不同再生次数混凝土抗压强度及其尺寸效应分析

Analysis of compressive strength and size effect of concrete with different recycling times

为实现混凝土结构循环利用,研究了不同再生次数粗骨料的物理性能以及混凝土立方体和棱柱体抗压强度,并对抗压强度尺寸效应进行了分析。试验表明:再生粗骨料的各项物理性能均比天然粗骨料差,且随着再生次数的增加而变差;同类型混凝土试件的抗压破坏形态和裂纹发展规律随再生次数的变化基本相同;每种尺寸的混凝土抗压强度随再生次数变化情况均为普通混凝土>二次再生混凝土>三次再生混凝土>一次再生混凝土;通过引入尺寸效应度来分析混凝土抗压强度尺寸效应的大小,得出二次和三次再生混凝土的抗压强度尺寸效应要低于普通混凝土,一次再生混凝土的抗压强度尺寸效应略高于普通混凝土。

In order to realize the recycling of concrete structure,the physical properties of coarse aggregate with different recycling times and the compressive strength of concrete cube and prism were studied,and the size effect of compressive strength was analyzed.The experimental results show that the physical indexes of recycled coarse aggregate are worse than those of natural coarse aggregate,and become worse with the increase of recycling times.The compressive failure mode and crack development law of the same type of concrete specimens are basically the same with the number of regeneration.The change of compressive strength of concrete of each size with the number of recycling is ordinary concrete>secondary recycled concrete>tertiary recycled concrete>primary recycled concrete.By introducing the size effect degree to analyze the size effect of compressive strength of concrete,it is concluded that the size effect of compressive strength of secondary recycled concrete and tertiary recycled concrete is lower than that of ordinary concrete.The cube compressive strength size effect of primary recycled concrete is slightly higher than that of ordinary concrete.