再生透水混凝土应力—应变全曲线试验研究

Study on complete stress-strain curve of recycled pervious concrete

以再生骨料替代率(0、30%、70%、100%)和养护龄期(3 d、7 d、28 d)为变化参数,完成了不同龄期不同再生粗骨料替代率下再生混凝土的单轴受压应力—应变全曲线试验,分析了不同养护龄期及不同再生骨料替代率对再生透水骨料混凝土的破坏形态、弹性模量、应力—应变全曲线斜率及发展趋势的影响。研究表明,再生透水混凝土的破坏形态和普通混凝土相似,再生骨料替代率对破坏裂纹有影响,替代率越高裂纹越宽,龄期对破坏面与荷载垂线方向夹角相关,龄期越长夹角越小,不同龄期不同替代率下透水混凝土的应力—应变曲线和普通混凝土的类似,分为上升和下降两个部分,龄期对上升部分影响显著,龄期越长应力—应变曲线斜率越大,再生骨料替代率对下降部分影响较大,再生骨料增加试样弹性模量变低,下降曲线变陡。且再生透水混凝土的棱柱体抗压强度与立方体抗压强度的比值高于普通混凝土。

Taking the replacement rate of recycled aggregate(0,30%,70%,100%)and curing period(3 d,7 d,28 d)as the changing parameters,the complete stress-strain curve test of recycled concrete under uniaxial compression under different ages and different replacement rates of recycled coarse aggregate was completed.The effects of different curing ages and different replacement rates of recycled aggregate on failure modes,elastic modulus,slope of the complete stress-strain curve and development trend of recycled pervious concrete were analyzed.The results show that the failure mode of recycled pervious concrete is similar to that of ordinary concrete,and the replacement rate of recycled aggregate has an effect on the failure crack,the higher the replacement rate,the wider the crack;The angle between the failure surface and the vertical direction of the load is related to the age,the longer the age,the smaller the angle;The stress-strain curve of concrete with different replacement rates at different ages is similar to that of ordinary concrete,there are two parts:rising part and declining part.Age has a significant effect on the rising part,the longer the age,the greater the slope of stress-strain curve;The replacement rate of recycled aggregate has a greater impact on the declining part.With the increase of recycled aggregate,the elastic modulus of the sample becomes lower and the declining curve becomes steeper.The ratio of prism compressive strength to cube compressive strength of recycled pervious concrete is higher than that of ordinary concrete.