不同粒径再生粗骨料二级配混凝土力学性能试验研究

摘要

In order to study the influences of coarse aggregate particle size on the mechanical properties of recycled concrete,the recycled concrete specimens with two gradation are made with recycled coarse aggregate,in which,the particle size and substitution rate of recycled coarse aggregate are taken as the variables and the recycled coarse aggregate with particle sizes of 5-20 mm,20-30 mm and 5-30 mm are used respectively.The uniaxial compressive tests are conducted to analyze the mechanical properties of these recycled concrete specimens.The test results show that:(a) under same replacement rate,the compressive strength of two-graded recycled concrete with recycled coarse aggregate particle size of 5-30 mm is higher than that with recycled coarse aggregate particle size of 5-20 mm or 20-30 rm;(b) when the replacement rate of recycled coarse aggregate is 30％,the compressive strength of two-graded recycled aggregate concrete is the largest,and the splitting tensile strength is the highest when the substitution rate is 40％;and (c) the recycled coarse aggregate with particle size of 20-30 mm is the main influence factor to the compressive strength and splitting tensile strength of two-graded recycled concrete.When the recycled coarse aggregate is completely graded and the substitution rate is 30％ to 40％,the compressive strength and splitting tensile strength of two-graded recycled aggregate concrete are the biggest.%为研究粗骨料粒径对再生混凝土力学性能的影响,以再生粗骨料粒径和取代率为变量,用5～20、20～30mm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,对试件进行混凝土单轴抗压试验,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.试验结果表明: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;再生粗骨料取代率为30％时,二级配再生混凝土的抗压强度最大,取代率为40％时劈裂抗拉强度最大;影响二级配再生混凝土抗压强度及劈裂抗拉强度的主要是粒径为20～30 mm的再生粗骨料.再生粗骨料全级配取代,且取代率为30％～40％时,二级配再生混凝土的抗压强度及劈裂抗拉强度最大.