Research on the mix proportion and on-site construction technology of a four-graded roller compacted concrete

Research on the mix proportion and on-site construction technology of a four-graded roller compacted 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 Research on the mix proportion and on-site construction technology of a four-graded roller compacted concrete Yan Shi, Shihua Zhou, Cai Wu, Junzhou Huang, Yan Liang, Tianlei Wang, and 2 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-4290682/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 In order to improve construction and production efficiency, and fully leverage the technical and economic advantages of continuous pouring and rapid rise of roller compacted concrete, the four-graded roller compacted concrete was widely used in hydraulic engineering. Based on the characteristics and testing methods of four-graded roller compacted concrete, the multiple sets, the effects of mix proportion, maximum particle size of coarse aggregate, and compaction degree were analyzed. The differences in construction technology between three-graded roller compacted concrete and four-graded roller compacted concrete were compared, and the more suitable construction technology parameters for four-graded roller compacted concrete were obtained. When the water consumption and vibrating compacted (VC) value are within the range of 71kg/m³~70kg/m³ and 3.5s ~ 6s, respectively, the VC value and air content of four-graded roller compacted concrete are optimal. Choose 30%~32% for sand ratio. The combination ratio of natural coarse aggregates (extra large: large: medium: small) adopts 25: 30: 25: 20. The VC value of 3.5s is suitable. After 6 times of heavy rolling and vibration rolling, the surface has a good slurry state, with a relative compaction degree exceeding 98%. The vibration force is 395kN, and the working speed is 1.0 ~ 1.5km/h. The suggestions as follows: when the layer thickness is 0.4m, the four-graded roller compacted concrete should be rolled twice without vibration, six times with vibration, and two times without vibration; When the layer thickness is 0.5m, the four-graded roller compacted concrete should be rolled twice without vibration, eight times with vibration, and two times without vibration. Four-graded roller compacted concrete vibrating compacted (VC) value natural coarse aggregates construction technology mix proportion Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 1. Introduction Since the 1970s, roller compacted concrete had appeared in experimental research in the field of dam construction, which adopted a method that combines the structural characteristics of normal concrete dams with the construction technology of earth-rock dams (Jia et al. 2006 ). Roller compacted concrete has the advantages of low hydration heat, zero slump, and low cost, making it suitable for constructing large dam structures (Luo et al. 2022 ). Roller compacted concrete dams combine the structural advantages of traditional concrete dams with the construction technology of earth-rockfill dams, resulting in lower construction costs, higher equipment utilization efficiency, and easier and faster construction compared to traditional concrete dams (Selvam et al. 2022 ). During the construction of roller compacted concrete dams, the combined action of strong mechanical vibration and rolling compaction was used to compact ultra dry and hard concrete. Due to the layered compaction during construction, there are often many horizontal construction joints in the roller compacted concrete dam, forming numerous horizontal layers (Shen et al. 2001). In experimental research and construction practice (Pacelli et al. 1993 ; Shen et al. 2023 ; Liu et al. 2018 ), it was found that the quality of interlayer bonding had a significant impact on the performance of the roller compacted concrete dam. Different material ratios, different material parameters, and unsuitable rolling construction techniques can cause local defects in the layer, which affects the stability of layer stress and the performance of the dam body. The adhesiveness of roller compacted concrete mixtures was very poor, and it was easy to cause aggregate separation during transportation and paving. After rolling, it may also result in non compaction, which affects the overall impermeability of the dam (Huang et al. 2017 ). To reduce or avoid the phenomenon of coarse aggregate separation, in some projects, the maximum particle size and proportion of coarse aggregate are limited, and second-graded or third-graded roller compacted concrete was selected (Jia et al. 2006 ). Increasing the maximum particle size of coarse aggregate can lessen the porosity of coarse aggregate and require less cementitious material overall. Therefore, how to find the balance point between the two requires extremely detailed experimental determination. Increasing the maximum particle size of coarse aggregate can reduce the porosity of coarse aggregate and reduce the amount of cementitious material used. The maximum particle size of crushed stone is usually limited to below 80mm (Huang et al. 2017 ). Appropriate aggregate gradation and the ratio of coarse and fine aggregates are key factors in obtaining high-performance roller compacted concrete. The correct selection of aggregates will minimize voids, reduce segregation, and affect water demand. Therefore, determining the maximum size of aggregates and the ratio of coarse and fine aggregates is crucial. Hashemi et al. ( 2018 ) investigated the impact of coarse to fine (C/F) aggregate ratio on the performance of two types of roller compacted concretes with cement contents of 9% and 12%, and mechanical performance tests were conducted to determine the hardening performance of roller compacted concrete. The experimental results indicated that increasing the C/F ratio from 0.6 to 1.8 tripled the Vebe time, while increasing the C/F ratio from 0.6 to 1.2 obviously reduced the porosity, and with the increase of the C/F ratio or cement content, the compressive, splitting tensile and bending tensile strengths of the specimens remarkably increased; Li et al. ( 2015 ) analyzed the stress and seepage fields of a roller compacted concrete dam with three-graded roller compacted concrete and two-graded roller compacted concrete, and found that the impermeable layer constructed with three-graded roller compacted concrete has comparatively poor permeability resistance, while two-graded roller compacted concrete can improve its permeability resistance but may form seepage channels; Wu et al. ( 2013 ) tested the combined compressive properties of concrete specimens with different sizes from 150 mm to 600 mm and found that the compressive strength decreased with the increase of cube size; Mohammed et al. (2020) completely redesigned the concrete mixture based on the maximum size of coarse aggregate and selected different types of mixtures for experimental comparison to research the impact of maximum aggregate size on the strength of normal and high-strength concrete and it was spotted that the compressive strength increased with the increase in the maximum size of coarse aggregate; based on the results obtained from experimental studies, Saouma et al. ( 1991 ) and Li et al. ( 2004 ) spotted that the tensile strength of dam concrete decreases with increasing aggregate size; Rao et al. ( 2016 ) conducted a study to investigate the influence of aggregate particle size on the mechanical property of roller compacted concrete through the full-graded and wet sieve method test to comprehensively explore the impact of coarse aggregate’s grain size. The effect of coarse aggregate particle on the stability of roller compacted concrete in dams construction was also examined. The study provided technical support for the application of full gradation roller compacted concrete in practical engineering. It found that as the content of large-sized aggregates in full gradation concrete specimens increased, the air content of the concrete decreased, thereby improving the compressive strength, but larger maximum aggregate size resulted in poorer impermeability of concrete; Zhang et al. ( 2020 ) mixed different contents of macadam into four graded roller compacted concrete with a maximum grain size of 120 mm. They carried out mechanical properties and freeze-thaw cycles tests, and based on the test data, established a quantitative relationship between the gravel content and various mechanical properties, as well as the degree of damage, and developed a freeze-thaw damage model; Yang et al. ( 2016 ) found in the experiment that the reduction in the maximum particle size of macadam in fully graded concrete slightly reduces its compressive strength but slightly increases its tensile strength; Research into the microstructure of four graded roller compacted concrete (He et al. 2018 ) has shown that larger-size aggregates lead to more free water being adsorbed, which can have an effect on cement hydration as well as porosity, and then has a major impact on mechanical properties of concrete. The compaction quality of roller compacted concrete is one of the key factors affecting its performance, and friction is generated in the aggregates during compaction, so the performance of roller compacted concrete has a close relationship with the aggregates used, and at the same time, it is also related to the relative compaction of vibration rolling of concrete, and the construction parameters and the number of times of rolling during compaction affect the relative compaction of concrete (Aghaeipour et al. 2020) , and controlling the compaction quality of layers is the key to ensuring the quality of the project.According to the development and research results of early roller compacted concrete(Hansen and Reinhardt 2000 ), the crucial points impacting bonding strength of interlamination of roller compacted concrete are summarized, including the impact of the compaction effect of the upper layer of roller compacted concrete on the interlayer adhesive force: the upper layer of compacted concrete will reduce the concrete void ratio at the layer, forming a good bond, when the rolling is not compacted or the aggregate separation at the layer, it will make the concrete void ratio at the level increase significantly, leading to a reduction in the bonding strength of interlamination. When compaction is not compacted or aggregate separation occurs at the layer, the void ratio of concrete at the layer will increase significantly, leading to a reduction in interlayer adhesive force. Insufficient or excessive compaction will lead to deterioration of the concrete performance, which will have an impact on the integral stability or anti-seepage effect of the dam, and affect the healthy operation of the dam; the current research on rolling parameters includes the role of different rolling parameters in vibratory compacted (VC) (Kokubu et al. 1996 ), the monitoring method of rolling parameters(Zhong et al. 2009 ; Zhong et al. 2011 )and the compaction quality control technology based on rolling parameters (Liu et al. 2012 ). Liu et al. (Liu et al. 2015 ) used the unit compaction energy index to quantify the quality of roller compacted concrete dams; Godoi et al. ( 2019 ) improved the technique of using conventional X-ray imaging to detect the compaction degree of compacted layers. Compared with conventional concrete, roller compacted concrete requires more aggregates for compaction and consolidation. Both the degree of compaction and the number of rolling vibrations needed during construction are impacted (Harrington et al. 2010 ; Delatte et al. 2006); Xu et al. ( 2022 ) analyzed the compaction mechanism and established a compaction quality control system based on the results of on-site experiments, obtained economic and efficient compaction quality parameters to meet the construction quality control and rapid mechanized construction, and verified their reliability; Amer et al. ( 2004 ) Compaction of roller compacted concrete mixtures to different densities using the rotary compactor and experimental study on the improvement of roller compacted concrete mix proportion using rotary compactor; Williams et al. (2013) and Amer et al. ( 2003 ) compared the compaction densities and mechanical properties of roller compacted concrete compacted using the Proctor compaction methods with those compacted using gyratory compaction method, and found that the gyratory compaction method produced significantly higher densities at higher water contents; Selvam et al. ( 2023 ) in a comprehensive investigation found that the main factors affecting aggregate distribution are the ratio of aggregates to mortar, particle spacing, and compaction method. The compaction method plays a crucial role in the formation of the internal structure of roller compacted concrete. After conducting compaction tests on the samples using multiple compaction methods, it was found that the maximum density and compressive strength in the samples were compacted using the vibrating hammer; Şengün et al. ( 2018 ; 2019 ) used four laboratory compaction methods for the compaction of roller compacted concrete of two mix proportions and found that as the VeBe time increased, the difference in compaction coefficients obtained from specimens compacted using different compaction methods increased. Using a vibrating hammer for compaction can make specimens with low cement content have higher density and strength values. The strength and density of samples compacted using a rotary compactor are more similar to the actual engineering situation; Zhao et al. ( 2021 ) modeled the change of compaction energy density with compaction degree, quantified the compaction energy density and proposed a new method for compaction program development and adjustment of the number of rolling times. Fracture toughness (K IC and CTOD C ) is an important parameter in determining the performance of ultra-high arch dams; Sengun et al. ( 2021 ) designed seven different mixtures to study the fracture characteristics of roller compacted concrete in their experiment. The experimental results showed that as the maximum aggregate particle size and compaction coefficient of aggregates increased, the fracture parameters also increased. With the development of dam building technology in recent years, four-graded roller compacted concrete has gradually been considered and applied in actual projects, its research and use have imcreased the maximum particle size of aggregate, saved water consumption, further reduced the amount of mortar and cementitious materials of roller compacted concrete (Golewski and Sadowski, 2016 ), improved the crack resistance performance, and fully utilized its technical and economic advantages (Lindquist et al. 2014). However, due to the increase in aggregate particle size, it may cause problems such as aggregate separation or internal defects in concrete, and may also affect the compaction effect of vibratory milling and thus affect the structural impermeability of the dam and the performance of the mix (Hashemi et al. 2018 ). Roller compacted concrete requires proper compaction methods to achieve the required engineering properties, improved compaction increases the load carrying capacity and thus the service life of the project (Selvam et al. 2023 ). The dense accumulation of aggregates in roller compacted concrete mixture helps to achieve higher compressive strengths (Selvam et al. 2022 ). The use of a four-graded roller compacted concrete instead of a three-stage roller compacted concrete leads to a reduction in the dosage of cementitious materials, and a reduction in the hydration temperature rise is reduced, which can effectively simplify the temperature control measures, increase the paving layer thickness in construction, reduce the level, improve the construction speed and productivity, and give full play to the technical and economic advantages of continuous pouring and rapid rise of the roller compacted concrete (2016). However, there are not many researches on the four-graded distribution of roller compacted concrete, and many aspects of the technical information have certain limitations or are almost blank. The water-cement ratio and aggregate proportion, as well as the choice of construction technology, all affect the performance of the roller compacted concrete. This paper analyzes the above problems experimentally to provide a reference for the choice of water consumption, sand rate, coarse aggregate proportion and construction technology of four-graded roller compacted concrete. 2. Analysis of mix proportion of four-graded roller compacted concrete 2.1 Cement The cement is 42.5 ordinary Portland cement, which is produced by Chongqing Maotian. The physical and mechanical properties of cement are shown in Table 1 . Table 1 Physical and mechanical properties of cement Fineness (%) Apparent density (m 2 /kg) Density (kg/m 3 ) Consistence (%) Stability Setting time Compressive strength Bending strength Initial setting Final setting 3d 7d 28d 3d 7d 28d 2.0 405 3100 25.8 qualified 1:30 2:33 32.4 42.4 53.6 5.6 6.8 7.7 2.2 Fly ash Fly ash is produced by Guizhou Dalong Power Plant, with a specific surface area of 352m 2 /kg and a water demand ratio of 95%. It has been tested to meet the standard of Class II fly ash in GB 1596-91 . 2.3 Admixture HLC-NAF retarder and high-efficiency water reducing agent, produced by Nanjing Ruidi High-tech Company; the air entraining agent is produced by Shanxi Sangmusi Building Materials Chemical Co., Ltd. 2.4 Aggregate materials The fineness modulus of the artificial sand is F.M = 2.72 and the stone dust content is 14.2%. 2.5 Specimen design and preparation According to the "Technical specification for hydraulic roller compacted concrete process test" (DL/T 5804 − 2019, 2019), the water cement ratio (w/c) is taken as 0.50, the water consumption is set to 70kg/m³, 71kg/m³, 72kg/m³, 73kg/m³, 74kg/m³, and 78kg/m³, the fly ash content is taken as 55% and 60%, and the sand rate is set to 28%, 30%, 32%, and 34%. The admixtures for roller compacted concrete include water reducing agents and air entraining agents, with a water reducing agent value of 0.7% and an air entraining agent value of 0.05 and 0.06. The compacted density of the stone is 1860kg/m³, and the combination ratio values are 0:30:40:30 and 20:30:30:30:20. TGR and FGR represent third-graded and fourth-graded roller compacted concrete, respectively, with the following numbers indicating the sample number. Table 2 Specimens design details Specimen w/c water consumption (kg/m 3 ) Fly ash dosage (%) Sand rate (%) Admixture Natural coarse aggregate FGR compacted concrete Superplas-ticizer (%) Air entrain admixture (%) Combination ratio (Extra large: Large: Medium: Small) Tap density (kg/m 3 ) VC value (s) Gas content (%) Compacted wet density (kg/m 3 ) TGR-0 0.50 78 55 34 0.7 0.06 0:30:40:30 1860 3.5 4.0 2630 FGR-1 0.50 70 60 30 0.7 0.05 20:30:30:20 1860 5.9 4.5 2438 FGR-2 0.50 72 60 30 0.7 0.05 20:30:30:20 1860 4.7 3.9 2438 FGR-3 0.50 74 60 30 0.7 0.05 20:30:30:20 1860 2.9 2.4 2438 FGR-4 0.50 72 60 28 0.7 0.05 20:30:30:20 1860 4.4 3.7 2438 FGR-5 0.50 72 60 32 0.7 0.05 20:30:30:20 1860 4.9 4.1 2438 FGR-6 0.50 71 60 30 0.7 0.05 20:30:30:20 1860 3.5 3.1 2438 FGR-7 0.50 73 60 32 0.7 0.05 20:30:30:20 1860 2.6 3.1 2438 FGR-8 0.50 73 60 30 0.7 0.06 20:30:30:20 1860 4.6 3.7 2438 FGR-9 0.50 72 60 30 0.7 0.05 25:30:25:20 1860 4.0 4.0 2438 FGR-10 0.50 71 60 30 0.7 0.05 20:30:30:20 1860 5.3 4.2 2438 FGR-11 0.50 72 60 30 0.7 0.05 30:30:30:20 1860 3.2 4.3 2438 2.6 Experimental setup and program According to the proportioning design in 4 times to add materials, first add sand, stone, mix well and then add admixture, then 2/3 water and water reducing agent stir are added and stirred well, finally add 1/3 water. After weighing the raw materials, mix them well in the mixer. The production of the test specimen of roller compacted concrete was produced at the Shatuo Hydropower Station, using the method of insertion pounding and pouring, vibration compacting, by loading the materials in layers, inserting the pounding rod into the uniform insertion pounding after the completion of loading in each layer, and finally completing it by using the concrete roller to finish the compacting. The length of the test specimen is 30m, the width is 15m, and the thickness is 2.3m. According to the design scheme in Table 2 , the rolling area is divided into the comparative rolling area and the test rolling area, the comparative rolling area is TGR, and the test rolling area is the FGR. The on-site construction process test arrangement of roller compacted concrete is shown in Fig. 1 . The longitudinal arrangement of the on-site construction process along the thickness direction of the test specimen includes 5 layers. From the bottom up, there are layers 1 to 5, with a total thickness of 2.3m. The thickness of the first layer is 0.4m, and a test combination of optimal VC value and optimal compaction frequency is adopted; The thickness of the second and third layers is both 0.5m, and the optimal VC value and different compaction times are used as experimental combinations; The thickness of the fourth layer is 0.4m, and a combination of 3 ~ 5s VC value and different compaction times is used for testing; The thickness of the fifth layer is 0.5m, and a combination of VC values of 1 ~ 3s and different rolling times is adopted. The concrete mixture that has passed the performance test at the outlet of the mixing plant shall be transported by a 20T dump truck to the test block for performance and compaction process testing of the mixture. The performance of concrete mixtures includes VC value, apparent density test, as well as evaluation of aggregate separation and wrapping; By conducting compaction process experiments, the relationship between VC value, compacted layer thickness, compaction frequency, relative compaction, and excitation force was obtained, and recommended construction process parameters for FGR were proposed. 3. Analysis of on-site construction parameters 3.1 Water consumption (%) When other parameters are kept consistent, the water consumption has a significant impact on the VC value and air content of FGR. Therefore, specimens TGR-0, FGR-1, FGR-2, FGR-3, and FGR-10 were selected for research, and the water consumption diagram shown in Fig. 2 was drawn. From Fig. 2a, it can be seen that when the water consumption is 74kg/m³, the VC value of specimen FGR-3 is the smallest, indicating excess water; When the VC value is set to 4s ~ 6s, the water consumption is 72kg/m³~70kg/m³. Compared with the TGR-0 specimen, the water consumption can be reduced by 8kg/m³~10kg/m³, saving 16kg/m³~20kg/m³ of cementitious material. From Fig. 2b, it can be seen that compared with specimen TGR-0, specimen FGR-1 and specimen FGR-10 have higher air content, which can effectively reduce the viscosity of FGR, which is beneficial for improving overall working performance and construction efficiency. In summary, it can be seen that when the water consumption is not higher than 73kg/m³, the VC value of FGR will be better than that of TGR; When the water consumption is not higher than 71kg/m³, the air content of FGR will be better than that of TGR. Therefore, it is recommended to control the water consumption of FGR within the range of 71kg/m³ to 70kg/m³, where the VC value and air content are optimal. (a) VC value (s) (b) Gas content (%) Figure 2 Diagram of water consumption (%) for FGR 3.2 Sand rate (%) Figure 3 shows the influence mechanism of sand rate on the VC value and air content of FGR. When the sand rate is different, the VC values of specimen TGR-0 are all lower than those of specimen FGR-2, specimen FGR-4, and specimen FGR-5, indicating that the sand rate proposed in this paper can be used for FGR. In FGR, as the sand rate increases, the VC value and air content both increase slightly. Within the range of sand rate of 28–32%, the influence of sand rate on the VC value and air content of FGR is not significant. In Fig. 3(b), the gas content of specimen TGR-0 is only lower than that of specimen FGR-4. In addition, there is no phenomenon of increasing the VC value at a sand content of 28%. This is because roller compacted concrete contains more sand than normal concrete does. In addition, the VC value test is different from the slump test. From the appearance of the mixture, it is more appropriate to choose a sand rate of 30–32% for FGR, which is consistent with the commonly used sand rate of 34% for TGR. (a) VC value (s) (b) Gas content (%) Figure 3 Diagram of sand rate (%) for FGR 3.3 Combination ratio of natural coarse aggregates (Extra large: Large: Medium: Small) The "Technical specification for hydraulic roller compacted concrete process test" (DL/T 5804 − 2019, 2019) provides a combination ratio of natural coarse aggregates (extra large: extra large: extra medium: extra small) for TGR, which is 0:30:40:30. The mass percentage of extra large natural coarse aggregates is 0, indicating that extra large natural coarse aggregates are not necessary in the performance analysis of TGR. The combination ratio of natural coarse aggregates for FGR (extra large: large: medium: small) is 20:30:30:20, 25:30:25:20, and 30:30:30:20, respectively. The ratio of extra large natural coarse aggregates to medium natural coarse aggregates is 2/3, 1 and 1, respectively, indicating that the extra large and medium particle sizes of natural coarse aggregates have a noteworthy effect on the performance of FGR. The impact of three natural coarse aggregate combinations on the VC value and air content of FGR are studied in this article, aiming to reveal the relationship between the natural coarse aggregate combination ratio, VC value, and air content, and obtain a suitable natural coarse aggregate combination ratio (large: large: medium: small) for the widespread application of FGR. According to Fig. 4, when the natural coarse aggregate combination ratio (extra large: large: medium: small) is 20:30:30:20 and 25:30:25:20, the VC values of specimens FGR-2 and FGR-9 are larger than those of specimens TGR-0, with an increase range of 14.29–34.29%; When other parameters are the same, the gas content of specimens FGR-9 and FGR-11 is not less than that of specimen TGR-0, with a growth range of 0-7.5%. In order to meet the requirements of the "Technical specification for hydraulic roller compacted concrete process test" (DL/T 5804 − 2019, 2019) and ensure that the performance of FGR is not inferior to that of TGR, it is recommended to use a ratio of 25:30:25:20 for the combination of natural coarse aggregates (extra large: large: medium: small). (a) VC value (s) (b) Gas content (%) Figure 4 Diagram of Combination ratio of natural coarse aggregates for FGR 3.4 Aggregate coating and resistance to segregation In order to determine the workability of the FGR mixture, a 20T dump truck was used to directly store the material and complete the unloading in one go. The measured accumulation of the mixture was recorded in Table 3 . As can be seen from Table 3 , both specimen FGR-6 and specimen FGR-7 had good coated large aggregates in the FGR mixes. The number of rolled aggregates in the mixing material pile of FGR is higher than that of TGR. The direct reason for the separation of aggregate particles in the concrete mixture during the unloading process is due to the displacement caused by different movements between the aggregates. When changing from motion to rest, the relative displacement of the aggregate to the surrounding mix is positively correlated to the square of the particle radius, the density and the initial relative velocity, and varies inversely with the viscosity coefficient of the mix (Lin et al. 2011 ). Improving the separation resistance of FGR can be achieved in the following ways: a proper mixing proportion can be used to improve the cohesion of the concrete mixture, supplemented by other measures such as reducing the number of times the mixture is transported, reducing the height of unloading and material piles, using large pavers, and manually dispersing the large aggregates concentrated due to separation, which can effectively prevent or reduce the separation of aggregates in FGR, Improve the uniformity of roller compacted concrete mixtures and the quality. Table 3 Parameters of FGR roller compacted concrete mixture windrower Specimen VC value (s) Volume /m 3 Pile height /m Land occupation of material piles /m 2 Number of large aggregate roll-offs /piece Aggregate coating condition TGR-0 3.5 9 1.33 4.0×3.0 8 good FGR-6 3.5 9 1.23 5.0×2.8 22 Relatively good FGR-7 2.6 9 1.28 4.8×2.9 19 Relatively good 3.5 VC characteristics of mixtures The process test of FGR adopts the YZ20C type fully hydraulic single steel wheel vibration roller produced by Sany Group. The weak vibration represents the excitation force of the vibrating roller as 280kN, while the strong vibration represents it as 395kN. Table 4 contains the findings from the roller compacted concrete's apparent density and relative compaction tests. The experimental results show that the surface of the FGR mixture with a VC value of 2.6s is prone to bleeding after being compacted 6 times with a weak vibration. However, the relative compaction of the concrete at this point was only about 92%. The surface of the FGR mixture with a VC value of 3.5s is in good condition after being rolled and vibrated 6 times, and the relative compaction can reach over 98%. Therefore, from the perspective of the VC performance of the FGR mixture, a VC value of 3.5s is appropriate. Explanation of the above test phenomena can be carried out from the perspective of fluid mechanics theory. The VC process of FGR mixture is as follows: the action of vibration waves causes the aggregates and slurry of the concrete mixture to vibrate, and under influence of vibration waves, the viscosity coefficient of the cementitious material slurry decreases; the thickness of the critical slurry layer around the aggregate particles thins, resulting in an increase in free slurry, thus leading to a decrease in the yield stress and plastic viscosity coefficient. The aggregates were rearranged during the vibration process, and the slurry filled the gaps between the aggregates, gradually expelling internal air. At low vibratory compaction of the mixture and high layer thickness, the viscosity coefficient of the slurry after vibratory rolling decreases significantly and the free slurry increases significantly. This will cause the surface mixture to be over rolled while the bottom mixture cannot continue to increase in compaction (Wang et al. 2023 ). Table 4 Results of apparent density and relative compaction for FGR Layer no. Thickness /m Excitation force /kN Gradation VC value /s Apparent density /kg.m 3 Relative compaction /% 4 times 6 times 8 times 10 times 12 times 4 times 6 times 8 times 10 times 12 times First layer 0.5 280 three 3.5 2356 2424 2424 2429 - 95.3 98.1 98.1 98.3 - four 2.6 - 2304 2306 2323 2338 - 92.1 92.2 92.9 93.5 Second layer 0.4 280 three 3.5 2382 2426 2441 2443 2449 96.4 98.2 98.8 98.8 99.1 four 3.5 2371 2396 2450 2453 2464 94.8 95.8 98.0 98.1 98.5 Third layer 0.5 395 three 3.5 2444 2471 2471 2471 - 98.9 100.0 100.0 100.0 - four 3.5 2394 2468 2479 2487 2502 95.7 98.7 99.1 99.4 100.0 Fourth layer 0.5 395 three 3.5 2440 - - - - 97.5 - - - - four 3.5 2403 2408 - - 2481 96.1 96.3 - - 99.2 Fifth layer 0.4 395 four 3.5 2452 2481 2487 2501 - 98.0 99.2 99.4 100.0 - 4. Construction process parameters 4.1 Relationship between vibration roller operating parameters and relative compaction FGR process test block roller compacted concrete without vibration for 2 times, followed by VC for 4 ~ 12 times, and then VC for 2 times. The apparent density and relative compaction test outcomes of each layer of rolled concrete are listed in Table 4 . The number of rolling times for each strip in the table specifically refers to the number of vibration rolling times. The result of weak VC: for a layer thickness of 0.5m, the relative compaction of TGR can be 98% after two rounds without vibration rolling and six rounds of vibration rolling, while the relative compaction of FGR can only be 92.1%~93.5% after two rounds without vibration rolling and 6 ~ 12 rounds of vibration rolling. For a layer thickness of 0.4m, the relative compaction of the FGR can reach 98.0% after two rounds of vibration-free rolling and eight rounds of vibration rolling. The result of strong VC: for a layer thickness of 0.5m, the relative compaction of the TGR reaches 98% after two rounds of vibration-free rolling and four rounds of vibration rolling. When there are 6 ~ 10 rounds of vibration rolling, the relative compaction can all reach 100%; After two rounds of vibration-free rolling and six rounds of vibration rolling, the relative compaction of FGR can be 98.7%. For a layer thickness of 0.4m, the relative compaction of FGR can reach 98.0% after two rounds of vibration-free rolling and four rounds of vibration rolling. From a rheological perspective, compared with TGR mixture, the proportion of aggregates in the FGR mixture increases, which increases the biting force of the mixture, as a result, the proportion of the corresponding slurry is smaller, and there is less slurry in the free state, resulting in a higher yield stress; the plastic viscosity coefficient of the slurry simultaneously decreases. Therefore, the mixture is difficult to solidify. To ensure the same relative compaction, it is necessary to provide a larger output energy of the vibrating wheel. 4.2 Relationship of relative compaction and rolling times The relationship curve between the number of compaction and the relative compaction of three and four graded roller compacted concrete in each compaction layer is depicted in Fig. 5. From Fig. 5, the following two patterns can be obtained: ① When the number of VC times is 4–6, the relative compaction of TGR with different layer thicknesses and vibration forces increases rapidly; after the number of VC times reaches 6, the increase in relative compaction slows down as the number of VC times increases. The number of vibration rolling times increases the relative compaction of FGR with different layer thicknesses and vibration forces. weak vibration strong vibration Figure 5 Relationship of relative compaction and rolling times. 4.3 The relationship between relative compaction and compacted layer thickness The relative compaction of the FGR layers dramatically drops as the thickness of the roller-compacted layer increases when the vibration roller operates with a weak vibration; When the vibration roller uses a strong vibration for operation, the relative compaction of the FGR decreases slightly with the increase of the thickness of the roller compacted layer. The compaction process of roller compacted concrete is the process in which a vibrating roller propagates constant frequency and oscillation waves from top to bottom to the concrete mixture through a vibrating wheel. Due to the different proportions of various constituent materials and the workability in the mixture, the speed of propagation and degrees of attenuation along depth also vary. The thicker the layer of the mixture, the less vibratory energy is available to the mixture in the lower part of the layer. The longer the vibration time required to make the mixture uniform and dense, the more times it will be vibrated and rolled. If the layer is too thick, even if the compaction time is increased, the lower mixture cannot achieve the required density. Therefore, a reasonable layer thickness can achieve the goal of efficient construction and uniform and dense concrete quality. 4.4 Suggestions for construction process parameters of FGR Based on comprehensive results of the above experiments, while taking into account a certain relative compaction affluence, the recommended construction process parameters for FGR with layer thicknesses of 0.4m and 0.5m using the machinery, concrete raw materials, and mix proportions used in this experiment are taken down in Table 5 . Table 5 Suggestions for construction process parameters of FGR Thickness /m excitation force /kN VC value /s Rolling times Walking speed /km/h Relative compaction /% 0.4 395 3 ~ 5 No vibration twice + Vibration 6 times + No vibration twice 1.0 ~ 1.5 > 98.0 0.5 395 3 ~ 5 No vibration twice + Vibration 8 times + No vibration twice 1.0 ~ 1.5 > 98.0 5. Conclusions Different vibration roller construction process parameters were used to conduct compaction tests on FGR concrete specimens with different mix proportions. The test results were analyzed to propose recommended mix proportions and construction process parameters for FGR concrete. The analysis leads to the following conclusions: The water consumption of FGR is controlled at 71kg/m³~70kg/m³. Within the range of 4s ~ 6s of VC value, the VC value and air content are both optimal, which can save cementitious materials and effectively reduce the viscosity of FGR, which is beneficial for improving overall working performance and construction efficiency. In FGR, as the sand rate increases, the VC value and air content both increase slightly. From the outside of the mixture, it is more appropriate to choose a sand rate of 30%~32%. When the natural coarse aggregate combination ratio (extra large: large: medium: small) is 25:30:25:20, the VC value of the specimen is relatively large. In order to meet the requirements of the "Technical specification for hydraulic roller compacted concrete process test" (DL/T 5804 − 2019, 2019), it is necessary to ensure that the performance of FGR is not inferior to that of TGR, The combination ratio of natural coarse aggregates (extra large: large: medium: small) is suitable at 25:30:25:20. The VC value of 3.5s for the FGR mixture is suitable. After 6 rounds of strong vibration and vibration rolling, the surface bleeding is good. The relative compaction can reach over 98%. Under the conditions of the machinery, raw materials, and mix proportions used in the experiment, VC should be carried out with an excitation force of 395kN, a walking speed of 1.0 ~ 1.5km/h, and a layer thickness of 0.4m. FGR should be rolled twice without vibration, six times with vibration, and two times without vibration. FGR with a layer thickness of 0.5m should be rolled twice without vibration, eight times with vibration, and two times without vibration, relative compaction can be as high as 98% or more for all FGR. Declarations Conflicts of Interest The authors declare that they have no conflicts of interest to report regarding the present study. Author Contribution Yan Liang: Investigation, Formal analysis, Writing–original draft. Yan Shi: Conceptualization, Funding acquisition, Supervision, Investigation, Formal analysis, Writing–original draft. Cai Wu and Junzhou Huang: Supervision, Investigation. Tianlei Wang and Sheng Peng: Supervision. Acknowledgement This research is funded by ‘National Natural Science Foundation of China (CN)’-‘China’ (52179122, U2040222), ‘Natural Science Foundation of Hubei Province (CN)’-‘China’ (Grant No. 2022CFB662, 2022CFD026), ‘Tianjin Key Laboratory of Building Green Functional Materials of China (CN)’ - ‘China’ (Grant No. JZ-2023003), ‘Key Laboratory of Impact and Safety Engineering (Ningbo University), Ministry of Education of China (CN)’ - ‘China’ (Grant No. CJ202306) and their support is gratefully acknowledged. References Jia JS, Chen GX, Ma FL, Li XY (2006) Development level and engineering examples of roller compacted concrete dams. China Water & Power, Beijing Luo DN, Lu SH, Hu C, Xue ZX (2022) Experimental and numerical investigation on interlayer fracture process of roller compacted concrete. 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Rock Mech Rock Eng 55(6):3687–3702 https://doi.org/10.1007/s00603-022-02811-0 Amer N, Storey C, Delatte N (2004) Roller-compacted concrete mix design procedure with gyratory compactor. Transp Res Rec 1893(1):46–52. https://doi.org/10.3141/1893-06 Williams SG (2013) Comparison of the superpave gyratory and proctor compaction methods for the design of roller-compacted concrete pavements. Transp Res Rec 2342(1):106–112. https://doi.org/10.3141/2342-13 Amer N, Delatte N, Storey C (2003) Using Gyratory Compaction to Investigate Density and Mechanical Properties of Roller-Compacted Concrete. Transp Res Record J Transp Res Board 1834(1):77–84. https://doi.org/10.3141/1834-10 Selvam M, Kalyan NSSP, Kandasami RK, Singh S (2023) Assessing the effect of different compaction mechanisms on the internal structure of roller compacted concrete. Constr Build Mater 365:130072 https://doi.org/10.1016/j.conbuildmat.2022.130072 Şengün E, Alam B, Shabani R et al (2019) The effects of compaction methods and mix parameters on the properties of roller compacted concrete mixtures. Constr Build Mater 228:116807 https://doi.org/10.1016/j.conbuildmat.2019.116807 Şengün E, Shabani R, Alam B et al (2018) Comparison of Several Laboratory Compaction Practices Applied on Roller Compacted Concrete Pavements. In paper presentation, 13th International Congress on Advances in Civil Engineering, Turkey Zhao YL, Xie SY, Gao Y et al (2021) Prediction of the number of roller passes and degree of compaction of asphalt layer based on compaction energy. Constr Build Mater 277:122274 https://doi.org/10.1016/j.conbuildmat.2021.122274 Sengun E, Alam B, Shabani R, Yaman IO (2021) Strength and fracture properties of roller compacted concrete (RCC) prepared by an in-situ compaction procedure. Constr Build Mater 271:121563 https://doi.org/10.1016/j.conbuildmat.2020.121563 Golewski GL, Sadowski T (2016) A study of mode III fracture toughness in young and mature concrete with fly ash additive. Solid State Phenomena 254:120–125. https://doi.org /10.4028/www.scientific.net/SSP.254.120 Lindquist W, Darwin D, Browning J et al (2015) Implementation of concrete aggregate optimization. Constr Build Mater 74:49–56. https://doi.org/10.1016/j.conbuildmat.2014.10.027 Selvam M, Singh S (2022) Material selection and mixture proportioning methods for sustainable roller-compacted concrete pavements. J Mater Civ Eng 34(11):03122002 https:/ /doi.org/10.1061/(ASCE)MT.1943-5533.0004325 The Shatuo project training command post of the first armed police hydroelectric corps (2016) Construction technology of Shatuo hydropower station dam. China Water & Power, Beijing National Energy Administration (2019) Technical specification for hydraulic roller compacted concrete process test. China electric power, Beijing Lin YQ, Shi Y, Guo DM et al (2011) Study on site construction technology of four-graded RCC. Adv Mater Res 250–253:2927–2930. https://doi.org/10.4028/www.scientific.net/AMR.250-253.2927 Wang GH, Liu AB, Lu WB et al (2023) Failure modes and dynamic responses of roller compacted concrete gravity dams subjected to underwater contact explosion based on the cohesive model. Eng Fail Anal 150:107367. https://doi.org/10.1016/j.engfailanal.2023.107367 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. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. 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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-4290682","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":293504572,"identity":"e54e5a66-01af-43ce-9c21-e2bea4b4eb5d","order_by":0,"name":"Yan Shi","email":"","orcid":"","institution":"Changjiang River Scientific Research Institute, Changjiang Water Resources Commission","correspondingAuthor":false,"prefix":"","firstName":"Yan","middleName":"","lastName":"Shi","suffix":""},{"id":293504573,"identity":"497ee52b-159e-44ea-8fd3-eea9cef25479","order_by":1,"name":"Shihua Zhou","email":"","orcid":"","institution":"Changjiang River Scientific Research Institute, Changjiang Water Resources Commission","correspondingAuthor":false,"prefix":"","firstName":"Shihua","middleName":"","lastName":"Zhou","suffix":""},{"id":293504574,"identity":"08584d29-3d77-40a7-b049-5c470945c7b1","order_by":2,"name":"Cai Wu","email":"","orcid":"","institution":"Hubei Engineering University","correspondingAuthor":false,"prefix":"","firstName":"Cai","middleName":"","lastName":"Wu","suffix":""},{"id":293504576,"identity":"cc8c840b-833b-456d-b29c-33eb56936f8b","order_by":3,"name":"Junzhou Huang","email":"","orcid":"","institution":"Hubei Engineering University","correspondingAuthor":false,"prefix":"","firstName":"Junzhou","middleName":"","lastName":"Huang","suffix":""},{"id":293504578,"identity":"c8e63fab-8a94-4926-9f85-561c6553587e","order_by":4,"name":"Yan Liang","email":"","orcid":"","institution":"Wuhan University of Science and 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03:59:21","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-4290682/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-4290682/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":55257362,"identity":"cfbabe2f-6cf7-43d5-8dc1-e28ed97e4143","added_by":"auto","created_at":"2024-04-24 20:22:33","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":11372,"visible":true,"origin":"","legend":"\u003cp\u003eLayout of on-site construction process tests for TGR and FGR.\u003c/p\u003e","description":"","filename":"Onlinefloatimage1.png","url":"https://assets-eu.researchsquare.com/files/rs-4290682/v1/9ad93f9011f4a19c19dac25a.png"},{"id":55257361,"identity":"81e74c04-7e72-4f6e-aae5-b6ea35e82b98","added_by":"auto","created_at":"2024-04-24 20:22:33","extension":"jpeg","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":187133,"visible":true,"origin":"","legend":"\u003cp\u003e(a) VC value (s) (b) Gas content (%)\u003c/p\u003e\n\u003cp\u003eDiagram of water consumption (%) for FGR\u003c/p\u003e","description":"","filename":"floatimage2.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-4290682/v1/9ec721f0ebad25795eebc576.jpeg"},{"id":55257364,"identity":"51cc804d-9be7-470d-9c9e-19d774a35d50","added_by":"auto","created_at":"2024-04-24 20:22:33","extension":"jpeg","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":180325,"visible":true,"origin":"","legend":"\u003cp\u003e(a) VC value (s) (b) Gas content (%)\u003c/p\u003e\n\u003cp\u003eDiagram of sand rate (%) for FGR\u003c/p\u003e","description":"","filename":"floatimage3.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-4290682/v1/b8b11948568b9c976bb08727.jpeg"},{"id":55257365,"identity":"b5c03f5e-4f94-4c0e-8420-2f54f9a6c573","added_by":"auto","created_at":"2024-04-24 20:22:33","extension":"jpeg","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":242099,"visible":true,"origin":"","legend":"\u003cp\u003e(a) VC value (s) \u0026nbsp;(b) Gas content (%)\u003c/p\u003e\n\u003cp\u003eDiagram of Combination ratio of natural coarse aggregates for FGR\u003c/p\u003e","description":"","filename":"floatimage4.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-4290682/v1/28c46cae842f4f45a796a40e.jpeg"},{"id":55257363,"identity":"a5cf33bd-75b2-48c1-953e-3554adc1bc83","added_by":"auto","created_at":"2024-04-24 20:22:33","extension":"jpeg","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":66771,"visible":true,"origin":"","legend":"\u003cp\u003eweak vibration \u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;strong vibration\u003c/p\u003e\n\u003cp\u003eRelationship of relative compaction and rolling times.\u003c/p\u003e","description":"","filename":"floatimage5.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-4290682/v1/d7a5cecaa2729624318f2c40.jpeg"},{"id":57472305,"identity":"00b2d2f2-01ed-4aba-b528-b7bd45a7f5be","added_by":"auto","created_at":"2024-05-31 07:00:48","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1667911,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-4290682/v1/4d4403ba-beb9-4511-895b-cab427938694.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Research on the mix proportion and on-site construction technology of a four-graded roller compacted concrete","fulltext":[{"header":"1. Introduction","content":"\u003cp\u003eSince the 1970s, roller compacted concrete had appeared in experimental research in the field of dam construction, which adopted a method that combines the structural characteristics of normal concrete dams with the construction technology of earth-rock dams (Jia et al. \u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e2006\u003c/span\u003e). Roller compacted concrete has the advantages of low hydration heat, zero slump, and low cost, making it suitable for constructing large dam structures (Luo et al. \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2022\u003c/span\u003e). Roller compacted concrete dams combine the structural advantages of traditional concrete dams with the construction technology of earth-rockfill dams, resulting in lower construction costs, higher equipment utilization efficiency, and easier and faster construction compared to traditional concrete dams (Selvam et al. \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e2022\u003c/span\u003e). During the construction of roller compacted concrete dams, the combined action of strong mechanical vibration and rolling compaction was used to compact ultra dry and hard concrete. Due to the layered compaction during construction, there are often many horizontal construction joints in the roller compacted concrete dam, forming numerous horizontal layers (Shen et al. 2001). In experimental research and construction practice (Pacelli et al. \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e1993\u003c/span\u003e; Shen et al. \u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e2023\u003c/span\u003e; Liu et al. \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e2018\u003c/span\u003e), it was found that the quality of interlayer bonding had a significant impact on the performance of the roller compacted concrete dam.\u003c/p\u003e \u003cp\u003eDifferent material ratios, different material parameters, and unsuitable rolling construction techniques can cause local defects in the layer, which affects the stability of layer stress and the performance of the dam body. The adhesiveness of roller compacted concrete mixtures was very poor, and it was easy to cause aggregate separation during transportation and paving. After rolling, it may also result in non compaction, which affects the overall impermeability of the dam (Huang et al. \u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e2017\u003c/span\u003e). To reduce or avoid the phenomenon of coarse aggregate separation, in some projects, the maximum particle size and proportion of coarse aggregate are limited, and second-graded or third-graded roller compacted concrete was selected (Jia et al. \u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e2006\u003c/span\u003e). Increasing the maximum particle size of coarse aggregate can lessen the porosity of coarse aggregate and require less cementitious material overall. Therefore, how to find the balance point between the two requires extremely detailed experimental determination. Increasing the maximum particle size of coarse aggregate can reduce the porosity of coarse aggregate and reduce the amount of cementitious material used. The maximum particle size of crushed stone is usually limited to below 80mm (Huang et al. \u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e2017\u003c/span\u003e). Appropriate aggregate gradation and the ratio of coarse and fine aggregates are key factors in obtaining high-performance roller compacted concrete. The correct selection of aggregates will minimize voids, reduce segregation, and affect water demand. Therefore, determining the maximum size of aggregates and the ratio of coarse and fine aggregates is crucial. Hashemi et al. (\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e2018\u003c/span\u003e) investigated the impact of coarse to fine (C/F) aggregate ratio on the performance of two types of roller compacted concretes with cement contents of 9% and 12%, and mechanical performance tests were conducted to determine the hardening performance of roller compacted concrete. The experimental results indicated that increasing the C/F ratio from 0.6 to 1.8 tripled the Vebe time, while increasing the C/F ratio from 0.6 to 1.2 obviously reduced the porosity, and with the increase of the C/F ratio or cement content, the compressive, splitting tensile and bending tensile strengths of the specimens remarkably increased; Li et al. (\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e2015\u003c/span\u003e) analyzed the stress and seepage fields of a roller compacted concrete dam with three-graded roller compacted concrete and two-graded roller compacted concrete, and found that the impermeable layer constructed with three-graded roller compacted concrete has comparatively poor permeability resistance, while two-graded roller compacted concrete can improve its permeability resistance but may form seepage channels; Wu et al. (\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e2013\u003c/span\u003e) tested the combined compressive properties of concrete specimens with different sizes from 150 mm to 600 mm and found that the compressive strength decreased with the increase of cube size; Mohammed et al. (2020) completely redesigned the concrete mixture based on the maximum size of coarse aggregate and selected different types of mixtures for experimental comparison to research the impact of maximum aggregate size on the strength of normal and high-strength concrete and it was spotted that the compressive strength increased with the increase in the maximum size of coarse aggregate; based on the results obtained from experimental studies, Saouma et al. (\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e1991\u003c/span\u003e) and Li et al. (\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e2004\u003c/span\u003e) spotted that the tensile strength of dam concrete decreases with increasing aggregate size; Rao et al. (\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e2016\u003c/span\u003e) conducted a study to investigate the influence of aggregate particle size on the mechanical property of roller compacted concrete through the full-graded and wet sieve method test to comprehensively explore the impact of coarse aggregate\u0026rsquo;s grain size. The effect of coarse aggregate particle on the stability of roller compacted concrete in dams construction was also examined. The study provided technical support for the application of full gradation roller compacted concrete in practical engineering. It found that as the content of large-sized aggregates in full gradation concrete specimens increased, the air content of the concrete decreased, thereby improving the compressive strength, but larger maximum aggregate size resulted in poorer impermeability of concrete; Zhang et al. (\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e2020\u003c/span\u003e) mixed different contents of macadam into four graded roller compacted concrete with a maximum grain size of 120 mm. They carried out mechanical properties and freeze-thaw cycles tests, and based on the test data, established a quantitative relationship between the gravel content and various mechanical properties, as well as the degree of damage, and developed a freeze-thaw damage model; Yang et al. (\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e2016\u003c/span\u003e) found in the experiment that the reduction in the maximum particle size of macadam in fully graded concrete slightly reduces its compressive strength but slightly increases its tensile strength; Research into the microstructure of four graded roller compacted concrete (He et al. \u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e2018\u003c/span\u003e) has shown that larger-size aggregates lead to more free water being adsorbed, which can have an effect on cement hydration as well as porosity, and then has a major impact on mechanical properties of concrete.\u003c/p\u003e \u003cp\u003eThe compaction quality of roller compacted concrete is one of the key factors affecting its performance, and friction is generated in the aggregates during compaction, so the performance of roller compacted concrete has a close relationship with the aggregates used, and at the same time, it is also related to the relative compaction of vibration rolling of concrete, and the construction parameters and the number of times of rolling during compaction affect the relative compaction of concrete (Aghaeipour et al. 2020) \u003csup\u003e,\u003c/sup\u003e and controlling the compaction quality of layers is the key to ensuring the quality of the project.According to the development and research results of early roller compacted concrete(Hansen and Reinhardt \u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e2000\u003c/span\u003e), the crucial points impacting bonding strength of interlamination of roller compacted concrete are summarized, including the impact of the compaction effect of the upper layer of roller compacted concrete on the interlayer adhesive force: the upper layer of compacted concrete will reduce the concrete void ratio at the layer, forming a good bond, when the rolling is not compacted or the aggregate separation at the layer, it will make the concrete void ratio at the level increase significantly, leading to a reduction in the bonding strength of interlamination. When compaction is not compacted or aggregate separation occurs at the layer, the void ratio of concrete at the layer will increase significantly, leading to a reduction in interlayer adhesive force. Insufficient or excessive compaction will lead to deterioration of the concrete performance, which will have an impact on the integral stability or anti-seepage effect of the dam, and affect the healthy operation of the dam; the current research on rolling parameters includes the role of different rolling parameters in vibratory compacted (VC) (Kokubu et al. \u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e1996\u003c/span\u003e), the monitoring method of rolling parameters(Zhong et al. \u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e2009\u003c/span\u003e; Zhong et al. \u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e2011\u003c/span\u003e)and the compaction quality control technology based on rolling parameters (Liu et al. \u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e2012\u003c/span\u003e). Liu et al. (Liu et al. \u003cspan citationid=\"CR37\" class=\"CitationRef\"\u003e2015\u003c/span\u003e) used the unit compaction energy index to quantify the quality of roller compacted concrete dams; Godoi et al. (\u003cspan citationid=\"CR39\" class=\"CitationRef\"\u003e2019\u003c/span\u003e) improved the technique of using conventional X-ray imaging to detect the compaction degree of compacted layers. Compared with conventional concrete, roller compacted concrete requires more aggregates for compaction and consolidation. Both the degree of compaction and the number of rolling vibrations needed during construction are impacted (Harrington et al. \u003cspan citationid=\"CR40\" class=\"CitationRef\"\u003e2010\u003c/span\u003e; Delatte et al. 2006); Xu et al. (\u003cspan citationid=\"CR43\" class=\"CitationRef\"\u003e2022\u003c/span\u003e) analyzed the compaction mechanism and established a compaction quality control system based on the results of on-site experiments, obtained economic and efficient compaction quality parameters to meet the construction quality control and rapid mechanized construction, and verified their reliability; Amer et al. (\u003cspan citationid=\"CR45\" class=\"CitationRef\"\u003e2004\u003c/span\u003e) Compaction of roller compacted concrete mixtures to different densities using the rotary compactor and experimental study on the improvement of roller compacted concrete mix proportion using rotary compactor; Williams et al. (2013) and Amer et al. (\u003cspan citationid=\"CR47\" class=\"CitationRef\"\u003e2003\u003c/span\u003e) compared the compaction densities and mechanical properties of roller compacted concrete compacted using the Proctor compaction methods with those compacted using gyratory compaction method, and found that the gyratory compaction method produced significantly higher densities at higher water contents; Selvam et al. (\u003cspan citationid=\"CR48\" class=\"CitationRef\"\u003e2023\u003c/span\u003e) in a comprehensive investigation found that the main factors affecting aggregate distribution are the ratio of aggregates to mortar, particle spacing, and compaction method. The compaction method plays a crucial role in the formation of the internal structure of roller compacted concrete. After conducting compaction tests on the samples using multiple compaction methods, it was found that the maximum density and compressive strength in the samples were compacted using the vibrating hammer; Şeng\u0026uuml;n et al. (\u003cspan citationid=\"CR52\" class=\"CitationRef\"\u003e2018\u003c/span\u003e; \u003cspan citationid=\"CR50\" class=\"CitationRef\"\u003e2019\u003c/span\u003e) used four laboratory compaction methods for the compaction of roller compacted concrete of two mix proportions and found that as the VeBe time increased, the difference in compaction coefficients obtained from specimens compacted using different compaction methods increased. Using a vibrating hammer for compaction can make specimens with low cement content have higher density and strength values. The strength and density of samples compacted using a rotary compactor are more similar to the actual engineering situation; Zhao et al. (\u003cspan citationid=\"CR53\" class=\"CitationRef\"\u003e2021\u003c/span\u003e) modeled the change of compaction energy density with compaction degree, quantified the compaction energy density and proposed a new method for compaction program development and adjustment of the number of rolling times. Fracture toughness (K\u003csub\u003eIC\u003c/sub\u003e and CTOD\u003csub\u003eC\u003c/sub\u003e) is an important parameter in determining the performance of ultra-high arch dams; Sengun et al. (\u003cspan citationid=\"CR55\" class=\"CitationRef\"\u003e2021\u003c/span\u003e) designed seven different mixtures to study the fracture characteristics of roller compacted concrete in their experiment. The experimental results showed that as the maximum aggregate particle size and compaction coefficient of aggregates increased, the fracture parameters also increased.\u003c/p\u003e \u003cp\u003eWith the development of dam building technology in recent years, four-graded roller compacted concrete has gradually been considered and applied in actual projects, its research and use have imcreased the maximum particle size of aggregate, saved water consumption, further reduced the amount of mortar and cementitious materials of roller compacted concrete (Golewski and Sadowski, \u003cspan citationid=\"CR57\" class=\"CitationRef\"\u003e2016\u003c/span\u003e), improved the crack resistance performance, and fully utilized its technical and economic advantages (Lindquist et al. 2014). However, due to the increase in aggregate particle size, it may cause problems such as aggregate separation or internal defects in concrete, and may also affect the compaction effect of vibratory milling and thus affect the structural impermeability of the dam and the performance of the mix (Hashemi et al. \u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e2018\u003c/span\u003e). Roller compacted concrete requires proper compaction methods to achieve the required engineering properties, improved compaction increases the load carrying capacity and thus the service life of the project (Selvam et al. \u003cspan citationid=\"CR48\" class=\"CitationRef\"\u003e2023\u003c/span\u003e). The dense accumulation of aggregates in roller compacted concrete mixture helps to achieve higher compressive strengths (Selvam et al. \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e2022\u003c/span\u003e). The use of a four-graded roller compacted concrete instead of a three-stage roller compacted concrete leads to a reduction in the dosage of cementitious materials, and a reduction in the hydration temperature rise is reduced, which can effectively simplify the temperature control measures, increase the paving layer thickness in construction, reduce the level, improve the construction speed and productivity, and give full play to the technical and economic advantages of continuous pouring and rapid rise of the roller compacted concrete (2016). However, there are not many researches on the four-graded distribution of roller compacted concrete, and many aspects of the technical information have certain limitations or are almost blank. The water-cement ratio and aggregate proportion, as well as the choice of construction technology, all affect the performance of the roller compacted concrete. This paper analyzes the above problems experimentally to provide a reference for the choice of water consumption, sand rate, coarse aggregate proportion and construction technology of four-graded roller compacted concrete.\u003c/p\u003e"},{"header":"2. Analysis of mix proportion of four-graded roller compacted concrete","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003e2.1 Cement\u003c/h2\u003e \u003cp\u003eThe cement is 42.5 ordinary Portland cement, which is produced by Chongqing Maotian. The physical and mechanical properties of cement are shown in Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e.\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\u003ePhysical and mechanical properties of cement\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"13\"\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 \u003cdiv align=\"left\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c8\" colnum=\"8\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c9\" colnum=\"9\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c10\" colnum=\"10\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c11\" colnum=\"11\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c12\" colnum=\"12\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c13\" colnum=\"13\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eFineness\u003c/p\u003e \u003cp\u003e(%)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eApparent density\u003c/p\u003e \u003cp\u003e(m\u003csup\u003e2\u003c/sup\u003e/kg)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eDensity (kg/m\u003csup\u003e3\u003c/sup\u003e)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eConsistence\u003c/p\u003e \u003cp\u003e(%)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eStability\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c7\" namest=\"c6\"\u003e \u003cp\u003eSetting time\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"3\" nameend=\"c10\" namest=\"c8\"\u003e \u003cp\u003eCompressive strength\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"3\" nameend=\"c13\" namest=\"c11\"\u003e \u003cp\u003eBending strength\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003eInitial setting\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c7\"\u003e \u003cp\u003eFinal setting\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c8\"\u003e \u003cp\u003e3d\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c9\"\u003e \u003cp\u003e7d\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c10\"\u003e \u003cp\u003e28d\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c11\"\u003e \u003cp\u003e3d\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c12\"\u003e \u003cp\u003e7d\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c13\"\u003e \u003cp\u003e28d\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e2.0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e405\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e3100\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e25.8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003equalified\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e1:30\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e2:33\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e \u003cp\u003e32.4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c9\"\u003e \u003cp\u003e42.4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c10\"\u003e \u003cp\u003e53.6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c11\"\u003e \u003cp\u003e5.6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c12\"\u003e \u003cp\u003e6.8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c13\"\u003e \u003cp\u003e7.7\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 Fly ash\u003c/h2\u003e \u003cp\u003eFly ash is produced by Guizhou Dalong Power Plant, with a specific surface area of 352m\u003csup\u003e2\u003c/sup\u003e/kg and a water demand ratio of 95%. It has been tested to meet the standard of Class II fly ash in \u003cem\u003eGB 1596-91\u003c/em\u003e.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec5\" class=\"Section2\"\u003e \u003ch2\u003e2.3 Admixture\u003c/h2\u003e \u003cp\u003eHLC-NAF retarder and high-efficiency water reducing agent, produced by Nanjing Ruidi High-tech Company; the air entraining agent is produced by Shanxi Sangmusi Building Materials Chemical Co., Ltd.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec6\" class=\"Section2\"\u003e \u003ch2\u003e2.4 Aggregate materials\u003c/h2\u003e \u003cp\u003eThe fineness modulus of the artificial sand is F.M\u0026thinsp;=\u0026thinsp;2.72 and the stone dust content is 14.2%.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec7\" class=\"Section2\"\u003e \u003ch2\u003e2.5 Specimen design and preparation\u003c/h2\u003e \u003cp\u003eAccording to the \"Technical specification for hydraulic roller compacted concrete process test\" (DL/T 5804\u0026thinsp;\u0026minus;\u0026thinsp;2019, 2019), the water cement ratio (w/c) is taken as 0.50, the water consumption is set to 70kg/m\u0026sup3;, 71kg/m\u0026sup3;, 72kg/m\u0026sup3;, 73kg/m\u0026sup3;, 74kg/m\u0026sup3;, and 78kg/m\u0026sup3;, the fly ash content is taken as 55% and 60%, and the sand rate is set to 28%, 30%, 32%, and 34%. The admixtures for roller compacted concrete include water reducing agents and air entraining agents, with a water reducing agent value of 0.7% and an air entraining agent value of 0.05 and 0.06. The compacted density of the stone is 1860kg/m\u0026sup3;, and the combination ratio values are 0:30:40:30 and 20:30:30:30:20. TGR and FGR represent third-graded and fourth-graded roller compacted concrete, respectively, with the following numbers indicating the sample number.\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\u003eSpecimens design details\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"12\"\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 \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 \u003cdiv align=\"left\" class=\"colspec\" colname=\"c8\" colnum=\"8\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c9\" colnum=\"9\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c10\" colnum=\"10\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c11\" colnum=\"11\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c12\" colnum=\"12\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eSpecimen\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003ew/c\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003ewater consumption\u003c/p\u003e \u003cp\u003e(kg/m\u003csup\u003e3\u003c/sup\u003e)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eFly ash dosage\u003c/p\u003e \u003cp\u003e(%)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eSand rate\u003c/p\u003e \u003cp\u003e(%)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c7\" namest=\"c6\"\u003e \u003cp\u003eAdmixture\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c9\" namest=\"c8\"\u003e \u003cp\u003eNatural coarse aggregate\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"3\" nameend=\"c12\" namest=\"c10\"\u003e \u003cp\u003eFGR compacted concrete\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003eSuperplas-ticizer\u003c/p\u003e \u003cp\u003e(%)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c7\"\u003e \u003cp\u003eAir entrain admixture (%)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c8\"\u003e \u003cp\u003eCombination ratio\u003c/p\u003e \u003cp\u003e(Extra large: Large: Medium: Small)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c9\"\u003e \u003cp\u003eTap density\u003c/p\u003e \u003cp\u003e(kg/m\u003csup\u003e3\u003c/sup\u003e)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c10\"\u003e \u003cp\u003eVC value (s)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c11\"\u003e \u003cp\u003eGas content\u003c/p\u003e \u003cp\u003e(%)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c12\"\u003e \u003cp\u003eCompacted wet density\u003c/p\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\u003eTGR-0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e0.50\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e78\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e55\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e34\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e0.7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e0.06\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e0:30:40:30\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c9\"\u003e \u003cp\u003e1860\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c10\"\u003e \u003cp\u003e3.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c11\"\u003e \u003cp\u003e4.0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c12\"\u003e \u003cp\u003e2630\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eFGR-1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e0.50\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e70\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e60\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e30\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e0.7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e0.05\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e20:30:30:20\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c9\"\u003e \u003cp\u003e1860\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c10\"\u003e \u003cp\u003e5.9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c11\"\u003e \u003cp\u003e4.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c12\"\u003e \u003cp\u003e2438\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eFGR-2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e0.50\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e72\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e60\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e30\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e0.7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e0.05\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e20:30:30:20\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c9\"\u003e \u003cp\u003e1860\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c10\"\u003e \u003cp\u003e4.7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c11\"\u003e \u003cp\u003e3.9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c12\"\u003e \u003cp\u003e2438\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eFGR-3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e0.50\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e74\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e60\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e30\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e0.7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e0.05\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e20:30:30:20\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c9\"\u003e \u003cp\u003e1860\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c10\"\u003e \u003cp\u003e2.9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c11\"\u003e \u003cp\u003e2.4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c12\"\u003e \u003cp\u003e2438\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eFGR-4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e0.50\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e72\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e60\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e28\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e0.7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e0.05\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e20:30:30:20\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c9\"\u003e \u003cp\u003e1860\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c10\"\u003e \u003cp\u003e4.4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c11\"\u003e \u003cp\u003e3.7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c12\"\u003e \u003cp\u003e2438\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eFGR-5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e0.50\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e72\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e60\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e32\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e0.7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e0.05\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e20:30:30:20\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c9\"\u003e \u003cp\u003e1860\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c10\"\u003e \u003cp\u003e4.9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c11\"\u003e \u003cp\u003e4.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c12\"\u003e \u003cp\u003e2438\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eFGR-6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e0.50\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e71\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e60\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e30\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e0.7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e0.05\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e20:30:30:20\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c9\"\u003e \u003cp\u003e1860\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c10\"\u003e \u003cp\u003e3.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c11\"\u003e \u003cp\u003e3.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c12\"\u003e \u003cp\u003e2438\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eFGR-7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e0.50\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e73\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e60\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e32\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e0.7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e0.05\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e20:30:30:20\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c9\"\u003e \u003cp\u003e1860\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c10\"\u003e \u003cp\u003e2.6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c11\"\u003e \u003cp\u003e3.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c12\"\u003e \u003cp\u003e2438\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eFGR-8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e0.50\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e73\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e60\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e30\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e0.7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e0.06\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e20:30:30:20\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c9\"\u003e \u003cp\u003e1860\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c10\"\u003e \u003cp\u003e4.6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c11\"\u003e \u003cp\u003e3.7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c12\"\u003e \u003cp\u003e2438\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eFGR-9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e0.50\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e72\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e60\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e30\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e0.7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e0.05\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e25:30:25:20\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c9\"\u003e \u003cp\u003e1860\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c10\"\u003e \u003cp\u003e4.0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c11\"\u003e \u003cp\u003e4.0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c12\"\u003e \u003cp\u003e2438\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eFGR-10\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e0.50\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e71\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e60\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e30\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e0.7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e0.05\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e20:30:30:20\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c9\"\u003e \u003cp\u003e1860\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c10\"\u003e \u003cp\u003e5.3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c11\"\u003e \u003cp\u003e4.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c12\"\u003e \u003cp\u003e2438\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eFGR-11\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e0.50\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e72\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e60\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e30\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e0.7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e0.05\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e30:30:30:20\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c9\"\u003e \u003cp\u003e1860\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c10\"\u003e \u003cp\u003e3.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c11\"\u003e \u003cp\u003e4.3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c12\"\u003e \u003cp\u003e2438\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\u003e2.6 Experimental setup and program\u003c/h2\u003e \u003cp\u003eAccording to the proportioning design in 4 times to add materials, first add sand, stone, mix well and then add admixture, then 2/3 water and water reducing agent stir are added and stirred well, finally add 1/3 water. After weighing the raw materials, mix them well in the mixer. The production of the test specimen of roller compacted concrete was produced at the Shatuo Hydropower Station, using the method of insertion pounding and pouring, vibration compacting, by loading the materials in layers, inserting the pounding rod into the uniform insertion pounding after the completion of loading in each layer, and finally completing it by using the concrete roller to finish the compacting. The length of the test specimen is 30m, the width is 15m, and the thickness is 2.3m. According to the design scheme in Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e, the rolling area is divided into the comparative rolling area and the test rolling area, the comparative rolling area is TGR, and the test rolling area is the FGR. The on-site construction process test arrangement of roller compacted concrete is shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eThe longitudinal arrangement of the on-site construction process along the thickness direction of the test specimen includes 5 layers. From the bottom up, there are layers 1 to 5, with a total thickness of 2.3m. The thickness of the first layer is 0.4m, and a test combination of optimal VC value and optimal compaction frequency is adopted; The thickness of the second and third layers is both 0.5m, and the optimal VC value and different compaction times are used as experimental combinations; The thickness of the fourth layer is 0.4m, and a combination of 3\u0026thinsp;~\u0026thinsp;5s VC value and different compaction times is used for testing; The thickness of the fifth layer is 0.5m, and a combination of VC values of 1\u0026thinsp;~\u0026thinsp;3s and different rolling times is adopted.\u003c/p\u003e \u003cp\u003eThe concrete mixture that has passed the performance test at the outlet of the mixing plant shall be transported by a 20T dump truck to the test block for performance and compaction process testing of the mixture. The performance of concrete mixtures includes VC value, apparent density test, as well as evaluation of aggregate separation and wrapping; By conducting compaction process experiments, the relationship between VC value, compacted layer thickness, compaction frequency, relative compaction, and excitation force was obtained, and recommended construction process parameters for FGR were proposed.\u003c/p\u003e \u003c/div\u003e"},{"header":"3. Analysis of on-site construction parameters","content":"\u003cdiv id=\"Sec10\" class=\"Section2\"\u003e \u003ch2\u003e3.1 Water consumption (%)\u003c/h2\u003e \u003cp\u003eWhen other parameters are kept consistent, the water consumption has a significant impact on the VC value and air content of FGR. Therefore, specimens TGR-0, FGR-1, FGR-2, FGR-3, and FGR-10 were selected for research, and the water consumption diagram shown in Fig.\u0026nbsp;2 was drawn. From Fig.\u0026nbsp;2a, it can be seen that when the water consumption is 74kg/m\u0026sup3;, the VC value of specimen FGR-3 is the smallest, indicating excess water; When the VC value is set to 4s\u0026thinsp;~\u0026thinsp;6s, the water consumption is 72kg/m\u0026sup3;~70kg/m\u0026sup3;. Compared with the TGR-0 specimen, the water consumption can be reduced by 8kg/m\u0026sup3;~10kg/m\u0026sup3;, saving 16kg/m\u0026sup3;~20kg/m\u0026sup3; of cementitious material. From Fig.\u0026nbsp;2b, it can be seen that compared with specimen TGR-0, specimen FGR-1 and specimen FGR-10 have higher air content, which can effectively reduce the viscosity of FGR, which is beneficial for improving overall working performance and construction efficiency. In summary, it can be seen that when the water consumption is not higher than 73kg/m\u0026sup3;, the VC value of FGR will be better than that of TGR; When the water consumption is not higher than 71kg/m\u0026sup3;, the air content of FGR will be better than that of TGR. Therefore, it is recommended to control the water consumption of FGR within the range of 71kg/m\u0026sup3; to 70kg/m\u0026sup3;, where the VC value and air content are optimal.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e(a) VC value (s) (b) Gas content (%)\u003c/p\u003e \u003cp\u003e \u003cb\u003eFigure\u0026nbsp;2\u003c/b\u003e Diagram of water consumption (%) for FGR\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec11\" class=\"Section2\"\u003e \u003ch2\u003e3.2 Sand rate (%)\u003c/h2\u003e \u003cp\u003eFigure\u0026nbsp;3 shows the influence mechanism of sand rate on the VC value and air content of FGR. When the sand rate is different, the VC values of specimen TGR-0 are all lower than those of specimen FGR-2, specimen FGR-4, and specimen FGR-5, indicating that the sand rate proposed in this paper can be used for FGR. In FGR, as the sand rate increases, the VC value and air content both increase slightly. Within the range of sand rate of 28\u0026ndash;32%, the influence of sand rate on the VC value and air content of FGR is not significant. In Fig.\u0026nbsp;3(b), the gas content of specimen TGR-0 is only lower than that of specimen FGR-4. In addition, there is no phenomenon of increasing the VC value at a sand content of 28%. This is because roller compacted concrete contains more sand than normal concrete does. In addition, the VC value test is different from the slump test. From the appearance of the mixture, it is more appropriate to choose a sand rate of 30\u0026ndash;32% for FGR, which is consistent with the commonly used sand rate of 34% for TGR.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e(a) VC value (s) (b) Gas content (%)\u003c/p\u003e \u003cp\u003e \u003cb\u003eFigure\u0026nbsp;3\u003c/b\u003e Diagram of sand rate (%) for FGR\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec12\" class=\"Section2\"\u003e \u003ch2\u003e3.3 Combination ratio of natural coarse aggregates (Extra large: Large: Medium: Small)\u003c/h2\u003e \u003cp\u003eThe \"Technical specification for hydraulic roller compacted concrete process test\" (DL/T 5804\u0026thinsp;\u0026minus;\u0026thinsp;2019, 2019) provides a combination ratio of natural coarse aggregates (extra large: extra large: extra medium: extra small) for TGR, which is 0:30:40:30. The mass percentage of extra large natural coarse aggregates is 0, indicating that extra large natural coarse aggregates are not necessary in the performance analysis of TGR. The combination ratio of natural coarse aggregates for FGR (extra large: large: medium: small) is 20:30:30:20, 25:30:25:20, and 30:30:30:20, respectively. The ratio of extra large natural coarse aggregates to medium natural coarse aggregates is 2/3, 1 and 1, respectively, indicating that the extra large and medium particle sizes of natural coarse aggregates have a noteworthy effect on the performance of FGR. The impact of three natural coarse aggregate combinations on the VC value and air content of FGR are studied in this article, aiming to reveal the relationship between the natural coarse aggregate combination ratio, VC value, and air content, and obtain a suitable natural coarse aggregate combination ratio (large: large: medium: small) for the widespread application of FGR.\u003c/p\u003e \u003cp\u003eAccording to Fig.\u0026nbsp;4, when the natural coarse aggregate combination ratio (extra large: large: medium: small) is 20:30:30:20 and 25:30:25:20, the VC values of specimens FGR-2 and FGR-9 are larger than those of specimens TGR-0, with an increase range of 14.29\u0026ndash;34.29%; When other parameters are the same, the gas content of specimens FGR-9 and FGR-11 is not less than that of specimen TGR-0, with a growth range of 0-7.5%. In order to meet the requirements of the \"Technical specification for hydraulic roller compacted concrete process test\" (DL/T 5804\u0026thinsp;\u0026minus;\u0026thinsp;2019, 2019) and ensure that the performance of FGR is not inferior to that of TGR, it is recommended to use a ratio of 25:30:25:20 for the combination of natural coarse aggregates (extra large: large: medium: small).\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e(a) VC value (s) (b) Gas content (%)\u003c/p\u003e \u003cp\u003e \u003cb\u003eFigure\u0026nbsp;4\u003c/b\u003e Diagram of Combination ratio of natural coarse aggregates for FGR\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec13\" class=\"Section2\"\u003e \u003ch2\u003e3.4 Aggregate coating and resistance to segregation\u003c/h2\u003e \u003cp\u003eIn order to determine the workability of the FGR mixture, a 20T dump truck was used to directly store the material and complete the unloading in one go. The measured accumulation of the mixture was recorded in Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e. As can be seen from Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e, both specimen FGR-6 and specimen FGR-7 had good coated large aggregates in the FGR mixes. The number of rolled aggregates in the mixing material pile of FGR is higher than that of TGR. The direct reason for the separation of aggregate particles in the concrete mixture during the unloading process is due to the displacement caused by different movements between the aggregates. When changing from motion to rest, the relative displacement of the aggregate to the surrounding mix is positively correlated to the square of the particle radius, the density and the initial relative velocity, and varies inversely with the viscosity coefficient of the mix (Lin et al. \u003cspan citationid=\"CR63\" class=\"CitationRef\"\u003e2011\u003c/span\u003e). Improving the separation resistance of FGR can be achieved in the following ways: a proper mixing proportion can be used to improve the cohesion of the concrete mixture, supplemented by other measures such as reducing the number of times the mixture is transported, reducing the height of unloading and material piles, using large pavers, and manually dispersing the large aggregates concentrated due to separation, which can effectively prevent or reduce the separation of aggregates in FGR, Improve the uniformity of roller compacted concrete mixtures and the quality.\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\u003eParameters of FGR roller compacted concrete mixture windrower\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=\"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=\"\u0026times;\" 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=\"left\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\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\u003eVC value (s)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eVolume\u003c/p\u003e \u003cp\u003e/m\u003csup\u003e3\u003c/sup\u003e\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003ePile height\u003c/p\u003e \u003cp\u003e/m\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eLand occupation of material piles\u003c/p\u003e \u003cp\u003e/m\u003csup\u003e2\u003c/sup\u003e\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003eNumber of large aggregate roll-offs\u003c/p\u003e \u003cp\u003e/piece\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c7\"\u003e \u003cp\u003eAggregate coating condition\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTGR-0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e3.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e1.33\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026times;\" colname=\"c5\"\u003e \u003cp\u003e4.0\u0026times;3.0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003egood\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eFGR-6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e3.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e1.23\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026times;\" colname=\"c5\"\u003e \u003cp\u003e5.0\u0026times;2.8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e22\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003eRelatively good\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eFGR-7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e2.6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e1.28\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026times;\" colname=\"c5\"\u003e \u003cp\u003e4.8\u0026times;2.9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e19\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003eRelatively good\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=\"Sec14\" class=\"Section2\"\u003e \u003ch2\u003e3.5 VC characteristics of mixtures\u003c/h2\u003e \u003cp\u003eThe process test of FGR adopts the YZ20C type fully hydraulic single steel wheel vibration roller produced by Sany Group. The weak vibration represents the excitation force of the vibrating roller as 280kN, while the strong vibration represents it as 395kN. Table\u0026nbsp;\u003cspan refid=\"Tab4\" class=\"InternalRef\"\u003e4\u003c/span\u003e contains the findings from the roller compacted concrete's apparent density and relative compaction tests. The experimental results show that the surface of the FGR mixture with a VC value of 2.6s is prone to bleeding after being compacted 6 times with a weak vibration. However, the relative compaction of the concrete at this point was only about 92%. The surface of the FGR mixture with a VC value of 3.5s is in good condition after being rolled and vibrated 6 times, and the relative compaction can reach over 98%. Therefore, from the perspective of the VC performance of the FGR mixture, a VC value of 3.5s is appropriate.\u003c/p\u003e \u003cp\u003eExplanation of the above test phenomena can be carried out from the perspective of fluid mechanics theory. The VC process of FGR mixture is as follows: the action of vibration waves causes the aggregates and slurry of the concrete mixture to vibrate, and under influence of vibration waves, the viscosity coefficient of the cementitious material slurry decreases; the thickness of the critical slurry layer around the aggregate particles thins, resulting in an increase in free slurry, thus leading to a decrease in the yield stress and plastic viscosity coefficient. The aggregates were rearranged during the vibration process, and the slurry filled the gaps between the aggregates, gradually expelling internal air. At low vibratory compaction of the mixture and high layer thickness, the viscosity coefficient of the slurry after vibratory rolling decreases significantly and the free slurry increases significantly. This will cause the surface mixture to be over rolled while the bottom mixture cannot continue to increase in compaction (Wang et al. \u003cspan citationid=\"CR64\" class=\"CitationRef\"\u003e2023\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\u003eResults of apparent density and relative compaction for FGR\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"15\"\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=\"left\" 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=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c8\" colnum=\"8\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c9\" colnum=\"9\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c10\" colnum=\"10\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c11\" colnum=\"11\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c12\" colnum=\"12\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c13\" colnum=\"13\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c14\" colnum=\"14\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c15\" colnum=\"15\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eLayer no.\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eThickness\u003c/p\u003e \u003cp\u003e/m\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eExcitation force\u003c/p\u003e \u003cp\u003e/kN\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eGradation\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eVC value /s\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"5\" nameend=\"c10\" namest=\"c6\"\u003e \u003cp\u003eApparent density /kg.m\u003csup\u003e3\u003c/sup\u003e\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"5\" nameend=\"c15\" namest=\"c11\"\u003e \u003cp\u003eRelative compaction /%\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003e4\u003c/p\u003e \u003cp\u003etimes\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c7\"\u003e \u003cp\u003e6\u003c/p\u003e \u003cp\u003etimes\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c8\"\u003e \u003cp\u003e8\u003c/p\u003e \u003cp\u003etimes\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c9\"\u003e \u003cp\u003e10\u003c/p\u003e \u003cp\u003etimes\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c10\"\u003e \u003cp\u003e12\u003c/p\u003e \u003cp\u003etimes\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c11\"\u003e \u003cp\u003e4\u003c/p\u003e \u003cp\u003etimes\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c12\"\u003e \u003cp\u003e6\u003c/p\u003e \u003cp\u003etimes\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c13\"\u003e \u003cp\u003e8\u003c/p\u003e \u003cp\u003etimes\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c14\"\u003e \u003cp\u003e10\u003c/p\u003e \u003cp\u003etimes\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c15\"\u003e \u003cp\u003e12\u003c/p\u003e \u003cp\u003etimes\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eFirst layer\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003e0.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003e280\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003ethree\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e3.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e2356\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e2424\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e2424\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e2429\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e \u003cp\u003e95.3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e \u003cp\u003e98.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c13\"\u003e \u003cp\u003e98.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c14\"\u003e \u003cp\u003e98.3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c15\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003efour\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e2.6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e2304\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e2306\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e2323\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e2338\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e \u003cp\u003e92.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c13\"\u003e \u003cp\u003e92.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c14\"\u003e \u003cp\u003e92.9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c15\"\u003e \u003cp\u003e93.5\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eSecond layer\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003e0.4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003e280\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003ethree\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e3.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e2382\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e2426\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e2441\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e2443\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e2449\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e \u003cp\u003e96.4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e \u003cp\u003e98.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c13\"\u003e \u003cp\u003e98.8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c14\"\u003e \u003cp\u003e98.8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c15\"\u003e \u003cp\u003e99.1\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003efour\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e3.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e2371\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e2396\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e2450\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e2453\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e2464\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e \u003cp\u003e94.8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e \u003cp\u003e95.8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c13\"\u003e \u003cp\u003e98.0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c14\"\u003e \u003cp\u003e98.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c15\"\u003e \u003cp\u003e98.5\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eThird layer\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003e0.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003e395\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003ethree\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e3.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e2444\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e2471\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e2471\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e2471\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e \u003cp\u003e98.9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e \u003cp\u003e100.0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c13\"\u003e \u003cp\u003e100.0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c14\"\u003e \u003cp\u003e100.0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c15\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003efour\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e3.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e2394\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e2468\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e2479\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e2487\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e2502\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e \u003cp\u003e95.7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e \u003cp\u003e98.7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c13\"\u003e \u003cp\u003e99.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c14\"\u003e \u003cp\u003e99.4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c15\"\u003e \u003cp\u003e100.0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eFourth layer\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003e0.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003e395\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003ethree\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e3.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e2440\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e \u003cp\u003e97.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c13\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c14\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c15\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003efour\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e3.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e2403\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e2408\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e2481\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e \u003cp\u003e96.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e \u003cp\u003e96.3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c13\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c14\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c15\"\u003e \u003cp\u003e99.2\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eFifth layer\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e0.4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e395\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003efour\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e3.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e2452\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e2481\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e2487\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e2501\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e \u003cp\u003e98.0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e \u003cp\u003e99.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c13\"\u003e \u003cp\u003e99.4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c14\"\u003e \u003cp\u003e100.0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c15\"\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"},{"header":"4. Construction process parameters","content":"\u003cdiv id=\"Sec16\" class=\"Section2\"\u003e \u003ch2\u003e4.1 Relationship between vibration roller operating parameters and relative compaction\u003c/h2\u003e \u003cp\u003eFGR process test block roller compacted concrete without vibration for 2 times, followed by VC for 4\u0026thinsp;~\u0026thinsp;12 times, and then VC for 2 times. The apparent density and relative compaction test outcomes of each layer of rolled concrete are listed in Table\u0026nbsp;\u003cspan refid=\"Tab4\" class=\"InternalRef\"\u003e4\u003c/span\u003e. The number of rolling times for each strip in the table specifically refers to the number of vibration rolling times.\u003c/p\u003e \u003cp\u003eThe result of weak VC: for a layer thickness of 0.5m, the relative compaction of TGR can be 98% after two rounds without vibration rolling and six rounds of vibration rolling, while the relative compaction of FGR can only be 92.1%~93.5% after two rounds without vibration rolling and 6\u0026thinsp;~\u0026thinsp;12 rounds of vibration rolling. For a layer thickness of 0.4m, the relative compaction of the FGR can reach 98.0% after two rounds of vibration-free rolling and eight rounds of vibration rolling.\u003c/p\u003e \u003cp\u003eThe result of strong VC: for a layer thickness of 0.5m, the relative compaction of the TGR reaches 98% after two rounds of vibration-free rolling and four rounds of vibration rolling. When there are 6\u0026thinsp;~\u0026thinsp;10 rounds of vibration rolling, the relative compaction can all reach 100%; After two rounds of vibration-free rolling and six rounds of vibration rolling, the relative compaction of FGR can be 98.7%. For a layer thickness of 0.4m, the relative compaction of FGR can reach 98.0% after two rounds of vibration-free rolling and four rounds of vibration rolling.\u003c/p\u003e \u003cp\u003eFrom a rheological perspective, compared with TGR mixture, the proportion of aggregates in the FGR mixture increases, which increases the biting force of the mixture, as a result, the proportion of the corresponding slurry is smaller, and there is less slurry in the free state, resulting in a higher yield stress; the plastic viscosity coefficient of the slurry simultaneously decreases. Therefore, the mixture is difficult to solidify. To ensure the same relative compaction, it is necessary to provide a larger output energy of the vibrating wheel.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec17\" class=\"Section2\"\u003e \u003ch2\u003e4.2 Relationship of relative compaction and rolling times\u003c/h2\u003e \u003cp\u003eThe relationship curve between the number of compaction and the relative compaction of three and four graded roller compacted concrete in each compaction layer is depicted in Fig.\u0026nbsp;5. From Fig.\u0026nbsp;5, the following two patterns can be obtained: ① When the number of VC times is 4\u0026ndash;6, the relative compaction of TGR with different layer thicknesses and vibration forces increases rapidly; after the number of VC times reaches 6, the increase in relative compaction slows down as the number of VC times increases. The number of vibration rolling times increases the relative compaction of FGR with different layer thicknesses and vibration forces.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eweak vibration strong vibration\u003c/p\u003e \u003cp\u003e \u003cb\u003eFigure\u0026nbsp;5\u003c/b\u003e Relationship of relative compaction and rolling times.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec18\" class=\"Section2\"\u003e \u003ch2\u003e4.3 The relationship between relative compaction and compacted layer thickness\u003c/h2\u003e \u003cp\u003eThe relative compaction of the FGR layers dramatically drops as the thickness of the roller-compacted layer increases when the vibration roller operates with a weak vibration; When the vibration roller uses a strong vibration for operation, the relative compaction of the FGR decreases slightly with the increase of the thickness of the roller compacted layer.\u003c/p\u003e \u003cp\u003eThe compaction process of roller compacted concrete is the process in which a vibrating roller propagates constant frequency and oscillation waves from top to bottom to the concrete mixture through a vibrating wheel. Due to the different proportions of various constituent materials and the workability in the mixture, the speed of propagation and degrees of attenuation along depth also vary. The thicker the layer of the mixture, the less vibratory energy is available to the mixture in the lower part of the layer.\u003c/p\u003e \u003cp\u003eThe longer the vibration time required to make the mixture uniform and dense, the more times it will be vibrated and rolled. If the layer is too thick, even if the compaction time is increased, the lower mixture cannot achieve the required density. Therefore, a reasonable layer thickness can achieve the goal of efficient construction and uniform and dense concrete quality.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec19\" class=\"Section2\"\u003e \u003ch2\u003e4.4 Suggestions for construction process parameters of FGR\u003c/h2\u003e \u003cp\u003eBased on comprehensive results of the above experiments, while taking into account a certain relative compaction affluence, the recommended construction process parameters for FGR with layer thicknesses of 0.4m and 0.5m using the machinery, concrete raw materials, and mix proportions used in this experiment are taken down in Table\u0026nbsp;\u003cspan refid=\"Tab5\" class=\"InternalRef\"\u003e5\u003c/span\u003e.\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\u003eSuggestions for construction process parameters of FGR\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=\"char\" char=\".\" 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=\"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 \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eThickness\u003c/p\u003e \u003cp\u003e/m\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eexcitation force\u003c/p\u003e \u003cp\u003e/kN\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eVC value\u003c/p\u003e \u003cp\u003e/s\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eRolling times\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eWalking speed\u003c/p\u003e \u003cp\u003e/km/h\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003eRelative compaction\u003c/p\u003e \u003cp\u003e/%\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e0.4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e395\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e3\u0026thinsp;~\u0026thinsp;5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eNo vibration twice\u0026thinsp;+\u0026thinsp;Vibration 6 times\u0026thinsp;+\u0026thinsp;No vibration twice\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e1.0\u0026thinsp;~\u0026thinsp;1.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e\u0026gt;\u0026thinsp;98.0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e0.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e395\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e3\u0026thinsp;~\u0026thinsp;5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eNo vibration twice\u0026thinsp;+\u0026thinsp;Vibration 8 times\u0026thinsp;+\u0026thinsp;No vibration twice\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e1.0\u0026thinsp;~\u0026thinsp;1.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e\u0026gt;\u0026thinsp;98.0\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":"5. Conclusions","content":"\u003cp\u003eDifferent vibration roller construction process parameters were used to conduct compaction tests on FGR concrete specimens with different mix proportions. The test results were analyzed to propose recommended mix proportions and construction process parameters for FGR concrete. The analysis leads to the following conclusions:\u003c/p\u003e \u003cp\u003e \u003col\u003e \u003cspan\u003e \u003cli\u003e \u003cp\u003eThe water consumption of FGR is controlled at 71kg/m\u0026sup3;~70kg/m\u0026sup3;. Within the range of 4s\u0026thinsp;~\u0026thinsp;6s of VC value, the VC value and air content are both optimal, which can save cementitious materials and effectively reduce the viscosity of FGR, which is beneficial for improving overall working performance and construction efficiency.\u003c/p\u003e \u003c/li\u003e \u003c/span\u003e \u003cspan\u003e \u003cli\u003e \u003cp\u003eIn FGR, as the sand rate increases, the VC value and air content both increase slightly. From the outside of the mixture, it is more appropriate to choose a sand rate of 30%~32%.\u003c/p\u003e \u003c/li\u003e \u003c/span\u003e \u003cspan\u003e \u003cli\u003e \u003cp\u003eWhen the natural coarse aggregate combination ratio (extra large: large: medium: small) is 25:30:25:20, the VC value of the specimen is relatively large. In order to meet the requirements of the \"Technical specification for hydraulic roller compacted concrete process test\" (DL/T 5804\u0026thinsp;\u0026minus;\u0026thinsp;2019, 2019), it is necessary to ensure that the performance of FGR is not inferior to that of TGR, The combination ratio of natural coarse aggregates (extra large: large: medium: small) is suitable at 25:30:25:20.\u003c/p\u003e \u003c/li\u003e \u003c/span\u003e \u003cspan\u003e \u003cli\u003e \u003cp\u003eThe VC value of 3.5s for the FGR mixture is suitable. After 6 rounds of strong vibration and vibration rolling, the surface bleeding is good. The relative compaction can reach over 98%.\u003c/p\u003e \u003c/li\u003e \u003c/span\u003e \u003cspan\u003e \u003cli\u003e \u003cp\u003eUnder the conditions of the machinery, raw materials, and mix proportions used in the experiment, VC should be carried out with an excitation force of 395kN, a walking speed of 1.0\u0026thinsp;~\u0026thinsp;1.5km/h, and a layer thickness of 0.4m. FGR should be rolled twice without vibration, six times with vibration, and two times without vibration. FGR with a layer thickness of 0.5m should be rolled twice without vibration, eight times with vibration, and two times without vibration, relative compaction can be as high as 98% or more for all FGR.\u003c/p\u003e \u003c/li\u003e \u003c/span\u003e \u003c/ol\u003e \u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e \u003ch2\u003eConflicts of Interest\u003c/h2\u003e \u003cp\u003eThe authors declare that they have no conflicts of interest to report regarding the present study.\u003c/p\u003e \u003c/p\u003e\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\u003cp\u003eYan Liang: Investigation, Formal analysis, Writing\u0026ndash;original draft. Yan Shi: Conceptualization, Funding acquisition, Supervision, Investigation, Formal analysis, Writing\u0026ndash;original draft. Cai Wu and Junzhou Huang: Supervision, Investigation. Tianlei Wang and Sheng Peng: Supervision.\u003c/p\u003e\u003ch2\u003eAcknowledgement\u003c/h2\u003e \u003cp\u003eThis research is funded by \u0026lsquo;National Natural Science Foundation of China (CN)\u0026rsquo;-\u0026lsquo;China\u0026rsquo; (52179122, U2040222), \u0026lsquo;Natural Science Foundation of Hubei Province (CN)\u0026rsquo;-\u0026lsquo;China\u0026rsquo; (Grant No. 2022CFB662, 2022CFD026), \u0026lsquo;Tianjin Key Laboratory of Building Green Functional Materials of China (CN)\u0026rsquo; - \u0026lsquo;China\u0026rsquo; (Grant No. JZ-2023003), \u0026lsquo;Key Laboratory of Impact and Safety Engineering (Ningbo University), Ministry of Education of China (CN)\u0026rsquo; - \u0026lsquo;China\u0026rsquo; (Grant No. CJ202306) and their support is gratefully acknowledged.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eJia JS, Chen GX, Ma FL, Li XY (2006) Development level and engineering examples of roller compacted concrete dams. China Water \u0026amp; Power, Beijing\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLuo DN, Lu SH, Hu C, Xue ZX (2022) Experimental and numerical investigation on interlayer fracture process of roller compacted concrete. Constr Build Mater 342:127998\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003e\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.conbuildmat.2022.127998\u003c/span\u003e\u003cspan address=\"10.1016/j.conbuildmat.2022.127998\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSelvam M, Debbarma S, Singh S, Shi XJ (2022) Utilization of alternative aggregates for roller compacted concrete pavements \u0026ndash; A state-of-the-art review. 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Eng Fail Anal 150:107367. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.engfailanal.2023.107367\u003c/span\u003e\u003cspan address=\"10.1016/j.engfailanal.2023.107367\" 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":"Four-graded roller compacted concrete, vibrating compacted (VC) value, natural coarse aggregates, construction technology, mix proportion","lastPublishedDoi":"10.21203/rs.3.rs-4290682/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-4290682/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eIn order to improve construction and production efficiency, and fully leverage the technical and economic advantages of continuous pouring and rapid rise of roller compacted concrete, the four-graded roller compacted concrete was widely used in hydraulic engineering. Based on the characteristics and testing methods of four-graded roller compacted concrete, the multiple sets, the effects of mix proportion, maximum particle size of coarse aggregate, and compaction degree were analyzed. The differences in construction technology between three-graded roller compacted concrete and four-graded roller compacted concrete were compared, and the more suitable construction technology parameters for four-graded roller compacted concrete were obtained. When the water consumption and vibrating compacted (VC) value are within the range of 71kg/m\u0026sup3;~70kg/m\u0026sup3; and 3.5s\u0026thinsp;~\u0026thinsp;6s, respectively, the VC value and air content of four-graded roller compacted concrete are optimal. Choose 30%~32% for sand ratio. The combination ratio of natural coarse aggregates (extra large: large: medium: small) adopts 25: 30: 25: 20. The VC value of 3.5s is suitable. After 6 times of heavy rolling and vibration rolling, the surface has a good slurry state, with a relative compaction degree exceeding 98%. The vibration force is 395kN, and the working speed is 1.0\u0026thinsp;~\u0026thinsp;1.5km/h. The suggestions as follows: when the layer thickness is 0.4m, the four-graded roller compacted concrete should be rolled twice without vibration, six times with vibration, and two times without vibration; When the layer thickness is 0.5m, the four-graded roller compacted concrete should be rolled twice without vibration, eight times with vibration, and two times without vibration.\u003c/p\u003e","manuscriptTitle":"Research on the mix proportion and on-site construction technology of a four-graded roller compacted concrete","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2024-04-24 20:22:28","doi":"10.21203/rs.3.rs-4290682/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":"8e0b69b9-8262-4af5-bb52-d7ed4173bb9c","owner":[],"postedDate":"April 24th, 2024","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2024-05-31T06:52:40+00:00","versionOfRecord":[],"versionCreatedAt":"2024-04-24 20:22:28","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-4290682","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-4290682","identity":"rs-4290682","version":["v1"]},"buildId":"qtupq5eGEP_6zYnWcrvyt","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}