\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eSieve Analysis (Coarse Aggregate)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eSieves #\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cb\u003eWeight\u003c/b\u003e\u003c/p\u003e \u003cp\u003e\u003cb\u003eRetained (gm)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cb\u003e% retained\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003cb\u003eCumulative% passing\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u003cb\u003eCumulative% Retained\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e100\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e3.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.64\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e99.36\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.64\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e16\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e8.7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1.74\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e97.62\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e2.38\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e25\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e14.18\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2.836\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e94.784\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e5.216\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e50\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e178.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e35.64\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e59.144\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e40.856\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e100\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e239\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e47.8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e11.344\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e88.656\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e200\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e37.12\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e7.424\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e3.92\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e96.08\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003epan\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e19.6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eTotal\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u003cb\u003e233.828\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eFines Modulus (Coarse\u003c/b\u003e\u003c/p\u003e \u003cp\u003e\u003cb\u003eAggregate)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e= \u0026sum;Cumulative % Retained / 100 =\u003c/p\u003e \u003cp\u003e233.83 / 100\u0026thinsp;=\u0026thinsp;\u003cb\u003e2.33\u003c/b\u003e\u003c/p\u003e \u003cp\u003e\u003cb\u003eok\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eFine aggregates must have a fineness modulus (FM) in the range of 2.3\u0026ndash;3.1 and coarse aggregates must also have an FM value within the stated limits in order to fulfill construction requirements. Interchange of any FM value outside the prescribed range is hereby termed unsuitable for any construction work for a coarse aggregate. Since our measured FM value falls within the accepted range, it confirms that the aggregates meet the standard requirements and are thereby suitable for preparing the geopolymer concrete mix for proper workability, compaction, and structural integrity.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec15\" class=\"Section2\"\u003e \u003ch2\u003e6.2 Workability\u003c/h2\u003e \u003cp\u003eWorkability was tested during this study using the slump test as described in ASTM C143, which delineates a \"Standard Test Method to Determine the Workability of Hydraulic Cement Concrete (by slump test)\u0026rdquo;[\u003cspan citationid=\"CR69\" class=\"CitationRef\"\u003e69\u003c/span\u003e]. In this test, a conic mold is filled with fresh concrete and removed so that the vertical settlement of the concrete can be observed. The result is a vertical measurement of slump, which is an indicator of workability for the mix. Generally, a higher slump is interpreted to indicate greater workability for easy placement and compaction, while a lower slump suggests a stiffer mix needing more effort to work with. The results of the slump tests were tabulated in Table\u0026nbsp;\u003cspan refid=\"Tab6\" class=\"InternalRef\"\u003e6\u003c/span\u003e; these results were further examined to ascertain that the mix of concrete complied with the specification of the project concerning the required flow and consolidation efficiency, extremely essential factors to secure structural stability and durability.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab6\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 6\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eSlump Values\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"4\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eS.No\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eRatio\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eidentifications\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eSlump in inch\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eConcrete with 0% Fly-Ash\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1.1\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e10%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eConcrete with 10% Fly-Ash\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.9\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e20%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eConcrete with 20% Fly-Ash\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e30%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eConcrete with 30% Fly-Ash\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec16\" class=\"Section2\"\u003e \u003ch2\u003e6.3 Compression Test\u003c/h2\u003e \u003cp\u003eThe compressive strength test was carried out to determine strength development within fly ash concrete and overall performance. Cylindrical specimens were prepared by keeping a concrete mix ratio of M20 (1:1.5:3) so that all batches remain uniform concerning material composition. It kept the uniform density in all the samples by vigorous tamping of the molds with a tamping rod. Following 24 hours of set time, the specimens were de-molded and immersed in a water tank for continued hydration at later ages.\u003c/p\u003e \u003cp\u003eThe number of complete specimens cast into cylinders was 12 for each curing period (7, 14, and 28 days) for a precise mean compressive strength result. The compressive strength test was conducted as per ASTM C39/C39M using a UTM[\u003cspan citationid=\"CR67\" class=\"CitationRef\"\u003e67\u003c/span\u003e]. Each specimen underwent the UTM individually, and a uniform compressive load was applied until failure. The compressive strength (\u0026#120590;\u0026#119888;) value was calculated using the expression:\u003cdiv id=\"Equa\" class=\"Equation\"\u003e\u003cdiv format=\"TEX\" class=\"mathdisplay\" id=\"FileID_Equa\" name=\"EquationSource\"\u003e\n$$\\:{\\sigma\\:}\\text{c}=\\frac{\\text{P}}{A}$$\u003c/div\u003e\u003c/div\u003e\u003c/p\u003e \u003cp\u003ewhere: P\u0026thinsp;=\u0026thinsp;Maximum load applied (N), A\u0026thinsp;=\u0026thinsp;Cross-sectional area of the specimen (mm\u0026sup2;).\u003c/p\u003e \u003cp\u003eFrom test results, it shows the use of fly ash enhances the long-term compressive strength due to pozzolanic action, which increases strength with time. The compressive strength of 10% fly ash replacement is noted to be 23.6 MPa, as contained in Table\u0026nbsp;\u003cspan refid=\"Tab7\" class=\"InternalRef\"\u003e7\u003c/span\u003e. The study results prove that fly ash makes concrete durable and performance-oriented, and henceforth, it seems to be a salt material for construction.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab7\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 7\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eCompressive strength results at 28 days\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"3\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eFly-Ash Replacement(%)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eCompressive Strength(MPa)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eCompressive Strength(Psi)\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e22\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e3190\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e10\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e23.6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e3442\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e20\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e21.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e3117.5\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e30\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e19\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2755\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec17\" class=\"Section2\"\u003e \u003ch2\u003e6.4 Tensile Strength Test\u003c/h2\u003e \u003cp\u003eThe tensile strength test has been done to determine how the fly ash concrete resists cracks and bond failure due to applied tension. These cylindrical specimens have been prepared using the concrete ratio of 1:1.5:3, and thus it has achieved batch uniformity in the material composition. To get the same consistency in density, concrete was compacted using a tamping rod. Specimens were de-molded after 24 hours of setting time and placed in a water tank for 28 days of continuous hydration. A total of 12 cylindrical specimens were cast to test parameterization for specific tensile strength. The splitting tensile test was carried out according to ASTM C496/C496M by a Universal Testing Machine (UTM)[\u003cspan citationid=\"CR70\" class=\"CitationRef\"\u003e70\u003c/span\u003e]. Loading them with the same load at the time of failure due to tensile. The tensile strength (\u0026#120590;\u0026#119905;) has been defined using the formula below:\u003cdiv id=\"Equb\" class=\"Equation\"\u003e\u003cdiv format=\"TEX\" class=\"mathdisplay\" id=\"FileID_Equb\" name=\"EquationSource\"\u003e\n$$\\:{\\sigma\\:}\\text{t}=\\frac{2P}{{\\pi\\:}\\text{d}\\text{L}}$$\u003c/div\u003e\u003c/div\u003e\u003c/p\u003e \u003cp\u003eWhere: P\u0026thinsp;=\u0026thinsp;Maximum applied load (N), d\u0026thinsp;=\u0026thinsp;Diameter of the specimen (mm), L\u0026thinsp;=\u0026thinsp;Length of the specimen (mm)\u003c/p\u003e \u003cp\u003eResults of the tests showed that the addition of fly ash improved internal cohesion, thereby making more tensile strength. The redesign of 10% replacement fly ash gains a tensile strength value of 4.2 MPa, which is 15% more than that of the control concrete sample. This was indicated to have an increase in strength when compared to 4.0 MPa. All these findings speak about using fly ash as a tool for the overall development of concrete, thus providing a way to adapt it structurally durably.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab8\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 8\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eTensile Strength results at 28 days\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"3\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eFly-Ash Replacement(%)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eTensile Strength(MPa)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eTensile Strength(Psi)\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e580\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e10\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e4.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e609\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e20\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e3.8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e551\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e30\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e3.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e507.5\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec18\" class=\"Section2\"\u003e \u003ch2\u003e6.5 Pull-out Test\u003c/h2\u003e \u003cp\u003eThe pull-out test procedure was selected to evaluate the bond between the reinforcement steel and the concrete matrix based on fly ash percentages of 0%, 10%, 20%, and 30%. The pull-out test was conducted using a hydraulically operated UTM capable of producing a pull-out force of 3000 psi concerning bond strength measurement. The sample arrangement was consolidated on a specially designed steel frame for testing, which simulated the bonding conditions in the field. The frame consisted of rigid steel with two plates, fastened with high-strength bolts. The upper plate was attached to the loading arm of the UTM, while the lower plate contained a hole to extract the embedded rebar during the actual pull-out test. The concrete specimens were thus placed in the test set-up in such a way as to guarantee uniform load application and accuracy in the measurement of bond performance during the test. Bond strength is determined as:\u003cdiv id=\"Equc\" class=\"Equation\"\u003e\u003cdiv format=\"TEX\" class=\"mathdisplay\" id=\"FileID_Equc\" name=\"EquationSource\"\u003e\n$$\\:{\\tau\\:}=\\frac{\\text{P}}{\\pi\\:dL}$$\u003c/div\u003e\u003c/div\u003e\u003c/p\u003e \u003cp\u003ewhere P\u0026thinsp;=\u0026thinsp;applied maximum load, d\u0026thinsp;=\u0026thinsp;diameter of the steel reinforcement bar, and L\u0026thinsp;=\u0026thinsp;length embedded in concrete.\u003c/p\u003e \u003cp\u003eThe results indicated that with the rise in fly ash content with a certain limit up to 10%, the bond strength exhibited a gradual increase. The control sample (0% fly ash replacement) had a bond strength value of 13.5 MPa, while 10% fly ash exhibited a marginally improved bond strength value (13.9 MPa). The 20% fly ash mix decreases in bond strength to 11 MPa. The lowest bond strength for 30% fly ash was reported at 9.7 MPa, and this was attributed to better microstructure densification leading to lower porosity and hence more adhesion.\u003c/p\u003e \u003cp\u003eThe improvement in bond strength has been attributed to the formation of CaSiH gel, which itself fills in and improves the bonding of the cement matrix and consequently enhances mechanical interlocking between concrete and steel. The reduction in micro-cracking provided further support for this stress transfer process, enabling bond behavior to be fostered. These findings suggest that fly ash in concrete will ensure structural performance in the long run while being an important alternative for minimizing environmental hazards contributed by cement-based materials. This study provides enough evidence to prove that fly ash improves bond strength (10%), and therefore it may be considered a way to increase the durability and performance of the reinforced concrete structures.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab9\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 9\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003ePull-out test results\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"3\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eFly-Ash Replacement(%)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003ePull-out Strength(MPa)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003ePull-out Strength(Psi)\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e13.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1957.5\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e10\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e13.9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2015.5\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e20\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e11\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1595\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e30\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e9.7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1406.5\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec19\" class=\"Section2\"\u003e \u003ch2\u003e6.6 Beam End Test\u003c/h2\u003e \u003cp\u003eBond strength testing between reinforcement steel and concrete matrix was carried out on bare beam ends on the concrete specimens with reinforcement embedded at one end. The preparation of the specimens was done at various percentages of fly ash replacement (0, 10, 20, and 30) to check how fly ash was affecting the bond performance. The test set-up consisted of a special loading frame. The use of a hydraulic universal testing machine (UTM) capable of applying a 3000 psi pulling force was employed for pullout failure. Thus, the application of load on the reinforced concrete samples was secured in the testing apparatus, making sure that it was well aligned and simulated the real bond conditions.\u003c/p\u003e \u003cp\u003eThe test apparatus consists of a rigid steel frame with two steel plates firmly bolted together with high-strength bolts. The upper steel plate is attached to the loading arm of the UTM, while the lower plate has a borehole to allow for rebar pullout during testing. The bond strength was determined from the expression:\u003cdiv id=\"Equd\" class=\"Equation\"\u003e\u003cdiv format=\"TEX\" class=\"mathdisplay\" id=\"FileID_Equd\" name=\"EquationSource\"\u003e\n$$\\:{\\tau\\:}=\\frac{\\text{P}}{\\pi\\:dL}$$\u003c/div\u003e\u003c/div\u003e\u003c/p\u003e \u003cp\u003ewhere P is the applied load, d is the diameter of the reinforcement bar, and L is the embedment length.\u003c/p\u003e \u003cp\u003eAs observed from the beam-end test outcome, bond strength was increased in progressive order with an increase in fly ash. The control concrete showed a bond strength of 12.0 MPa; with 10% fly ash, its bond strength became 13.5 MPa, which was only slightly higher. With 20% fly ash replacement, bond strength was observed to decrease to 11.76 MPa. The lowest bond strength recorded thus far was achieved by the mix with 30% fly ash replacement, which amounted to 9 MPa.\u003c/p\u003e \u003cp\u003eThe enhanced bonding performance due to pozzolanic activity with fly ash helps in refining the microstructure due to the formation of additional C-S-H gel, thus strengthening the interface between concrete and its reinforcement. A dense cementitious matrix reduces micro-cracking and improves stress transfer, promoting mechanical interlock. Thus, in addition to being beneficial to structure and environment, this paper shows a good solid case for increasing fly ash use as a sustainable alternative in concrete mixes since it increases bond strength. Table\u0026nbsp;\u003cspan refid=\"Tab10\" class=\"InternalRef\"\u003e10\u003c/span\u003e shows the results of the test.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab10\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 10\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eResults of beam end test\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"3\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eFly-Ash Replacement(%)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eBeam-End Test Strength(MPa)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eBeam-End Test Strength(Psi)\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e12\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1740\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e10\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e13.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1957.5\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e20\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e11.76\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1705.2\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e30\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1305\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003c/div\u003e"},{"header":"7. Results","content":"\u003cp\u003eAll cast samples of concrete mixtures were inspected using UTM to compare their structural characteristics. Furthermore, the specimens were examined by the guidelines established by the ASTM. The field study on concrete cylinders was carried out in the concrete laboratory of SUIT\u0026apos;s Civil Engineering department in Peshawar. The following findings were obtained.\u003c/p\u003e\n\u003cdiv id=\"Sec21\" class=\"Section2\"\u003e\n \u003ch2\u003e7.1 Sieve Analysis\u003c/h2\u003e\n \u003cp\u003eSieve analysis of the fine and coarse aggregates serves their qualification against the engineering specifications for construction purposes. The sieve analysis was conducted to quantify the particle size distribution and gave consequent data as shown in Table \u003cspan class=\"InternalRef\"\u003e5\u003c/span\u003e. The Fineness Modulus (FM), computed for the fine aggregate, was 3.07, which is within the accepted range of 2.3\u0026ndash;3.1. This indicates a moderately well-graded profile conducive to workability and reduced interstitial voids, assuring maximum mechanical performance of concrete matrices. Well-graded fine aggregates will promote good particle packing and increase the densification, compressive strength, and durability of the composite material. The coarse aggregates have shown an FM of 2.33, which is slightly below the recommended one. Such gradation is inefficient and would, therefore, result in poor compaction, increased voids, and mismatching of structural homogeneity, which could bring down the load-bearing capacity and long-term durability of the concrete in a mature state. Since these shortcomings were noted, corrective measures were taken in the mixing with additional fractions of aggregate or in optimizing the gradation curves through the selective blending of aggregates to ensure a more uniform particle size distribution.\u003c/p\u003e\n \u003cp\u003eThe grain size distribution curves in Fig.\u0026nbsp;5b display the passed particle percentage of standardized sieves versus logarithmic particle measurement in both fine and coarse aggregates. The steep slope of the fine aggregate curve (sand) indicates high quantities of material smaller than 0.6 mm and between 0.6 mm and 1.18 mm while remaining coarse aggregates exceed 1.18 mm. The course aggregate curve (gravel) exhibits a progressive increase in the larger size range (\u0026gt;\u0026thinsp;4.75 mm) where it retains 10% of the material at the 9.5 mm sieve and releases 90% at the 19 mm sieve thus demonstrating a balanced big particle mixture. The intersection of these curves at the 4.75 mm sieve demarcates the boundary between fine and coarse fractions. The fineness modulus of fine aggregate and the nominal maximum size of coarse aggregate can be determined from this figure to verify adherence to standards like ASTM C33. A proper grading of fine aggregates should produce a smooth continuous curve while proper grading of coarse aggregates should achieve balanced distribution to minimize voids and optimize packing efficiency which leads to improved concrete properties and durability. The illustration demonstrates why correct grading remains essential to decrease cement requirements alongside segregating prevention and creating economical concrete mixes with superior performance.\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec22\" class=\"Section2\"\u003e\n \u003ch2\u003e7.2 Workability Test\u003c/h2\u003e\n \u003cp\u003eUnder standard workability parameters, the concrete mixture underwent an experimental discount of the ASTM C143 slump test, designed to evaluate the consistency and placement characteristics of hydraulic cement concrete. This procedure involves placing fresh concrete in a conical mold (height: 300 mm, bottom diameter: 200 mm, top diameter: 100 mm), which is then rodded in three layers to expel any trapped air. Following a standard procedure to strip the mold, controlled subsidence of the concrete takes place; the accompanying vertical displacement is another important parameter describing the material\u0026apos;s rheological behavior. Higher slump values indicate better fluidity and ease of placement/consolidation, while lesser slump describes a stiff matrix that requires extra energy for handling and finishing. Developmentally described in Table \u003cspan class=\"InternalRef\"\u003e6\u003c/span\u003e, the experimental study aimed to quantify workability in respect to gradual fly-ash substitution (varying 0\u0026ndash;30% fly ash by mass of cement) influence and showed that the control mix with 0% fly ash had recorded a minimum slump of 1.1 inches (2.79 cm), which is an indication of moderate workability suitable for conventional placement. Gradual replacement of fly ash exhibited an enormous slump loss: 10% fly ash replacement reduced this to almost 0.9 inches (2.29 cm) with the 20% and 30% fly ash mixes with zero slump into a non-flowable and cohesion-dominated state. This is attributed to combined synergistic effects from fly ash\u0026apos;s high specific surface area and pozzolanic reactivity, thus increasing the demand for interstitial water, hence resulting in less free water available for flow behavior particle lubrication. Fly ash and slump share an inverse correlation as corroborated by empirical observations and confirmed in Fig. 6b. Figure 6a underlines the procedural legitimacy of slump test compliance to specification. These results are meaningful for mix optimizations from the aspect of placement, placing designs of stringent workability while maintaining mechanical performance. With this in mind, adjusting the water-cement ratio could counter the stiffening action of the fly ash, producing a mix containing a high-range water-reducing admixture, such as poly-carboxy late-based superplasticizers, or tuning the aggregate grading for enhanced particle pack density. All these enhancements represent avenues for achieving concrete\u0026apos;s rheological behavior objectives in practice while maintaining the durability and structural integrity of the hardened concrete matrix.\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec23\" class=\"Section2\"\u003e\n \u003ch2\u003e7.3 Compression Test\u003c/h2\u003e\n \u003cp\u003eThe compressive strength test of fly ash concrete was performed to assess the effect of fly ash on the mechanical performance. 150 mm diameter \u0026times; 300 mm high cylindrical specimens were cast for uniformity in batch preparation, using premixed M20-grade (1:1.5:3 cement: sand: coarse aggregate) mix. The compaction was thorough with the specimens de-moulded after 24 hours and cured in a temperature-controlled water tank (23\u0026thinsp;\u0026plusmn;\u0026thinsp;2\u0026deg;C) until the testing at 7, 14, and 28 days of casting. The tests were conducted according to ASTM C39/C39M using UTM, where compressive strength (𝜎𝑐) has been obtained from the formula: Peak failure load (𝑃) divided by cross-section area (𝐴) of the specimen.\u003c/p\u003e\n \u003cp\u003eThe 28-day compressive strength results (Table \u003cspan class=\"InternalRef\"\u003e7\u003c/span\u003e, Fig. \u003cspan class=\"InternalRef\"\u003e7\u003c/span\u003eb) did indicate an apparent non-linear relationship between fly ash content and strength. As for other M20-grade concrete, the control mix (0% fly ash) measured 22 MPa (3,190 psi). On replacing the control mix with 10% fly ash, the strength improved to 23.6 MPa (3,442 psi), which is a 7.3% improvement attributed to the pozzolanic reaction leading to the secondary formation of C-S-H, thereby densifying the matrix. But higher replacement percentages did not translate into higher performance, as with 20% fly ash the strength had dropped to 21.5 MPa (3,117.5 psi); while further decreasing to 19 MPa (2,755 psi) for 30% replacement. Such behavior indicates poor particle packing at these high replacement percentages, where excessive amounts of fly ash act largely as inert fillers, diluting the cement binder.\u003c/p\u003e\n \u003cp\u003eThe best performance was noted for 10% of the replacement, which is an indication of the suggestion that fly ash promotes latent long-term durability in terms of time for pozzolanic reactions, with larger proportions establishing the importance of informed cement-pozzolan ratios to avoid weakening the matrix. For this reason, the findings favor 10% fly ash as an environmentally friendly strength enhancement additive and cement-reducing material beyond which caution is advised; however, further optimization is warranted concerning structural applications.\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec24\" class=\"Section2\"\u003e\n \u003ch2\u003e7.4 Tensile Strength\u003c/h2\u003e\n \u003cp\u003eThe splitting tensile test (ASTM C496/C496M) evaluated fly ash concrete\u0026apos;s tensile strength in resisting crack and bond failure under tension. Cylindrical specimens were made from a batch employing a cement-sand-coarse aggregate mix ratio of 1:1.5:3 to ensure compositional consistency across batches. Specimens were tamped for uniform density, de-molded after 24 hours, and cured in a temperature-controlled water tank (23\u0026thinsp;\u0026plusmn;\u0026thinsp;2\u0026deg;C) for 28 days for complete hydration. A total of twelve specimens were tested using a Universal Testing Machine (UTM), while tensile strength (\u0026sigma;t) was calculated from the applied load, diameter, and length of the specimen using the expression \u0026sigma;t\u0026thinsp;=\u0026thinsp;2P/(\u0026pi;dL).\u003c/p\u003e\n \u003cp\u003eThe results (Table \u003cspan class=\"InternalRef\"\u003e8\u003c/span\u003e, Fig.\u0026nbsp;8b) indicate that there exists a nonlinear relation between the fly ash content and the tensile strength. The plain mixture (0% fly ash) had a tensile strength in approximate terms of 4.0 MPa (580 psi), and this has been agreed upon for the M20 grade concrete. With the addition of 10% fly ash replacement, the strength improved to a maximum of 4.2 MPa (609 psi), representing a 15% improvement due to increasing internal cohesion afforded by the pozzolanic activity of fly ash, refinement of the interfacial transition zone (ITZ), and enhanced secondary calcium silicate hydrate (C-S-H) formation. But higher percentage replacement led to lower performance, i.e., bond strength at 20% replacement came down to 3.8 MPa (551 psi), while at 30% replacement, the value dropped to 3.5 MPa (507.5 psi). This was attributed to excess fly ash, acting as an inert filler, hampering the consolidation of particles to yield less effective binders, resulting in lower strength of the matrix.\u003c/p\u003e\n \u003cp\u003eResults showed that fly ash serves dual purposes: to improve tensile resistance due to microstructural densification at 10% replacement that is then outdone at higher replacement levels due to lack of a full pozzolanic reaction and increased water demand. A specimen under test is shown in Fig. 8a, which has its maximum tensile strength at 10% fly ash treated graphically in Fig. \u003cspan class=\"InternalRef\"\u003e7\u003c/span\u003eb. These findings drew attention to the need for optimizing the fly ash content concerning two objectives, sustainability and structural performance, as one way to achieve durability may be to replace 10% of cement with fly ash.\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec25\" class=\"Section2\"\u003e\n \u003ch2\u003e7.5 Pull-out Test\u003c/h2\u003e\n \u003cp\u003eIn using the pull-out test, the interfacial bond strength between steel reinforcement and fly ash-modified concrete was intra-corporeally assessed for evaluating adhesion under axial tension. Specimen preparation adopted fly ash replacement levels of 0%, 10%, 20%, and 30% corresponding to the test on the hydraulically actuated Universal Testing Machine (UTM). It also built a steel structure that distributed the same load in a test simulation of real-life bonding conditions. The bond strength (𝜏) is calculated by the ratio of the maximum pull-out load (𝑃) to the product of the rebar circumference (\u0026pi;𝑑) and the embedding length (𝐿).\u003c/p\u003e\n \u003cp\u003eThe results revealed a non-linear relation between the content of fly ash and bond performance. The control mix (0% fly ash) yielded a reference bond strength of 13.5 MPa (1,957.5 psi). As expected, it was close to conventional reinforced concrete. In replacing 10% fly ash, bond strength improved slightly, recording 13.9 MPa (2,015.5 psi). It was, therefore, observed that because of pozzolanic activity, fly ash improved interfacial adhesion. This indicated that by secondary C-S-H gel formation, which densified the concrete matrix, porosity was reduced, and the mechanical interlock contributed to the steel-concrete interface\u0026apos;s component. Greater fly ash replacements were associated with progressive solvent losses in bond strength (20% replacement reduced bond strength to 11.0 MPa (1,595 psi)); a 30% replacement yields the lowest value of 9.7 MPa (1,406.5 psi)).\u003c/p\u003e\n \u003cp\u003eHowever, the low value as noted affirms the effect of strengthening at 10% substitution of fly ash on the improvement of the interfacial transition zone (ITZ) due to microstructural densification that lessens micro-cracking incidence and enhances stress transfer. Hence, in more than 10% substitution, the unreacted fly ash particles, acting as inert filler, dilute the cementitious binder and diminish the cohesive forces at the interface. Results include lower adhesion and higher interfacial slippage during load.\u003c/p\u003e\n \u003cp\u003eAs shown in Fig. 9b, the relationship of bond strength is parabolic, and this underlines the critical balance between the pozzolanic benefit and filler limitation of fly ash. These findings argue for a 10% fly ash substitution for optimal bond performance in reinforced concrete thus providing a sustainable measure toward reduced cement consumption while at the same time providing structural integrity. Greater replacement levels necessitate other economics like hybrid pozzolan blends or superplasticizers to cater to losses in adhesion while still ensuring compliance with engineering requirements. Thus, what the study does is to emphasize the need for calibrated application of fly ash to ensure durability and high performance in reinforced concrete systems.\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec26\" class=\"Section2\"\u003e\n \u003ch2\u003e7.6 Beam End Test\u003c/h2\u003e\n \u003cp\u003eThe bond strength between fly ash-modified concrete and reinforcement steel has been further studied using a beam-end test to simulate interfacial adhesion under actual service conditions. Specimens were prepared with different levels of fly ash replacement\u0026mdash;0%, 10%, 20%, and 30%\u0026mdash;with steel embedded at one end. The experiment was done using a hydraulic Universal Testing Machine (UTM) made to apply pull force to samples amounting to 3,000 psi and embedded into a rigid steel frame to hold them in alignment with physically accurate pressure dynamics. The following equation was used to calculate bond strength (𝜏): 𝑃/(\u0026pi;𝑑𝐿).\u003c/p\u003e\n \u003cp\u003eResults showed a nonlinear relationship between fly ash and bonding performance. The control mix, which was without fly ash (0%), recorded a bond strength of 12.0 MPa (1,740 psi), which would conventionally serve as the benchmark for concrete. Bond strength increased to 13.5 MPa (1,957.5 psi) when 10% fly ash was substituted, indicating a 12.5% improvement due to the pozzolanic activity of fly ash; which, in turn, enhanced the secondary formation of the calcium silicate hydrate (C-S-H) gel that densifies interfacial transition zones (ITZs), reduces porosity, and augments mechanical interlocking of steel with the concrete matrix. On the other hand, the continued increase in the percentages did not improve the values. attained 20% fly ash replacement reduced bond strength to 11.76 MPa (1705.2 psi), while using 30% replacement yielded the lowest value of 9.0 MPa (1,305 psi).\u003c/p\u003e\n \u003cp\u003eThe lower substitution of 10% indicates that fly ash can improve the ITZ by dense microstructures, thereby eliminating micro-cracking and increasing the efficiency of stress transfer at this point. However, any increases to the substitution above 10% would add unreacted fly ash particles acting as an inert filler in the cementitious binder, leading to the dilution of cohesive forces at the steel-concrete interface, hence causing weaker adhesion and an increased interfacial slippage when loaded. The evidence is shown in the sharply declining value at 20\u0026ndash;30% replacement.\u003c/p\u003e\n \u003cp\u003eAs shown in Fig. 9b, the parabolic trend captures the kind of critical tipping point when the pozzolanic good qualities of fly ash turn to limitation as part of cement. These findings would reconfirm that replacing 10% of fly ash would be the most strategic maximum efficiency point where bond performance in reinforced concrete can be improved, offering advantages from the sustainability viewpoint because it reduces the consumption of cement. Greater substitutions would require countermeasures such as optimal gradation or the use of superplasticizers to maintain structural reliability. The work highlights the necessity for carefully calibrated use of fly ash in designing durable, high-performance concrete systems while calling for its use in green construction practices.\u003c/p\u003e\n\u003c/div\u003e"},{"header":"8. Conclusion","content":"\u003cp\u003eIn this research, an attempt has been made to conduct a systematic study of steel reinforcement in concrete bonding influenced by Type-F fly ash with testing as part of a larger experimental program. The most important parameters evaluated in this work to look for an optimum level of fly ash substitution will be compressive strength, tensile strength, and bond strength.\u003c/p\u003e \u003cp\u003e \u003cul\u003e \u003cli\u003e \u003cp\u003e\u0026middot;A 10% replacement level of fly ash as partial cement replacement shows the most promising results, wherein the compressive strength of concrete is 23.6 MPa, tensile strength is 4.2 MPa and bond strength is 13.9 MPa. Further refinements occurred due to the ongoing process of pozzolanic reaction, and refinement incorporated with microstructure improved interfacial adhesion.\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003eWith the increase of percentage replacement (20\u0026ndash;30%), a gradual decrement in the set of developed mechanical properties was observed; however, the mixture with 30% replacement revealed a slump value of 0. This adverse phenomenon can be attributed to an undue increase in fly ash not affecting cement hydration and an increase in loss of cohesion between the particles.\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003eMore associated with the increased bond strength attainable with a 10% blend of fly ash is the formation of a secondary C-S-H gel, which made the cementitious matrix denser and reduced the porosity at interfaces.\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003eAggressive replacement with fly ash generated negative effects on mechanical performance and workability, paralleled with the otherwise optimal level of replacement to ensure faster development of strength while providing satisfactory durability.\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003eSuch experimental findings illuminate the active role of fly ash as both pozzolanic material and microstructural densifier in support of its application in high-performance concrete.\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003eSustainable use of fly ash as a cement substitute achieves a reduction in cement consumption, which translates to a reduction in CO₂ emissions and improves the beneficial reuse of industrial by-products.\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003eThe replacement, with 10% fly ash substitution, is an effective method of producing durable high-performance concrete in line with sustainable construction and circular economy objectives across the globe.\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003eThis research sets a primacy for future investigations as to how the enhancement of properties of fly ash interventions can be evaluated concerning bond properties in conventional and geopolymer concrete systems.\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003eThe experimental results have been obtained using Type-F fly ash and locally available aggregates, so other combinations of materials will give different results from region to region.\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003eThe tests were carried out in a laboratory, and its long-term permanence of fly ash-modified concrete under real-exposed environments requires evaluation for ingress of chlorides and freeze-thaw cycles.\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003eReplacement levels are from 0\u0026ndash;30% fly ash, without the incorporation of a hybrid binder system that contributed to supplementary cementitious materials, like silica fume or ground granulated blast-furnace slag.\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003eFuture studies would involve the synergistic uses of fly ash and other pozzolanic materials to ensure no deterioration of performance arising from prolonged exposure of fly ash cementitious composites too harsh.\u003c/p\u003e \u003c/li\u003e \u003c/ul\u003e \u003c/p\u003e"},{"header":"9. Recommendation","content":"\u003cp\u003eThe following recommendations stem from experimental results to improve fly ash-modified concrete practical applications as well as future research projects.\u003c/p\u003e \u003cp\u003e \u003cul\u003e \u003cli\u003e \u003cp\u003eThe overall recommended optimal dosage, at which about 10% of OPC is replaced with fly ash, enhances bond strength, compressive strength, and tensile strength while keeping workability within acceptable limits.\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003eHigher levels of replacements (\u0026ge;\u0026thinsp;20%) may also lead to compromise in the mechanical properties and, therefore, need to be carefully optimized through advanced mix design procedures.\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003eThe loss of workability with increasing fly ash content hence warrants the use of high-range water-reducing admixtures or superplasticizers to attain the desired flow properties.\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003eConsideration should be given to adjusting the water-binder ratio and optimizing overlay gradation to minimize the stiffening effect of fly ash.\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003eFurther, the mechanical and durability performance of 10% fly ash-modified concrete establishes its suitability for reinforced concrete structures, particularly for green infrastructure and high-performance applications.\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003eFurther studies should evaluate its long-term durability under field conditions, including chloride ingress resistance, sulfate attack, freeze-thaw cycles, and carbonation.\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003eFor promoting mechanical performance and durability, the interaction of fly ash with other SCMs such as silica fume, GGBFS, and meta-kaolin should be considered in the future.\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003eThe hybrid binder systems may also counteract the strength diminution observed at high fly ash replacement, hence enhancing the sustainability benefits.\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003eIn view of the possibility of carbon reduction and waste reutilization, the inclusion of fly ash should be promoted in infrastructural mega-projects and sustainable building activities.\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003eThe policy frameworks should promote the use of fly ash-based concrete as a green alternative to conventional cementitious materials.\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003eFuture studies need to test the structural behavior of fly ash-modified concrete on dynamic loading operations such as seismic resistance and fire performance.\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003eLong-term field studies are planned to measure durability, microstructural evolution, and service life performance in different environmental situations.\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003eFuture evaluation of the effect of various curing conditions and those of accelerated aging of the mechanical and bond properties of fly ash-modified concrete is mandated.\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003eThis essentially can be a guideline to optimize fly ash-based concrete for the sustainable and high-performance construction domain.\u003c/p\u003e \u003c/li\u003e \u003c/ul\u003e \u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e \u003ch2\u003eConflicts of Interest\u003c/h2\u003e \u003cp\u003eThe authors of this article state that there are no conflicts of interest in this work.\u003c/p\u003e \u003c/p\u003e\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\u003cp\u003eInvestigations were conducted by Adnan and Ahmad Jawad, the methodology was developed by both Adnan. Writing, review, editing, and supervision were overseen by Adnan, and the Introduction and software were done by Adnan, Ahmad Jawad. The completed paper has been seen and approved by all authors.\u003c/p\u003e\u003ch2\u003eAcknowledgement\u003c/h2\u003e\u003cp\u003eThe authors wish to express thanks to the Department of Civil Engineering (SUIT) from the bottom of their hearts, for their substantial support and assistance during the experimental effort.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eMonteiro PJ, Miller SA, Horvath A (2017) Towards sustainable concrete. 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Australian J Struct Eng 24(3):254\u0026ndash;263. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttp://dx.doi.org/10.1080/13287982.2023.2167644\u003c/span\u003e\u003cspan address=\"10.1080/13287982.2023.2167644\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eStandard A (2015) \u003cem\u003eC618-15 standard specification for coal fly ash and raw or calcined natural pozzolan for use in concrete.\u003c/em\u003e ASTM International: West Conshohocken, PA, USA. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1520/C0618-22\u003c/span\u003e\u003cspan address=\"10.1520/C0618-22\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eAstm C (2015) Standard test method for relative density (specific gravity) and absorption of fine aggregate. ASTM Curr Ed Approved Jan 1. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1520/C0128-07A\u003c/span\u003e\u003cspan address=\"10.1520/C0128-07A\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eAstm C (2006) Standard test method for sieve analysis of fine and coarse aggregates. ASTM C 136\u0026ndash;106. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1520/C0136-06\u003c/span\u003e\u003cspan address=\"10.1520/C0136-06\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eASTM C (2007) 192/C 192M Standard Practice for Making and Curing Concrete Test Specimens in the Laboratory. Annual Book ASTM Stand 4. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1520/C0192_C0192M-02\u003c/span\u003e\u003cspan address=\"10.1520/C0192_C0192M-02\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eInternational A (2022) Standard specification for mixing water used in the production of hydraulic cement concrete. ASTM Intenational DOI. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1520/C0511-21\u003c/span\u003e\u003cspan address=\"10.1520/C0511-21\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eStandard A (2020) C39/C39M (2015) Standard Test Method for Compressive Strength of Cylindrical Concrete Specimens, vol 9. Annual Book of ASTM Standards. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1520/C0039_C0039M-18\u003c/span\u003e\u003cspan address=\"10.1520/C0039_C0039M-18\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eACI A (2019) 318\u0026thinsp;\u0026ndash;\u0026thinsp;19 \u0026amp; ACI 318R-19: Building code requirements for structural concrete and commentary. American Concrete Institute, Farmington Hills, MI, USA. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://www.concrete.org/newsandevents/news/newsdetail.aspx?f=51719135\u003c/span\u003e\u003cspan address=\"https://www.concrete.org/newsandevents/news/newsdetail.aspx?f=51719135\" targettype=\"URL\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eInternational A (2020) \u003cem\u003eASTM C143/C143M-20, Standard Test Method for Slump of Hydraulic-Cement Concrete\u003c/em\u003e. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1520/C0143_C0143M-12\u003c/span\u003e\u003cspan address=\"10.1520/C0143_C0143M-12\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eASTM A (2017) C496/C496M-17 Standard test method for splitting tensile strength of cylindrical concrete specimens. Am Soc Test Mater. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1520/C0496_C0496M-17\u003c/span\u003e\u003cspan address=\"10.1520/C0496_C0496M-17\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"Fly-ash, Reinforcing Steel, Concrete bond properties, Bond strength, Sustainable construction, Ordinary Portland Cement, Eco-friendly concrete","lastPublishedDoi":"10.21203/rs.3.rs-6337687/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-6337687/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eA significant contributor to CO₂ emissions is cement production, thus raising interest in fly ash being accepted as a sustainable alternative. The study attempts to quantify the variations in bond strength for 0\u0026ndash;30% fly ash replacement, interrelate the properties of fly ash to the microstructure of the interface transition zone (ITZ), and establish the optimum replacement ratios for structural applications. The experiments were carried out on the Grade 53 OPC concrete (20 MPa target strength, 0.5 water-binder ratio) using measurements for compressive (ASTM C39), tensile (ASTM C496), and bond strengths (ASTM C900). The results found the 10% fly ash replacement optimal, enhancing compressive strength by 7.3% (23.6 MPa), tensile strength by 5% (4.2 MPa), and bond strength by 3% (13.9 MPa), attributed to pozzolanic densification of the ITZ. With greater fly ash substitutions (20\u0026ndash;30%), compressive strength dropped 14\u0026ndash;25% (to 19 MPa) and bond strength by 28\u0026ndash;39% (to 9.7\u0026ndash;11 MPa) due to unreacted fly ash diluting the binder along with very poor workability loss (slump: 0\u0026ndash;0.9 in.). The study shows that fly ash acted as an ITZ microstructural enhancer at \u0026le;\u0026thinsp;10% and a performance-deteriorating agent beyond. The findings propose a 10% level of fly ash as the sustainable limit, representing an optimal balance between structural integrity and environmental efficiency. Super-plasticizers with silica fume/slag are recommended to address the workability issues associated with larger substitutions. Future work must tackle durability against exposure to chloride, carbonation, and seismic loads. This study thus far has furthered eco-considered construction by allowing fly ash use to meet engineering demands.\u003c/p\u003e","manuscriptTitle":"A Comprehensive Analysis of the Influence of Fly Ash on the Bond Properties between Reinforcing Steel and Concrete","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-04-22 08:38:06","doi":"10.21203/rs.3.rs-6337687/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"f7755262-955b-458e-9e02-5cbf435babcb","owner":[],"postedDate":"April 22nd, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2025-07-28T15:56:40+00:00","versionOfRecord":[],"versionCreatedAt":"2025-04-22 08:38:06","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-6337687","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-6337687","identity":"rs-6337687","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}