冻融循环后再生混凝土基本力学性能试验

Experimental study on the basic mechanical property of recycled concrete after freeze-thaw

为了研究再生混凝土冻融循环后的力学性能变化,通过对再生混凝土的冻融循环试验和冻融循环后的应力-应变全曲线试验,分析了再生粗骨料掺量和冻融循环次数对再生混凝土重量损失率、相对动弹性模量损失率、峰值应力、峰值应变、弹性模量、横向变形系数等力学性能的影响。试验结果表明:随着再生粗骨料掺量和冻融次数增加,再生混凝土重量损失率、相对动弹性模量损失率增加;峰值应力、弹性模量减小;峰值应变在再生粗骨料掺量低时随冻融循环次数的增加而降低,在再生粗骨料掺量高且冻融循环次数大于100次后随冻融循环次数的增加而增加。此外,还建立了冻融循环后再生混凝土应力-应变全曲线公式。再生混凝土抗冻性随再生粗骨料掺量和冻融循环次数增加而降低。再生混凝土抗冻性比普通混凝土差。为再生混凝土在冻融环境下的工作机理与计算模式研究提供依据。

In order to study on the basic mechanical property of recycled concrete after freeze-thaw.By freeze-thaw cycle test and stress-strain curves test,the influence of freeze-thaw cycles and recycled coarse aggregate to the weight loss rate and the relative dynamic elastic modulus loss rate,peak stress,peak strain,elastic modulus,transverse deformation coefficient and other mechanical properties was analyzed.The results show that the mechanical properties of recycled concrete are deteriorated by freeze-thaw.With the increase of freeze-thaw frequency and recycled aggregate,the weight loss rate and the relative dynamic elastic modulus loss rate will increase,the peak stress and the elastic modulus will be reduced;When the dosage of recycled aggregate is low,peak strain reduce with the increase of freeze-thaw cycles frequency;When the dosage of recycled aggregate is high and freeze-thaw frequency is over 100 times,the peak strain increases with the increase of freeze-thaw frequency.In addition,this dissertation established the formulas of stress-strain whole curves of recycled concrete after freeze-thaw cycles.The frost resistance of recycled concrete will be reduced with the increases of recycled coarse aggregate and the freeze-thaw frequency.Frost resistance of recycled concrete is worse than ordinary concrete.It can offer reference for behavior and calculation model of recycled concrete structures under freeze-thaw environment.