利用大型多功能静动力三轴仪进行了外掺氧化镁微膨胀混凝土在不同应变速率下的单轴抗压性能试验。对微膨胀混凝土的物理力学参数进行了统计分析,研究了加载速率、氧化镁活性以及掺量对微膨胀混凝土动态力学特性的影响。结果表明:外掺MgO微膨胀混凝土表现出明显的率效应,抗压强度与加载速率成正比;在应变速率一定时,氧化镁掺量与混凝土抗压强度成正比,氧化镁活性对混凝土强度影响不大。在此基础上,进行应力应变曲线分析,当MgO掺量为9%时,混凝土的塑性改善最为明显。最后,构建了微膨胀混凝土动态损伤模型,并对所建模型的适用性进行了验证。
The uniaxial compressive test of micro expansive concrete added with MgO under different loading rates were completed u- sing a large multi - function static and dynamic force triaxial apparatus. Statistical of analysis about physical and mechanical parameters of micro expansive concrete was carried out. The influence of strain rate, MgO activity and content on the compressive strength of micro expansive concrete was researched.The results show that micro expansive concrete added with MgO exhibits obvious rate effects, the compressive strength of micro expansive concrete is proportional to the strain rate. In a certain strain rate, the compressive strength is proportional to MgO content, MgO activity had little effect .on the compressive strength of micro expansive concrete. On this basis, anal- ysis of the stress strain curve was carried out,when the dosage of MgO is 9% ,the improvement of the ductility of concrete is the most obvious.Finally,constructs the dynamic damage model of micro expansive concrete, and the applicability of the model was verified.