不同粒径再生粗骨料混凝土单轴受压应力-应变关系试验研究

Experimental study on stress-strain relationship of recycled coarse aggregate concrete with different particle size under uniaxial compression

研究了粗骨料粒径对再生混凝土力学性能的影响,为再生混凝土工程中合理选取再生粗骨料粒径及取代率提供参考和依据。以再生粗骨料粒径和取代率为变量,用5~20 mm、20~30 mm及5~30 mm粒径范围内的再生粗骨料制作了不同取代率的二级配再生混凝土试件,利用混凝土单轴抗压的试验方法,分析了不同再生粗骨料粒径以及不同取代率再生混凝土的力学性能。实验结果表明:再生混凝土的弹性模量随取代率的增大而减小;相同取代率下,再生粗骨料粒径为5~30 mm的二级配再生混凝土的抗压强度比粒径为5~20 mm或20~30 mm的二级配再生混凝土的抗压强度高;粒径为20~30 mm的再生粗骨料对二级配再生混凝土力学性能的影响最大。再生粗骨料全级配取代,且取代率为30%时二级配再生混凝土的抗压强度最大。

The influence from the coarse aggregate particle size on the mechanical property of the recycled concrete is studied herein,so as to provide a reference and basis for reasonably selecting the particle size of the recycled coarse aggregate and its replacement rate. Taking the particle size of the recycled coarse aggregate and its replacement rate as the variables,the secondary aggregate grading concrete samples with different replacement rates are made by the recycled aggregates within the particle range of 5 - 20 mm,20 - 30 mm and 5 - 30 mm,and then the mechanical properties of the recycled concretes with different recycled coarse aggregates and replacement rates are analyzed with the relevant uniaxial compression experiments. The experiment result shows that the elastic modulus of the recycled concrete decreases along with the increase of the replacement rate. Under the same replacement rate,the compressive strength of the secondary aggregate grading concrete with the particle size of the recycled coarse aggregate of 5 - 30 mm is higher than that of the secondary aggregate grading concrete with the particle size of the recycled coarse aggregate of 5 - 20 mm or 20 - 30 mm,while the influence from the particle size of the recycled coarse aggregate of 20 - 30 mm on the compressive strength of the secondary aggregate grading concrete is the largest. The compressive strength of the secondary aggregate grading concrete is the largest when its recycled aggregate is replaced through full gradation with the replacement rate of 30%.