循环荷载作用下泡沫混凝土强度特性研究

Study on the strength characteristics of foam concrete under cyclic loading

泡沫混凝土作为一种新型材料,因其轻质性而得到广泛的应用,通过循环荷载试验开展路用泡沫混凝土强度特性研究。根据相关规范及现场实际情况,循环荷载试验方案中采用上下限应力0.1~0.7 MPa,累计最大疲劳荷载120万次。测试获得了不同疲劳试验过程下,泡沫混凝土试样的残余强度。试验结果表明:泡沫混凝土疲劳测试中的残余强度随着疲劳次数的增加而降低,且在40万次荷载循环以内残余强度下降明显,在40~120万次中泡沫混凝土的强度衰减比较缓慢,当120万次疲劳试验下的试样残余强度下降了24%。基于HYMOSTRUC3D模型,采用微观力学计算方法建立了微观结构数值计算模型,模拟得到含微裂缝的轻质混凝土材料在循环荷载作用下泡沫混凝土力学性能,并与试验结果进行了拟合及预测。

The foam concrete,as a new type of material,has been widely used because of its lightweight.This paper studied the strength characteristics of foam concrete by cyclic loading test.According to the relevant codes and the actual situation in the field,the stresses of 0.1~0.7 MPa were adopted in the cyclic load test scheme,and the cumulative maximum fatigue load was 1.2 million times.The residual strength of foam concrete specimens under different fatigue tests was obtained.The test results show that the residual strength of the foam concrete fatigue test decreases with the increase of fatigue times,and the residual strength decreases obviously during the 400 thousand load cycles.The strength decay of foam concrete is slower in 400 thousand-1 million 200 thousand times,and the residual strength of the sample decreases by 24%when the 1 million 200 thousand fatigue test is carried out.Based on the HYMOSTRUC3D model,a microstructural numerical calculation model is established by micromechanics calculation.The mechanical properties of lightweight concrete with micro cracks under cyclic loading are simulated,and the experimental results are fitted and predicted.