引气再生混凝土抗冻耐久性试验与损伤模型

通过对再生粗骨料掺量为0、25%、50%、75%、100%的C30再生混凝土和C30引气再生混凝土进行抗冻耐久性试验,得到质量损失率、动弹性模量的性能指标在冻融循环过程中的变化规律。基于Aas-Jakobsen损伤模型,定义实际应力比的相对差值为损伤变量,以相对动弹性模量作为损伤变量来拟合抗冻性能参数α,并对得到的冻融损伤关系进行验证。结果表明:掺量为50%的再生混凝土和普通再生混凝土的抗冻性能相近,较其他掺量的更优;同时,在再生混凝土中添加引气剂,有利于改善抗冻性能。从损伤模型计算值与实测值来看,二者基本相符,验证了损伤模型的合理性。

Experimental Study on Frozen Durability and Damage Model of Air-entraining Recycled Concrete

The frozen durability cycle test was carried out on C30 recycled concrete and C30 air-entraining recycled concrete with the content of recycled coarse aggregate of 0%, 25%, 50%, 75% and 100%, so as to obtain the variation rules of quality loss rate and dynamic elastic modulus in the freeze-thaw cycle. Based on the Aas-jakobsen damage model, the relative difference of the actual stress ratio was defined as the damage variable, and the relative dynamic elastic modulus was used as the damage variable to fit the antifreeze performance parameter, and the freeze-thaw damage relationship was verified. The results show that: The frost resistance of recycled concrete with 50% admixture is similar to that of ordinary recycled concrete, and it is better than that of other admixtures. At the same time, adding air entrainment agent to the recycled concrete can improve the frost resistance. The calculated and measured values of the damage model agree with each other, which verifies the rationality of the damage model