模型再生混凝土单轴受压动态力学特性试验

试验设计了再生粗骨料取代率为100%的模型再生混凝土（MRC）、模型普通混凝土（MC）、再生粗骨料取代率55%的模型再生混凝土（MCP）和模型砂浆（MM）4种试件，在不同应变速率下进行单轴受压试验。研究表明：随着加载应变速率的提高，试件应力-应变曲线形状相似，峰值应力和弹性模量表现出增大的趋势，峰值应变的变化无明显规律；MRC、MC、MCP试件破坏时裂缝最先出现在界面区附近，然后逐渐发展直至贯通，随着应变速率的提高，裂缝较宽且开展更快，试件完全断裂成若干碎块；模型再生混凝土静态强度越低，峰值应力和弹性模量增长越大，动态效应越显著；再生粗骨料取代率为55%时，峰值应力和弹性模量增长最大；模型砂浆试件的动态效应最显著，模型普通混凝土和模型再生混凝土次之，且相差不大。

Experimental study on dynamic mechanical behavior of modeled recycled aggregate concreteunder uniaxial compression

Four kinds of specimens, including modeled recycled aggregate concrete (MRC), modeled natural aggregate concrete(MC), modeled recycled aggregate concrete with 55% replacement ratio of recycled coarse aggregate(MCP) and modeled mortar (MM), were uniaxially loaded and tested at different strain rates to investigate the dynamic mechanical behavior of recycled aggregate concrete. It is found that, with the increase of strain rate, the shape of stress-strain curve displays almost the same, strength and elastic modulus increase, whereas there is no clear tendency for the peak strain. For MRC, MC and MCP, cracks firstly appear in the interface zone, and then develop gradually till the failure of the specimen. With the increase of strain rate, cracks become wider and propagate more rapidly until finally the specimen breaks into small pieces. The lower the strength of recycled aggregate concrete is, the greater the improvement of peak stress and elastic modulus are, and the more significant the dynamic effects are. The increase of peak stress and elastic modulus is the highest when the replacement ratio of recycled coarse aggregate reaches 55% in all replacement ratio cases. Dynamic effects of mortar are more significant than those of natural aggregate concrete and recycled aggregate concrete.