Investigation of Crab (Portunus pelagicus) Shells in Concrete as a Potential Substitute for Fine Aggregate

Investigation of Crab (Portunus pelagicus) Shells in Concrete as a Potential Substitute for Fine Aggregate | 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 Method Article Investigation of Crab (Portunus pelagicus) Shells in Concrete as a Potential Substitute for Fine Aggregate Josef Hadipramana, Fetra Venny Riza, Shahrul Niza Mokhatar This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-3904460/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 Blue crab shell (Portunus pelagicus) is a fairly abundant domestic waste in the Indo-Pacific and has the potential to be reused. This study aimed to take advantage of the benefit of crab shells, which contain a lot of calcium carbonate and can potentially help the cement hydration reaction to create concrete strength. This study analyzed the mechanical properties of concrete containing crab shell powder (CSP). The composition of crab shell powder as a substitute for fine aggregate (FA) with variations of 5%, 7%, and 8% wt. FA. Crab shells (CS) are dried and finely crushed with a diameter of 1/8 inch, or equivalent to the diameter of FA. This study uses w/c ratios of 0.4 and 0.5 and all aggregates in SSD condition. The results show that the compressive strength of concrete containing CSP is above the strength of the design concrete. The composition of 5% CSP at a w/c ratio of 0.4 is equivalent to the strength of normal concrete with a w/c of 0.5%. The result showed the potential for CSP to replace fine aggregate while helping the cement hydration process. crab shell calcium-carbonate hydration cement Figures Figure 1 Figure 2 Figure 3 Figure 4 1. Introduction Many studies use a variety of elements to supplement or replace concrete ingredients to achieve the best concrete strength performance. Using abandoned materials or debris that is cementitious and disrupts the environment is one alternative for increasing the strength of concrete to be more inexpensive and environmentally beneficial. Crab skin (Lat: Portunus Pelagicus) was chosen for this study because it contains Calcium Carbonate (CaCO3) in amounts ranging from 40–70%, depending on the species variety. (Raya et al., 2015 ). Crabs are extensively dispersed throughout Indo-Pacific waters, collected in open waters, or grown in aquaculture. (Azra & Ikhwanuddin, 2015 ). Indonesian crab export commodities yearly amounted to 604,215–625,000 tons/year without the shell form. The figure can be calculated if the crab shells weigh up to 25% − 50% of the total weight of the crab (Raya et al., 2015 ), then the potential waste of crab shells of 302,108–312,50 tons can be generated per year. The addition of Calcium Carbonate (CC) in mortar can increase the workability, mechanical properties, and durability of the concrete (Sua-Iam & Makul, 2013 ) (Lertwattanaruk et al., 2018 ). Using CC in mortar reduces the unit weight of concrete due to the specific gravity of CC being lower than cement (Promsawat et al., 2020 ). If, in this study, CC partially replaced sand, then the volume of powdered material would increase due to the bulk density of CC being lesser than fine aggregate. The result is reduced segregation due to compaction. The shape and texture of CC and sand are very different, so mortar containing CC makes it easier to fill pores in concrete; hence, CC reduces intergranular friction (Matos et al., 2019 ). The potential of CC to accelerate the setting and hardening of concrete performs very high by providing nucleation sites, increasing the contact points between materials and increasing the performance of the effective water-to-cement ratio (Camiletti et al., 2013 ). Mechanical properties include compressive strength, split tensile strength, modulus of elasticity (MoE), and modulus of rupture (MoR), which are parameters needed in every concrete. Concrete in a loaded state under actual conditions bears pressure, tension, and torque variables. Therefore, the basic parameters affecting these variables must be met. The flexural strength of concrete acts against horizontal and vertical loads on concrete resists inertia loads, and resists moments that act at a certain point on concrete beams. Therefore, this study investigates the mechanical properties of concrete containing CSP as a potential new material that does not yet exist. 2. Materials and Methods 2.1. Materials The Indonesian Standard and ASTM (ASTM C 127-01, 2001 )(AASHTO T 19M/T 19 − 14, 2015)(ASTM-C-128, 2003 ) were used to determine the feasibility test of fine (FA) and coarse (CA) aggregates in this study. The results of the material feasibility test are presented in Table 1 . The sieve analysis test obtained the Fineness Modulus (FM) (SNI-ASTM-C-136, 2012 ). Several other tests are also performed, including density, bulk density, specific gravity, and absorption FA and CA. (ASTM C 127-01, 2001 )(ASTM-C-128, 2003 ). This material test must be carried out because the material is a natural aggregate mined from downstream rivers, where there is a lot of dirt and mud. Crab skin powder is obtained using several processing processes. First, the skin is cleaned with water from organic residues and then dried in an oven at 80º-90ºC for 12 hours. Heating is done by trial and error until it is obtained that the crab skin is free from organic residues. Next, the crab shells are crushed by pounding manually (crushing can be done using a machine) until the largest diameter passes through a 3/8-inch sieve. This is the largest diameter of sand, but the powder is finer than sand. Table 1 Properties of the constituent materials of concrete Properties Coarse Aggregate Limitation Fine Aggregate Limitation Cement Fineness Modulus (FM) (%) 7.20 6–7 2.49 1.5–3.8 - Density (gr/cm 3 ) 2.723 - 2.53 - 1.439 Specific gravity (gr/cm 3 ) - - - - 3.102 Bulk Density (gr/cm 3 ) 1.31 Min. 1.125 1.15 Max. 1.125 - Water content (%) 0.67 0.5–1.5 2.25 2.1–2.3 - Absorption (%) 0.777 Max. 4 1.83 Max. 2 - Mud Content (%) 0.67 Max. 1 3.67 Max. 5 - Maximum diameter (mm) 40 - 2.36 - - Abrasion (%) 16.460 - - - - 2.2 Mix Design and Experimental Method The concrete planning design uses the Indonesian National Standard (SNI 03-2834, 2000 ). The proportions of each concrete are presented in Table 2 , where 2 series were made with different w/c ratios of 0.4 and 0.5. Each series has 4 variations in crab shell powder content of 5%, 7%, and 8% wt. of FA. One sample was made without crab shell powder (CSP) to compare and control for other variations. This investigation mix design uses 20 MPa design concrete. Mixing the mortar is like making normal concrete, namely first mixing the FA, cement, and crab shells powder so that it is mixed evenly for about 3 minutes. The CA is added and rotated for 1.5 minutes, and finally, the water is then rotated for 2 minutes until evenly mixed. The slump test is carried out to determine the workability of fresh concrete. Concrete samples are made in a cylindrical shape with a cross-sectional area of ​​Ø 150mm and a height of 300mm for compressive strength test, splitting tensile test, and modulus of elasticity. Meanwhile, the Modulus of Rupture is a prism with a cross-section of 150mm x 150mm and a length of 600mm. All samples were made in 5 pieces for each test. Table 2 Mix Proportion of Concrete containing CSP. Sample Designation Percentage of Crab Shell Ratio of w/c Cement Fine Aggregate (FA) Coarse Aggregate (CA) Water (% wt. of FA) (Kg/m 3 ) (Kg/m 3 ) (Kg/m 3 ) (Kg/m 3 ) SR-1 5 0.4 417.5 408.7 1444.4 167 SR-2 7 0.4 417.5 408.7 1444.4 167 SR-3 8 0.4 417.5 408.7 1444.4 167 BN-1 - 0.4 417.5 408.7 1444.4 167 TR-1 5 0.5 334.0 466.4 1472.0 167 TR-2 7 0.5 334.0 466.4 1472.0 167 TR-3 8 0.5 334.0 466.4 1472.0 167 BN-2 - 0.5 334.0 466.4 1472.0 167 3. Results and Discussion 3.1 Sieve Analysis The dominant strength of concrete is formed from the aggregate that forms it, where the size of the aggregate can fill the spaces in the concrete mold. The aggregate gradation is important in concrete strength (Rashid et al., 2009 ). Figures 1 and 2 show the FA and CA gradations, respectively. Both aggregate particle size distributions are within the required (sufficient) range for each coarse and fine aggregate in accordance with the limits determined by ASTM C-33(ASTM C-33-03, 2001 ). Figures 1 shows that FA is in the rather coarse category, and Fig. 2 shows that the coarse aggregate is close to rather fine. This condition provides an advantage when the aggregate can fill the voids available in the concrete. 3.2 Workability The workability test on concrete containing CSP was carried out in the fresh state phase, with the results shown in Table 3 . The slump values ​​for both ratios are 30 to 45 mm, including in low slump. The w/c ratio of 0.4 has a greater value than the w/c ratio of 0.5. The ratios of w/c 0.4 and 0.5 have the highest slump values ​​of 45 mm and 42, respectively, at 8% CSP composition. The presence of CSP contributes to lowering the surface tension of the mortar, thereby increasing the slump value. Lime has a high water affinity because lime has a high interfacial surface area and lower superficial tension force (Pavía et al., 2014 ). The consistency of the mixture and the cohesion of the materials in the mixture greatly influence workability. Workability affects strength because of the mortar's ability to fill the spaces and shafts in the concrete so that the concrete solidifies. Table 3 Slump test Result of fresh concrete containing CSP, with different w/c ratios. Composition CSP (%) wt. of FA 0 5 7 8 Avg. Slump Height (mm) of w/c Ratio 0.4 32 40 35 45 Avg. Slump Height (mm) of w/c Ratio 0.5 32 37 34 42 3.3 Mechanical Properties of CSP Concrete Table 4 shows the test results for mechanical concrete containing CSP, but it can be seen that normal concrete without CSP still has a higher value. A w/c ratio of 0.4 has a higher value than a w/c ratio of 0.5, where increasing w/c reduces the strength of concrete; this is in line with several studies (Yang et al., 2021 )(Abdalla et al., 2022 ). Concrete containing CSP is below the strength of normal concrete, but overall, concrete containing CSP has a strength above the design strength of 20 MPa, and the highest is SR-2. The difference between SR-2 and BN-1 is 9.9%; even SR-2 has the same strength as BN with a w/c ratio of 0.4 (BN-2). Calcium carbonate in concrete structures can reduce shafting (Ramalingam Malathy, Ragav Shanmugam, Ill-Min Chung, Seung-Hyun Kim, 2022). However, the calcium carbonate reaction is very slow in cement hydration (Calis et al., 2021 ). Table 4 Mechanical Properties of Concrete Containing CSP Sample Designation Percentage of Crab Shell Slump Compressive Strength SpliteTensile Strength Modulus of Elasticity Modulus of Rupture (% wt. of FA) (mm) (MPa) (MPa) (GPa) (MPa) SR-1 5 40 23.07 1.57 15009.31647 6.12 SR-2 7 35 25.96 1.52 13749.43611 6.36 SR-3 8 45 24.51 1.06 13726.48818 6.18 BN-1 - 32 28.84 1.80 18632.24478 6.71 TR-1 5 37 20.19 1.40 14885.75071 5.51 TR-2 7 34 23.07 1.37 14648.62214 6.24 TR-3 8 42 21.63 0.96 11865.64676 6.12 BN-2 - 32 25.96 1.74 16761.00814 6.69 3.4.Relation Among Compressive strength, W/C Ratio and Slump Figure 3 shows the relationship between compressive strength, w/c ratio, and slump in concrete containing CSP. The observation results indicate that the compressive strength value will increase with a decrease in the slump value. This situation applies to w/c ratios 0.4 and 0.5, but 0.4 has a higher value than 0.5. The pattern for concrete containing CSP shows a w/c ratio of 0.4, which is identical to 0.5. SR-2 increases compared to SR-1, SR-3, and TR-2 increases with TR-1 and TR-3. The 5% CSP content in concrete is a better composition. The strength of concrete is closely related to the material it forms and the condition of the concrete matrix when it is formed into concrete. This composition of 5% CSP can fill the space and increase the cement hydration reaction. SR-3 and TR-3 have excess calcium, so it is necessary to add pozzolan material, in line with previous studies (Li et al., 2019 ). 3.5 Compressive Strength and MoR Flexural strength is a concrete strength parameter that reflects resistance, pressure, and tensile. Flexural strength is more representative of the concrete conditions applied to the construction. The flexural strength of concrete is relatively very low compared to its compressive strength. But actually, there is a correlation between compressive strength and flexural strength in concrete. The higher the compressive strength of concrete, it shows an increase in its flexural strength (Nguyen et al., 2016 ). So, the focus of increasing the strength of concrete, including increasing the modulus of rupture of concrete, is how to increase the compressive strength of concrete. Figure 4 shows an increase in MoR in line with an increase in compressive strength. 4. Conclusions The presence of CSP as a sand substitute acts as a filler in empty spaces and increases the hydration of cement in the concrete matrix. Even though the hydration of calcium carbonate is slow, the strength of the concrete is guaranteed to continue to increase. The potential of CSP as a substitute for cement can be seen when the composition of 7% wt of cement with a w/c ratio has strength comparable to normal concrete at a w/c ratio of 0.5. The w/c ratio can also be seen in other properties of mechanical. Thus, further research on mixing CSP with concrete with other mixed ingredients is necessary to improve concrete performance. Declarations Author Contribution J. Hadipramana conceived of the presented idea, developed the theory and wrote the manuscript. F. V. Riza did the experiment in the lab and acted as the corresponding author. S. N. Mokhatar supervised the findings of this work. All authors discussed the results and contributed to the final manuscript Acknowledgement The authors would like to express their sincere appreciation to the Universitas Muhammadiyah Sumatera Utara (UMSU) for financial support at Internal Grant 2023, as well as to the Faculty of Engineering students and staff who generously shared References AASHTO T 19M/T 19-14. (2015). Standard Method of Test for Bulk Density ("Unit Weight") and Voids in Aggregate. Standard Specifications for Transportation Materials and Methods of Sampling and Testing , 2064–2072. Abdalla, J. A., Thomas, B. S., Hawileh, R. A., & Syed Ahmed Kabeer, K. I. (2022). Influence of nanomaterials on the workability and compressive strength of cement-based concrete. Materials Today: Proceedings , 65 , 2073–2076. https://doi.org/10.1016/j.matpr.2022.06.429 ASTM-C-128. (2003). Standard Test Method for Density, Relative Density (Specific Gravity), and Absorption of Fine Aggregate. In Annual Book of ASTM Standards (Vol. 88, Issue October 2001). https://doi.org/10.1203/01.PDR.0000175640.75468.D6 ASTM C-33-03, S. (2001). Standard Specification for Concrete Aggregates 1 (Vol. 04). ASTM C 127-01. (2001). Standard Test Method for Density, Relative Density (Specific Gravity), and Absorption. ASTM International , 1–6. www.astm.org, or Azra, M. N., & Ikhwanuddin, M. (2015). Larval culture and rearing techniques of commercially important crab, Portunus pelagicus (Linnaeus, 1758): Present status and future prospects. Songklanakarin Journal of Science and Technology , 37 (2), 135–145. Calis, G., Yildizel, S. A., Erzin, S., & Tayeh, B. A. (2021). Evaluation and optimisation of foam concrete containing ground calcium carbonate and glass fibre (experimental and modelling study). Case Studies in Construction Materials , 15 (April), e00625. https://doi.org/10.1016/j.cscm.2021.e00625 Camiletti, J., Soliman, A. M., & Nehdi, M. L. (2013). Effect of nano-calcium carbonate on early-age properties of ultrahigh-performance concrete. Magazine of Concrete Research , 65 (5), 297–307. https://doi.org/10.1680/macr.12.00015 Lertwattanaruk, P., Sua-iam, G., & Makul, N. (2018). Effects of calcium carbonate powder on the fresh and hardened properties of self-consolidating concrete incorporating untreated rice husk ash. In Journal of Cleaner Production (Vol. 172). Elsevier B.V. https://doi.org/10.1016/j.jclepro.2017.10.336 Li, L., Cao, M., & Yin, H. (2019). Comparative roles between aragonite and calcite calcium carbonate whiskers in the hydration and strength of cement paste. Cement and Concrete Composites , 104 (September 2018). https://doi.org/10.1016/j.cemconcomp.2019.103350 Matos, P. R. de, Foiato, M., & Prudêncio, L. R. (2019). Ecological, fresh state and long-term mechanical properties of high-volume fly ash high-performance self-compacting concrete. Construction and Building Materials , 203 , 282–293. https://doi.org/10.1016/j.conbuildmat.2019.01.074 Nguyen, K. T., Ahn, N., Le, T. A., & Lee, K. (2016). Theoretical and experimental study on mechanical properties and flexural strength of fly ash-geopolymer concrete. Construction and Building Materials , 106 , 65–77. https://doi.org/10.1016/j.conbuildmat.2015.12.033 Pavía, S., Walker, R., Veale, P., & Wood, A. (2014). Impact of the Properties and Reactivity of Rice Husk Ash on Lime Mortar Properties. Journal of Materials in Civil Engineering , 26 (9), 1–9. https://doi.org/10.1061/(asce)mt.1943-5533.0000967 Promsawat, P., Chatveera, B., Sua-iam, G., & Makul, N. (2020). Properties of self-compacting concrete prepared with ternary Portland cement-high volume fly ash-calcium carbonate blends. Case Studies in Construction Materials , 13 , e00426. https://doi.org/10.1016/j.cscm.2020.e00426 Ramalingam Malathy, Ragav Shanmugam, Ill-Min Chung, Seung-Hyun Kim, M. P. (2022). Mechanical and Microstructural Properties of Composite Mortars with Lime, Silica Fume and Rice Husk Ash . 10 (1424), 1–24. https://doi.org/https://doi.org/ 10.3390/pr10071424 Rashid, M. A., Mansur, M. A., Rashid M. A., & Mansur M. A. (2009). Considerations in producing high strength concrete. Journal of Civil Engineering (IEB) , 37 (1), 53–63. Raya, I., Mayasari, E., Yahya, A., Syahrul, M., & Latunra, A. I. (2015). Shynthesis and Characterizations of Calcium Hydroxyapatite Derived from Crabs Shells (Portunus pelagicus) and Its Potency in Safeguard against to Dental Demineralizations. International Journal of Biomaterials , 2015 . https://doi.org/10.1155/2015/469176 SNI-ASTM-C-136. (2012). SNI ASTM C 136-2012 Metode Uji Untuk Analisis Saringan Agregat Halus dan Agregat Kasar. In Badan Standardisasi Nasional (p. 24). https://pesta.bsn.go.id/produk/detail/9112-sniastmc1362012 SNI 03-2834. (2000). SNI 03-2834-2000: Tata cara pembuatan rencana campuran beton normal. Sni 03-2834-2000 , 1–34. Sua-Iam, G., & Makul, N. (2013). Utilization of limestone powder to improve the properties of self-compacting concrete incorporating high volumes of untreated rice husk ash as fine aggregate. Construction and Building Materials , 38 , 455–464. https://doi.org/10.1016/j.conbuildmat.2012.08.016 Yang, L., An, X., & Du, S. (2021). Estimating workability of concrete with different strength grades based on deep learning. Measurement: Journal of the International Measurement Confederation , 186 (May), 110073. https://doi.org/10.1016/j.measurement.2021.110073 Additional Declarations No competing interests reported. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-3904460","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Method Article","associatedPublications":[],"authors":[{"id":270252401,"identity":"f2ab03ea-166c-4594-a249-c653d8f647a3","order_by":0,"name":"Josef Hadipramana","email":"","orcid":"","institution":"Universitas Muhammadiyah Sumatera","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Josef","middleName":"","lastName":"Hadipramana","suffix":""},{"id":270252402,"identity":"83f4a317-fce5-456c-be94-7df01b9bbabf","order_by":1,"name":"Fetra Venny Riza","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAAuklEQVRIiWNgGAWjYBAC9gYQWQHnSzA2ENLCc4AZSJ4hWQtjG0KACC3s/cc+/Jx3OFp+RgLjhx8MFrKEtfAcZp7Zu+1w7oYbCcySPQwSxgS12EskMzPwgrRIJDBIA/2SSNgW+cfMjH/nHM6dPyOB+TdxWiSYmZl5Gw7nNtxIYCPSFp5kY2aZY+m5G848bLPsMSDCLzzsBx8zvqmxzp3fnnz4xo+KOsIhhgRAMWJAgvpRMApGwSgYBbgBAKe/OA7DnSsCAAAAAElFTkSuQmCC","orcid":"","institution":"Universitas Muhammadiyah Sumatera","correspondingAuthor":true,"submittingAuthor":false,"prefix":"","firstName":"Fetra","middleName":"Venny","lastName":"Riza","suffix":""},{"id":270252403,"identity":"d2c478ea-64e8-4ac4-bec5-aa3fc546d1dc","order_by":2,"name":"Shahrul Niza Mokhatar","email":"","orcid":"","institution":"Tun Hussein Onn University of Malaysia","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Shahrul","middleName":"Niza","lastName":"Mokhatar","suffix":""}],"badges":[],"createdAt":"2024-01-28 02:14:05","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-3904460/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-3904460/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":50475200,"identity":"a5fe7996-a77d-4f29-957a-db01a7081152","added_by":"auto","created_at":"2024-02-01 05:44:52","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":44368,"visible":true,"origin":"","legend":"\u003cp\u003eThe particle size distribution of FA based on ASTM C-33-03 shows FA is rough.\u003c/p\u003e","description":"","filename":"1.png","url":"https://assets-eu.researchsquare.com/files/rs-3904460/v1/cde287956376c094ded72970.png"},{"id":50475199,"identity":"75131fee-fb94-46e1-88cf-00e0dc708b1b","added_by":"auto","created_at":"2024-02-01 05:44:52","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":38787,"visible":true,"origin":"","legend":"\u003cp\u003eThe particle size gradation is close to the lower limit specified by ASTM C-139, indicating that the CA is rather smooth.\u003c/p\u003e","description":"","filename":"2.png","url":"https://assets-eu.researchsquare.com/files/rs-3904460/v1/07722b968eea8047c7d18267.png"},{"id":50475100,"identity":"9272451f-7199-4171-aace-265571677bc3","added_by":"auto","created_at":"2024-02-01 05:36:52","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":32942,"visible":true,"origin":"","legend":"\u003cp\u003eCorrelation among CSP composition, slump, and Compressive Strength\u003c/p\u003e","description":"","filename":"3.png","url":"https://assets-eu.researchsquare.com/files/rs-3904460/v1/a21e316b374e546fd1333771.png"},{"id":50475098,"identity":"5913097e-88b4-424c-b4f7-ffc9e9ff9bcf","added_by":"auto","created_at":"2024-02-01 05:36:52","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":41330,"visible":true,"origin":"","legend":"\u003cp\u003eRelation between compressive strength and MoR\u003c/p\u003e","description":"","filename":"4.png","url":"https://assets-eu.researchsquare.com/files/rs-3904460/v1/fd46b8e7f1c644035b861e4c.png"},{"id":50725625,"identity":"d185715d-4516-4730-9ede-d870e99c6b69","added_by":"auto","created_at":"2024-02-06 11:07:59","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":522005,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-3904460/v1/db95b23c-c0e8-477d-b43d-6000f8c78525.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Investigation of Crab (Portunus pelagicus) Shells in Concrete as a Potential Substitute for Fine Aggregate","fulltext":[{"header":"1. Introduction","content":"\u003cp\u003eMany studies use a variety of elements to supplement or replace concrete ingredients to achieve the best concrete strength performance. Using abandoned materials or debris that is cementitious and disrupts the environment is one alternative for increasing the strength of concrete to be more inexpensive and environmentally beneficial. Crab skin (Lat: Portunus Pelagicus) was chosen for this study because it contains Calcium Carbonate (CaCO3) in amounts ranging from 40\u0026ndash;70%, depending on the species variety. (Raya et al., \u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e2015\u003c/span\u003e). Crabs are extensively dispersed throughout Indo-Pacific waters, collected in open waters, or grown in aquaculture. (Azra \u0026amp; Ikhwanuddin, \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e2015\u003c/span\u003e). Indonesian crab export commodities yearly amounted to 604,215\u0026ndash;625,000 tons/year without the shell form. The figure can be calculated if the crab shells weigh up to 25% \u0026minus;\u0026thinsp;50% of the total weight of the crab (Raya et al., \u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e2015\u003c/span\u003e), then the potential waste of crab shells of 302,108\u0026ndash;312,50 tons can be generated per year.\u003c/p\u003e \u003cp\u003eThe addition of Calcium Carbonate (CC) in mortar can increase the workability, mechanical properties, and durability of the concrete (Sua-Iam \u0026amp; Makul, \u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e2013\u003c/span\u003e) (Lertwattanaruk et al., \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e2018\u003c/span\u003e). Using CC in mortar reduces the unit weight of concrete due to the specific gravity of CC being lower than cement (Promsawat et al., \u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e2020\u003c/span\u003e). If, in this study, CC partially replaced sand, then the volume of powdered material would increase due to the bulk density of CC being lesser than fine aggregate. The result is reduced segregation due to compaction. The shape and texture of CC and sand are very different, so mortar containing CC makes it easier to fill pores in concrete; hence, CC reduces intergranular friction (Matos et al., \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e2019\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eThe potential of CC to accelerate the setting and hardening of concrete performs very high by providing nucleation sites, increasing the contact points between materials and increasing the performance of the effective water-to-cement ratio (Camiletti et al., \u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e2013\u003c/span\u003e). Mechanical properties include compressive strength, split tensile strength, modulus of elasticity (MoE), and modulus of rupture (MoR), which are parameters needed in every concrete. Concrete in a loaded state under actual conditions bears pressure, tension, and torque variables. Therefore, the basic parameters affecting these variables must be met. The flexural strength of concrete acts against horizontal and vertical loads on concrete resists inertia loads, and resists moments that act at a certain point on concrete beams. Therefore, this study investigates the mechanical properties of concrete containing CSP as a potential new material that does not yet exist.\u003c/p\u003e"},{"header":"2. Materials and Methods","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003e2.1. Materials\u003c/h2\u003e \u003cp\u003eThe Indonesian Standard and ASTM (ASTM C 127-01, \u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e2001\u003c/span\u003e)(AASHTO T 19M/T 19\u0026thinsp;\u0026minus;\u0026thinsp;14, 2015)(ASTM-C-128, \u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e2003\u003c/span\u003e) were used to determine the feasibility test of fine (FA) and coarse (CA) aggregates in this study. The results of the material feasibility test are presented in Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e. The sieve analysis test obtained the Fineness Modulus (FM) (SNI-ASTM-C-136, \u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e2012\u003c/span\u003e). Several other tests are also performed, including density, bulk density, specific gravity, and absorption FA and CA. (ASTM C 127-01, \u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e2001\u003c/span\u003e)(ASTM-C-128, \u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e2003\u003c/span\u003e). This material test must be carried out because the material is a natural aggregate mined from downstream rivers, where there is a lot of dirt and mud. Crab skin powder is obtained using several processing processes. First, the skin is cleaned with water from organic residues and then dried in an oven at 80\u0026ordm;-90\u0026ordm;C for 12 hours. Heating is done by trial and error until it is obtained that the crab skin is free from organic residues. Next, the crab shells are crushed by pounding manually (crushing can be done using a machine) until the largest diameter passes through a 3/8-inch sieve. This is the largest diameter of sand, but the powder is finer than sand.\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 the constituent materials of concrete\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"6\"\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 \u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eProperties\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eCoarse Aggregate\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eLimitation\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eFine Aggregate\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eLimitation\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003eCement\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\u003eFineness Modulus (FM) (%)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e7.20\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e6\u0026ndash;7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e2.49\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e1.5\u0026ndash;3.8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eDensity (gr/cm\u003c/b\u003e\u003csup\u003e\u003cb\u003e3\u003c/b\u003e\u003c/sup\u003e\u003cb\u003e)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2.723\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e2.53\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e1.439\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eSpecific gravity (gr/cm\u003c/b\u003e\u003csup\u003e\u003cb\u003e3\u003c/b\u003e\u003c/sup\u003e\u003cb\u003e)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e3.102\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eBulk Density (gr/cm\u003c/b\u003e\u003csup\u003e\u003cb\u003e3\u003c/b\u003e\u003c/sup\u003e\u003cb\u003e)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1.31\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eMin. 1.125\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1.15\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eMax. 1.125\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eWater content (%)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0.67\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.5\u0026ndash;1.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e2.25\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e2.1\u0026ndash;2.3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eAbsorption (%)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0.777\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eMax. 4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1.83\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eMax. 2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eMud Content (%)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0.67\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eMax. 1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e3.67\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eMax. 5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eMaximum diameter (mm)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e40\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e2.36\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eAbrasion (%)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e16.460\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\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 \u003c/div\u003e \u003cdiv id=\"Sec4\" class=\"Section2\"\u003e \u003ch2\u003e2.2 Mix Design and Experimental Method\u003c/h2\u003e \u003cp\u003eThe concrete planning design uses the Indonesian National Standard (SNI 03-2834, \u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e2000\u003c/span\u003e). The proportions of each concrete are presented in Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e, where 2 series were made with different w/c ratios of 0.4 and 0.5. Each series has 4 variations in crab shell powder content of 5%, 7%, and 8% wt. of FA. One sample was made without crab shell powder (CSP) to compare and control for other variations. This investigation mix design uses 20 MPa design concrete.\u003c/p\u003e \u003cp\u003eMixing the mortar is like making normal concrete, namely first mixing the FA, cement, and crab shells powder so that it is mixed evenly for about 3 minutes. The CA is added and rotated for 1.5 minutes, and finally, the water is then rotated for 2 minutes until evenly mixed. The slump test is carried out to determine the workability of fresh concrete. Concrete samples are made in a cylindrical shape with a cross-sectional area of ​​\u0026Oslash; 150mm and a height of 300mm for compressive strength test, splitting tensile test, and modulus of elasticity. Meanwhile, the Modulus of Rupture is a prism with a cross-section of 150mm x 150mm and a length of 600mm. All samples were made in 5 pieces for each test.\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\u003eMix Proportion of Concrete containing CSP.\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"7\"\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=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSample\u003c/p\u003e \u003cp\u003eDesignation\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003ePercentage of Crab Shell\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eRatio of w/c\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eCement\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eFine Aggregate\u003c/p\u003e \u003cp\u003e(FA)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003eCoarse Aggregate\u003c/p\u003e \u003cp\u003e(CA)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c7\"\u003e \u003cp\u003eWater\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003e(% wt. of FA)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003e(Kg/m\u003csup\u003e3\u003c/sup\u003e)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003e(Kg/m\u003csup\u003e3\u003c/sup\u003e)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003e(Kg/m\u003csup\u003e3\u003c/sup\u003e)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c7\"\u003e \u003cp\u003e(Kg/m\u003csup\u003e3\u003c/sup\u003e)\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSR-1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0.4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e417.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e408.7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e1444.4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e167\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSR-2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0.4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e417.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e408.7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e1444.4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e167\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSR-3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0.4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e417.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e408.7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e1444.4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e167\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eBN-1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0.4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e417.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e408.7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e1444.4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e167\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTR-1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e334.0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e466.4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e1472.0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e167\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTR-2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e334.0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e466.4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e1472.0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e167\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTR-3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e334.0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e466.4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e1472.0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e167\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eBN-2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e334.0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e466.4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e1472.0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e167\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":"3. Results and Discussion","content":"\u003cdiv id=\"Sec6\" class=\"Section2\"\u003e \u003ch2\u003e3.1 Sieve Analysis\u003c/h2\u003e \u003cp\u003eThe dominant strength of concrete is formed from the aggregate that forms it, where the size of the aggregate can fill the spaces in the concrete mold. The aggregate gradation is important in concrete strength (Rashid et al., \u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e2009\u003c/span\u003e). Figures\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e and \u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e show the FA and CA gradations, respectively. Both aggregate particle size distributions are within the required (sufficient) range for each coarse and fine aggregate in accordance with the limits determined by ASTM C-33(ASTM C-33-03, \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e2001\u003c/span\u003e). Figures\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e shows that FA is in the rather coarse category, and Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e shows that the coarse aggregate is close to rather fine. This condition provides an advantage when the aggregate can fill the voids available in the concrete.\u003c/p\u003e\u003c/div\u003e \u003cdiv id=\"Sec7\" class=\"Section2\"\u003e \u003ch2\u003e3.2 Workability\u003c/h2\u003e \u003cp\u003eThe workability test on concrete containing CSP was carried out in the fresh state phase, with the results shown in Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e. The slump values ​​for both ratios are 30 to 45 mm, including in low slump. The w/c ratio of 0.4 has a greater value than the w/c ratio of 0.5. The ratios of w/c 0.4 and 0.5 have the highest slump values ​​of 45 mm and 42, respectively, at 8% CSP composition. The presence of CSP contributes to lowering the surface tension of the mortar, thereby increasing the slump value. Lime has a high water affinity because lime has a high interfacial surface area and lower superficial tension force (Pav\u0026iacute;a et al., \u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e2014\u003c/span\u003e). The consistency of the mixture and the cohesion of the materials in the mixture greatly influence workability. Workability affects strength because of the mortar's ability to fill the spaces and shafts in the concrete so that the concrete solidifies.\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\u003eSlump test Result of fresh concrete containing CSP, with different w/c ratios.\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=\"char\" char=\".\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eComposition CSP (%) wt. of FA\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003e7\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003e8\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\u003eAvg. Slump Height (mm) of w/c Ratio 0.4\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e32\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e40\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e35\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e45\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eAvg. Slump Height (mm) of w/c Ratio 0.5\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e32\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e37\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e34\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e42\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 Mechanical Properties of CSP Concrete\u003c/h2\u003e \u003cp\u003eTable\u0026nbsp;\u003cspan refid=\"Tab4\" class=\"InternalRef\"\u003e4\u003c/span\u003e shows the test results for mechanical concrete containing CSP, but it can be seen that normal concrete without CSP still has a higher value. A w/c ratio of 0.4 has a higher value than a w/c ratio of 0.5, where increasing w/c reduces the strength of concrete; this is in line with several studies (Yang et al., \u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e2021\u003c/span\u003e)(Abdalla et al., \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2022\u003c/span\u003e). Concrete containing CSP is below the strength of normal concrete, but overall, concrete containing CSP has a strength above the design strength of 20 MPa, and the highest is SR-2. The difference between SR-2 and BN-1 is 9.9%; even SR-2 has the same strength as BN with a w/c ratio of 0.4 (BN-2). Calcium carbonate in concrete structures can reduce shafting (Ramalingam Malathy, Ragav Shanmugam, Ill-Min Chung, Seung-Hyun Kim, 2022). However, the calcium carbonate reaction is very slow in cement hydration (Calis et al., \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e2021\u003c/span\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\u003eMechanical Properties of Concrete Containing CSP\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"7\"\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=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSample\u003c/p\u003e \u003cp\u003eDesignation\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003ePercentage of Crab Shell\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eSlump\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eCompressive Strength\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eSpliteTensile Strength\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003eModulus of Elasticity\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c7\"\u003e \u003cp\u003eModulus of Rupture\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003e(% wt. of FA)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003e(mm)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003e(MPa)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003e(MPa)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003e(GPa)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c7\"\u003e \u003cp\u003e(MPa)\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSR-1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e40\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e23.07\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e1.57\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e15009.31647\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e6.12\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSR-2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e35\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e25.96\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e1.52\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e13749.43611\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e6.36\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSR-3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e45\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e24.51\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e1.06\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e13726.48818\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e6.18\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eBN-1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e32\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e28.84\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e1.80\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e18632.24478\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e6.71\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTR-1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e37\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e20.19\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e1.40\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e14885.75071\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e5.51\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTR-2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e34\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e23.07\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e1.37\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e14648.62214\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e6.24\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTR-3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e42\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e21.63\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.96\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e11865.64676\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e6.12\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eBN-2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e32\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e25.96\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e1.74\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e16761.00814\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e6.69\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=\"Sec9\" class=\"Section2\"\u003e \u003ch2\u003e3.4.Relation Among Compressive strength, W/C Ratio and Slump\u003c/h2\u003e \u003cp\u003eFigure \u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e shows the relationship between compressive strength, w/c ratio, and slump in concrete containing CSP. The observation results indicate that the compressive strength value will increase with a decrease in the slump value. This situation applies to w/c ratios 0.4 and 0.5, but 0.4 has a higher value than 0.5. The pattern for concrete containing CSP shows a w/c ratio of 0.4, which is identical to 0.5. SR-2 increases compared to SR-1, SR-3, and TR-2 increases with TR-1 and TR-3. The 5% CSP content in concrete is a better composition. The strength of concrete is closely related to the material it forms and the condition of the concrete matrix when it is formed into concrete. This composition of 5% CSP can fill the space and increase the cement hydration reaction. SR-3 and TR-3 have excess calcium, so it is necessary to add pozzolan material, in line with previous studies (Li et al., \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e2019\u003c/span\u003e).\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec10\" class=\"Section2\"\u003e \u003ch2\u003e3.5 Compressive Strength and MoR\u003c/h2\u003e \u003cp\u003eFlexural strength is a concrete strength parameter that reflects resistance, pressure, and tensile. Flexural strength is more representative of the concrete conditions applied to the construction. The flexural strength of concrete is relatively very low compared to its compressive strength. But actually, there is a correlation between compressive strength and flexural strength in concrete. The higher the compressive strength of concrete, it shows an increase in its flexural strength (Nguyen et al., \u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e2016\u003c/span\u003e). So, the focus of increasing the strength of concrete, including increasing the modulus of rupture of concrete, is how to increase the compressive strength of concrete. Figure\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e shows an increase in MoR in line with an increase in compressive strength.\u003c/p\u003e\u003c/div\u003e"},{"header":"4. Conclusions","content":"\u003cp\u003eThe presence of CSP as a sand substitute acts as a filler in empty spaces and increases the hydration of cement in the concrete matrix. Even though the hydration of calcium carbonate is slow, the strength of the concrete is guaranteed to continue to increase. The potential of CSP as a substitute for cement can be seen when the composition of 7% wt of cement with a w/c ratio has strength comparable to normal concrete at a w/c ratio of 0.5. The w/c ratio can also be seen in other properties of mechanical. Thus, further research on mixing CSP with concrete with other mixed ingredients is necessary to improve concrete performance.\u003c/p\u003e"},{"header":"Declarations","content":"\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\u003cp\u003eJ. Hadipramana conceived of the presented idea, developed the theory and wrote the manuscript. F. V. Riza did the experiment in the lab and acted as the corresponding author. S. N. Mokhatar supervised the findings of this work. All authors discussed the results and contributed to the final manuscript\u003c/p\u003e\u003ch2\u003eAcknowledgement\u003c/h2\u003e \u003cp\u003eThe authors would like to express their sincere appreciation to the Universitas Muhammadiyah Sumatera Utara (UMSU) for financial support at Internal Grant 2023, as well as to the Faculty of Engineering students and staff who generously shared\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eAASHTO T 19M/T 19-14. (2015). 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Evaluation and optimisation of foam concrete containing ground calcium carbonate and glass fibre (experimental and modelling study). \u003cem\u003eCase Studies in Construction Materials\u003c/em\u003e, \u003cem\u003e15\u003c/em\u003e(April), e00625. https://doi.org/10.1016/j.cscm.2021.e00625\u003c/li\u003e\n\u003cli\u003eCamiletti, J., Soliman, A. M., \u0026amp; Nehdi, M. L. (2013). Effect of nano-calcium carbonate on early-age properties of ultrahigh-performance concrete. \u003cem\u003eMagazine of Concrete Research\u003c/em\u003e, \u003cem\u003e65\u003c/em\u003e(5), 297\u0026ndash;307. https://doi.org/10.1680/macr.12.00015\u003c/li\u003e\n\u003cli\u003eLertwattanaruk, P., Sua-iam, G., \u0026amp; Makul, N. (2018). Effects of calcium carbonate powder on the fresh and hardened properties of self-consolidating concrete incorporating untreated rice husk ash. In \u003cem\u003eJournal of Cleaner Production\u003c/em\u003e (Vol. 172). 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SNI 03-2834-2000: Tata cara pembuatan rencana campuran beton normal. \u003cem\u003eSni 03-2834-2000\u003c/em\u003e, 1\u0026ndash;34.\u003c/li\u003e\n\u003cli\u003eSua-Iam, G., \u0026amp; Makul, N. (2013). Utilization of limestone powder to improve the properties of self-compacting concrete incorporating high volumes of untreated rice husk ash as fine aggregate. \u003cem\u003eConstruction and Building Materials\u003c/em\u003e, \u003cem\u003e38\u003c/em\u003e, 455\u0026ndash;464. https://doi.org/10.1016/j.conbuildmat.2012.08.016\u003c/li\u003e\n\u003cli\u003eYang, L., An, X., \u0026amp; Du, S. (2021). Estimating workability of concrete with different strength grades based on deep learning. \u003cem\u003eMeasurement: Journal of the International Measurement Confederation\u003c/em\u003e, \u003cem\u003e186\u003c/em\u003e(May), 110073. https://doi.org/10.1016/j.measurement.2021.110073\u003c/li\u003e\n\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":"crab, shell, calcium-carbonate, hydration, cement ","lastPublishedDoi":"10.21203/rs.3.rs-3904460/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-3904460/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eBlue crab shell (Portunus pelagicus) is a fairly abundant domestic waste in the Indo-Pacific and has the potential to be reused. This study aimed to take advantage of the benefit of crab shells, which contain a lot of calcium carbonate and can potentially help the cement hydration reaction to create concrete strength. This study analyzed the mechanical properties of concrete containing crab shell powder (CSP). The composition of crab shell powder as a substitute for fine aggregate (FA) with variations of 5%, 7%, and 8% wt. FA. Crab shells (CS) are dried and finely crushed with a diameter of 1/8 inch, or equivalent to the diameter of FA. This study uses w/c ratios of 0.4 and 0.5 and all aggregates in SSD condition. The results show that the compressive strength of concrete containing CSP is above the strength of the design concrete. The composition of 5% CSP at a w/c ratio of 0.4 is equivalent to the strength of normal concrete with a w/c of 0.5%. The result showed the potential for CSP to replace fine aggregate while helping the cement hydration process.\u003c/p\u003e","manuscriptTitle":"Investigation of Crab (Portunus pelagicus) Shells in Concrete as a Potential Substitute for Fine Aggregate","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2024-02-01 05:36:47","doi":"10.21203/rs.3.rs-3904460/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":"00755a58-d3ef-463c-8d13-d517fb42dd32","owner":[],"postedDate":"February 1st, 2024","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2024-02-06T10:59:52+00:00","versionOfRecord":[],"versionCreatedAt":"2024-02-01 05:36:47","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-3904460","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-3904460","identity":"rs-3904460","version":["v1"]},"buildId":"rHA-KDH7Qsr4HCuvH75dn","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}