混凝土初始缺陷对其弯曲性能的影响研究

Study on the impact for bending properities of concrete under different initial defections

在同一种配合比混凝土试件中掺入4种不同含量的引气剂,以模拟混凝土的初始缺陷,并在CMT-100微机控制电子万能试验机上进行混凝土试件的四点弯曲试验,测出了混凝土弯曲过程的应力-应变曲线,研究了不同缺陷含量对混凝土的抗弯强度、变形特性和损伤特性的影响。试验结果表明:随着掺入引气剂含量的增加,混凝土的应力-应变曲线逐渐平缓,混凝土内部的初始损伤相应增加,其抗弯强度均随之降低,而峰值应变基本保持不变。

Initial defections were simulated through mixing different quantities of air entraining agent into four test samples of the same concrete, and then four- point bending tests of plain concrete specimens were carded out by using a static -dynamic test machine.The relation of strain - strain curves of the concrete were obtained, and the effects of different initial defections on bending strengths, strain - strain curves and damage behaviors of concrete were investigated.It was found that the initial damage of concrete were increasing and the strain - strain curves were began to flatten; the bending strengths of concrete were decreased with the increasing quantities of air entraining agent,but the peak strains remained unchanged.