Theoretical model of drying shrinkage behavior of recycled coarse aggregate concrete
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摘要: 为研究再生粗骨料混凝土的干燥收缩特性,收集了现有12项研究与32组收缩数据并进行了比较,试验时间跨度为41~480 d,分析参数包括水灰比(0.36~0.68)、普通混凝土抗压强度(27~60 MPa)、再生粗骨料替换率(20%~100%)、相对湿度(43%~65%)、湿养护时间(1~28 d)和测量收缩的时间(41~480 d);通过比较试验数据和理论预测结果,利用基于天然骨料混凝土干燥收缩试验数据的多个统计指标,评估了现有ACI 209R-92模型、Bazant-Baweja B3模型以及FIB MC2010模型;采用基于Fathifazl等研究的方法来评估混凝土的干燥收缩增量;通过上述选定模型来评估再生粗骨料混凝土的干燥收缩率的增量,并使用评价残差、欧洲国际混凝土委员会(CEB)变异系数、CEB均方差与CEB偏差等统计指标评价了试验数据。研究结果表明:当将已知收缩行为的天然骨料混凝土的部分或全部粗骨料替换为已知残留砂浆含量的再生粗骨料,可以最准确地预测总收缩的演变;通过将残余砂浆系数应用于天然骨料混凝土的实测收缩量,可以相对准确地预测再生骨料混凝土的收缩;当再生粗骨料混凝土的替代率为20%~33%时,残余砂浆系数为1.03~1.08,当再生粗骨料混凝土的替代率为50%时,残余砂浆系数为1.07~1.16,即再生骨料混凝土的干燥收缩率比天然骨料混凝土的干燥收缩率增加了约16%或更小;当再生粗骨料混凝土的替代率为100%时,残余砂浆系数为1.18~1.76;当天然骨料混凝土的替代率大于50%时,再生粗骨料混凝土的干燥收缩率的增加相比天然骨料混凝土的干燥收缩率的增加更明显。由此可见,当前的研究方法可用于利用扩展的数据库进一步改进再生粗骨料混凝土干燥收缩行为的理论预测。Abstract: To investigate the drying shrinkage behavior of recycled coarse aggregate concrete, 12 studies and 32 sets of shrinkage data were collected and compared. The test period was between 41 and 480 d, and the analysis parameters were as follows: the water-cement ratio (0.36-0.68), compressive strength of normal concrete (27-60 MPa), replacement ratio of recycled coarse aggregate (20%-100%), relative humidity (43%-65%), time for wet cure (1-28 d), and time of shrinkage measurement (41-480 d). Three existing theoretical models, such as the ACI 209R-92 model, Bazant-Baweja B3 model, and fib MC2010 model, were evaluated by comparing the test data with the theoretical predictions using multiple statistical indicators based on the experimental drying shrinkage data of natural aggregate concrete. The approach proposed by Fathifazl et al. was used to evaluate the increase in the drying shrinkage of concrete. The increments of the drying shrinkage rate of recycled coarse aggregate concrete were also evaluated by the three selected models, and the experimental data were evaluated by the statistical indicators including the residual evaluation, as well as the variation coefficient, mean square error, and mean deviation of Comité Euro-International du Béton (CEB). Research results show that the most accurate predictions of the total shrinkage evolution are possible when part or all coarse aggregates of natural aggregate concrete with known shrinkage behavior is replaced with the recycled coarse aggregate with known residual mortar content. When the residual mortar coefficient is applied to the measured shrinkage of natural aggregate concrete, a relatively accurate prediction of the shrinkage of recycled coarse aggregate concrete is possible. The residual mortar coefficient ranges from 1.03 to 1.08 when the replacement ratio of recycled coarse aggregate is 20%-33%, and it is between 1.07 and 1.16 when the replacement ratio is 50%. In other words, the increase in the drying shrinkage rate of recycled aggregate concrete over that of the natural aggregate concrete is about 16% or smaller. When the replacement ratio of recycled aggregate concrete is 100%, the residual mortar coefficient ranges from 1.18 to 1.76. When the replacement ratio of natural aggregate concrete is greater than 50%, the increase in the drying shrinkage rate of recycled coarse aggregate concrete is more significant than that of the natural aggregate concrete. It can be seen that the current research methodology can be used to further improve the theoretical prediction of the drying shrinkage behavior of recycled coarse aggregate concrete using an expanded database.
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Table 1. Summary of shrinkage research collected for this study
Data Batch w/c RCA -absorption, density, RMC Hardened concrete Replacement ratio of RCA/% Shrinkage SRM fcm28/MPa E/GPa Measured period(started, RH) Domingo[9] Replacement ratios of RCAs are 20%, 50%, 100% 0.50 4/8 mm-5.19%, 2 460 kg·m-3, 31.5%
8/20 mm- 5.19%, 2 460 kg·m-3, 18.0%47.4 32.4 20 252 d (7 d, 23 ℃, 65%) 1.03
1.09
1.2047.3 33.5 50 54.8 30.3 100 Duan[11] C30-RA1, RA2, RA3 0.68 RA1 (5/10 mm)-3.13%, 2 540 kg·m-3, 14.3%
RA1 (10/20 mm)-3.47%, 2 450 kg·m-3, 24.3%
RA2 (5/10 mm)-7.09%, 2 350 kg·m-3, 37.2%
RA2 (10/20 mm)-5.66%, 2 370 kg·m-3, 34.0%
RA3 (5/10 mm)-7.77%, 2 370 kg·m-3, 63.8%
RA3 (10/20 mm)-5.77%, 2 360 kg·m-3, 61.1%27.7-35.0 24.5-28.9 100 112 d (28 d, 23 ℃, 55%) 1.34-1.76 C45-RA1, RA2, RA3 0.51 42.0-47.6 24.6-29.4 100 1.35-1.78 C60-RA1, RA2, RA3 0.44 53.2-60.0 29.5-34.8 100 1.32-1.70 Fathifazl[10] CM, CV 0.45 RCA-M, 5.4%, 2 420 kg·m-3, 41%
RCA-V, 3.3%, 2 500 kg·m-3, 23%43.9-45.9 100 224 d (28 d, 23 ℃, 50%) 1.18-1.30 EM 41.4 64 1.26 EV 44.8 74 1.17 He[15] RCA30 0.40 RCA30, 6.43%, 2 281 kg·m-3, 48.2%
RCA80, 4.75%, 2 386 kg·m-3, 41.3%33.0 23.5 100 180 d (7 d, 20 ℃, 60%) 1.69 RCA80 42.0 29.0 100 1.54 Zhang[16] RAC-C50 0.45 5.1%, 2 795 kg·m-3, 40.0% 47.9 30.5 50 480 d (28 d, 20 ℃, 60%) 1.16 RAC-C100 44.0 26.3 100 1.46 Gholampur[12] NC-40 0.50 RCA-40, 5.9%, 2 240 kg·m-3, 48% 32.0 26.7 100 450 d (3 d, 23 ℃, 60%) 1.19 Chinzorigt-1[13] RAC-50, CRAC-50
RAC-100, CRAC-1000.50 RA, 3.84%, 2 430 kg·m-3, 24.2%
CRA, 3.14%, 2 490 kg·m-3, 24.2%27.0-33.1 23.6-25.4 50 180 d (1 d, 20 ℃, 60%) 1.07 27.5-34.4 23.8-25.2 100 1.19 Chinzorigt-2[14] RC-100 0.50 RCA, 3.84%, 2 430 kg·m-3, 24.2% 33.8 26.4 100 300 d (1 d, 20 ℃, 60%) 1.18 Yang-1[26] Mix series 0.38 RCA (5/32 mm), 4.45%, 2 350 kg·m-3, 35.5% 40.2 25.2 50 105 d (7 d, 20 ℃, 50%) 1.16 Yang-2[27] Replacement ratio of RCA is 40% 0.41 RCA (5/25 mm), 4.51%, 2 490 kg·m-3, 32.0% 43.9 20.3 40 41 d (7 d, 20 ℃, 60%) 1.08 Yang-3[28] Replacement ratios of RCAs are 68%, 33% 0.39 RCA (5/20 mm), 4.53%, 2 480 kg·m-3, 40.1% 41.9, 48.1 24.8, 25.8 68, 33 54 d (7 d, 20 ℃, 43%) 1.18
1.08Yang-4[29] Replacement ratios of RCAs are 25%, 50% 0.36 RP (5/20 mm), 2.62%, 2 600 kg·m-3, 20.0% 31.6, 30.8 27.7, 26.3 25, 50 145 d (7 d, 20 ℃, 60%) 1.03
1.07Table 2. Summary and rating of theoretical models for shrinkage strain of NAC (number of data point is 164)
Indicator ACI 209 fib MC2010 B3 Residuals Positive/% 47.0 50.6 32.7 Negative/% 53.0 49.4 67.3 Rating 2 1 3 CEB COV VCEB 0.311 0.391 0.445 Rating 1 2 3 CEB MSE FCEB/% 65.4 53.1 39.7 Rating 3 2 1 CEB mean deviation MCEB 1.150 1.150 0.785 Rating 1 1 3 Total rating 7 6 10 Table 3. Comparison between predicted shrinkage strains vs. test data
Indicator NAC data times SRM vs. RAC data Shrinkage data from ACI 209 times SRM vs. RAC data Shrinkage data from MC 2010 times SRMvs. RAC data Shrinkage data from B3 times SRM vs. RAC data Residuals Positive/% 77.8 67.4 62.4 45.5 Negative/% 22.2 32.6 37.6 54.5 Rating 4 3 2 1 CEB COV VCEB 0.228 0.371 0.580 0.363 Rating 1 3 4 2 CEB MSE FCEB/% 28.4 73.0 80.2 33.8 Rating 1 3 4 2 CEB mean deviation MCEB 1.141 1.411 1.469 0.930 Rating 2 3 4 1 Total rating 8 12 14 6 -
[1] MAO Yu-guang, LIU Jian-hui, SHI Cai-jun. Autogenous shrinkage and drying shrinkage of recycled aggregate concrete: a review[J]. Journal of Cleaner Production, 2021, 295: 126435. doi: 10.1016/j.jclepro.2021.126435 [2] WANG Qing-he, GENG Yue, WANG Yu-yin, et al. Drying shrinkage model for recycled aggregate concrete accounting for the influence of parent concrete[J]. Engineering Structures, 2020, 202: 109888. doi: 10.1016/j.engstruct.2019.109888 [3] WANG Bo, YAN Li-bo, FU Qiu-ni, et al. A comprehensive review on recycled aggregate and recycled aggregate concrete[J]. Resources, Conservation and Recycling, 2021, 171: 105565. doi: 10.1016/j.resconrec.2021.105565 [4] BEHERA M, MINOCHA A K, BHATTACHARYYA S K. Flow behavior, microstructure, strength and shrinkage properties of self-compacting concrete incorporating recycled fine aggregate[J]. Construction and Building Materials, 2019, 228: 116819. doi: 10.1016/j.conbuildmat.2019.116819 [5] TOŠIĆ N, DE LA FUENTE A, MARINKOVIĆ S. Shrinkage of recycled aggregate concrete: experimental database and application of fib Model Code 2010[J]. Materials and Structures, 2018, 51(5): 126. doi: 10.1617/s11527-018-1258-0 [6] MANZI S, MAZZOTTI C, BIGNOZZI M C. Short and long-term behavior of structural concrete with recycled concrete aggregate[J]. Cement and Concrete Composites, 2013, 37: 312-318. doi: 10.1016/j.cemconcomp.2013.01.003 [7] BRAVO M, DE BRITO J, EVANGELISTA L, et al. Durability and shrinkage of concrete with CDW as recycled aggregates: benefits from superplasticizer's incorporation and influence of CDW composition[J]. Construction and Building Materials, 2018, 168: 818-830. doi: 10.1016/j.conbuildmat.2018.02.176 [8] ISMAIL S, RAMLI M. Mechanical strength and drying shrinkage properties of concrete containing treated coarse recycled concrete aggregates[J]. Construction and Building Materials, 2014, 68: 726-739. doi: 10.1016/j.conbuildmat.2014.06.058 [9] DOMINGO-CABO A, LÁZARO C, LÓPEZ-GAYARRE F, et al. Creep and shrinkage of recycled aggregate concrete[J]. Construction and Building Materials, 2009, 23(7): 2545-2553. doi: 10.1016/j.conbuildmat.2009.02.018 [10] FATHIFAZL G, RAZAQPUR A G, ISGOR O B, et al. Creep and drying shrinkage characteristics of concrete produced with coarse recycled concrete aggregate[J]. Cement and Concrete Composites, 2011, 33(10): 1026-1037. doi: 10.1016/j.cemconcomp.2011.08.004 [11] GHOLAMPOUR A, OZBAKKALOGLU T. Time-dependent and long-term mechanical properties of concretes incorporating different grades of coarse recycled concrete aggregates[J]. Engineering Structures, 2018, 157: 224-234. doi: 10.1016/j.engstruct.2017.12.015 [12] GHOLAMPOUR A, OZBAKKALOGLU T. Time-dependent and long-term mechanical properties of concretes incorporating different grades of coarse recycled concrete aggregates[J]. Engineering Structures, 2018, 157: 224-234. doi: 10.1016/j.engstruct.2017.12.015 [13] CHINZORIGT G, CHOI D, ENKHBOLD O, et al. Strength, shrinkage and creep of concrete including CO2 treated recycled coarse aggregate[J]. Journal of Asian Concrete Federation, 2018, 4(2): 89-102. doi: 10.18702/acf.2019.1.4.2.89 [14] CHINZORIGT G, LIM M K, YU M, et al. Strength, shrinkage and creep and durability aspects of concrete including CO2 treated recycled fine aggregate[J]. Cement and Concrete research, 2020, 136: 106062. doi: 10.1016/j.cemconres.2020.106062 [15] HE Zhi-hai, HU Hai-bo, CASANOVA I, et al. Effect of shrinkage reducing admixture on creep of recycled aggregate concrete[J]. Construction and Building Materials, 2020, 254: 119312. doi: 10.1016/j.conbuildmat.2020.119312 [16] ZHANG Huan, WANG Yu-yin, LEHMAN D E, et al. Time dependent drying shrinkage model for concrete with coarse and fine recycled aggregate[J]. Cement and Concrete Composites, 2020, 105: 103426. doi: 10.1016/j.cemconcomp.2019.103426 [17] TAM V W Y, KOTRAYOTHAR D, XIAO Jian-zhuang. Long-term deformation behaviour of recycled aggregate concrete[J]. Construction and Building Materials, 2015, 100: 262-272. doi: 10.1016/j.conbuildmat.2015.10.013 [18] SILVA R V, DE BRITO J, DHIR R K. Prediction of the shrinkage behavior of recycled aggregate concrete: a review[J]. Construction and Building Materials, 2015, 77: 327-339. doi: 10.1016/j.conbuildmat.2014.12.102 [19] MEDJIGBODO S, BENDIMERAD A Z, ROZIÈRE E, et al. How do recycled concrete aggregates modify the shrinkage and self-healing properties?[J]. Cement and Concrete Composites, 2018, 86: 72-86. doi: 10.1016/j.cemconcomp.2017.11.003 [20] XIAO Jian-zhuang, LI Wen-gui, SUN Zhi-hui, et al. Properties of interfacial transition zones in recycled aggregate concrete tested by nanoindentation[J]. Cement and Concrete Composites, 2013, 37: 276-292. doi: 10.1016/j.cemconcomp.2013.01.006 [21] THOMAS C, SETIÉN J, POLANCO J A, et al. Durability of recycled aggregate concrete[J]. Construction and Building Materials, 2013, 40: 1054-1065. doi: 10.1016/j.conbuildmat.2012.11.106 [22] American Concrete Institute. Guide for modeling and calculating shrinkage and creep in hardened concrete[R]. Farmington Hills: American Concrete Institute, 2008. [23] HEDJAZI S, RAHAI A, SENNAH K. Evaluation of creep effects on the time-dependent deflections and stresses in prestressed concrete bridges[J]. Bridge Structures, 2007, 3(2): 119-132. doi: 10.1080/15732480701496629 [24] AL-MANASEER A, LAM J. Statistical evaluation of shrinkage and creep models[J]. ACI Materials Journal, 2005, 102(3): 170-176. [25] WALRAVEN J. Fib model code for concrete structures 2010: mastering challenges and encountering new ones[J]. Structural Concrete, 2013, 14(1): 3-9. doi: 10.1002/suco.201200062 [26] YANG S, LEE H. Freeze-thaw resistance and drying shrinkage of recycled aggregate concrete proportioned by the modified equivalent mortar volume method[J]. International Journal of Concrete Structures and Materials, 2017, 11(4): 617-626. doi: 10.1007/s40069-017-0216-5 [27] YANG S, LEE H. Structural performance of reinforced RCA concrete beams made by a modified EMV method[J]. Sustainability, 2017, 9(1): 131. doi: 10.3390/su9010131 [28] YANG S, LIM Y. Mechanical strength and drying shrinkage properties of RCA concretes produced from old railway concrete sleepers using by a modified EMV method[J]. Construction and Building Materials, 2018, 185: 499-507. doi: 10.1016/j.conbuildmat.2018.07.074 [29] YANG S, LEE H. Drying shrinkage and rapid chloride penetration resistance of recycled aggregate concretes using cement paste dissociation agent[J]. Materials, 2021, 14(6): 1478. doi: 10.3390/ma14061478 [30] NEVILLE A M. Properties of concrete-an overview[J]. Concrete International, 1986, 8(2): 20-26.