混凝土立方体抗压强度速率特性尺寸效应理论研究

The oretical study on size effect of concrete cube compressive strength considering strain rate effect

为了研究尺寸效应和率相关性对混凝土力学性能的影响,对三种尺寸(70,100,150mm)共计228个混凝土立方体试块在四种应变速率(1×10^(–5),1×10^(–4),1×10^(–3),1×10^(–2)s)下进行试验研究。试验结果表明:在相同的应变速率下,混凝土的峰值应力是随着试块尺寸的增大而减小的;相同尺寸下,混凝土峰值应力随着应变速率的增大而增大。利用试验数据对基于统计学的Weibull尺寸效应公式和基于断裂力学的Bazant尺寸效应公式进行验证和修正,通过对试验数据拟合得到了考虑应变速率影响的混凝土抗压强度尺寸效应公式。

In order to study the influence of size effect and dynamic rate relevance on the mechanical properties of concrete,a total of 228 concrete cube test blocks of three sizes(70,100,150 mm)were tested and studied under four strain rates(1×10^(–5),1×10^(–4),1×10^(–3),1×10^(–2)s).The test results show that under the same strain rate,the peak stress of concrete decreases with the increase of the size;under the same size,the peak stress of concrete increases with the increase of the strain rate.The Weibull size effect formula based on statistics and the Bazant size effect formula based on fracture mechanics were verified and modified by using the test data,and the size effect formula of concrete compressive strength considering the effect of strain rate was obtained by fitting the test data.