橡胶集料对混凝土抗冻性的影响

Effects of Rubber Aggregate on the Frost Resistance of Concrete

取两种不同粒径、四种不同掺量的橡胶代替等体积的细骨料砂制作橡胶混凝土试件,对其进行快冻法试验,研究橡胶集料混凝土在冻融循环作用下的耐久性.研究表明,随着橡胶掺量的不断增加,抗压强度和动弹性模量都会不断下降,但掺入橡胶能改善混凝土的抗冻性,橡胶粉比橡胶颗粒的效果好,掺入5%~10%的粒径≤0.27mm橡胶粉对混凝土的抗冻性能有明显改善作用.不过,掺入过多的橡胶则会降低其抗冻性.结果表明,运用无损检测的动弹性模量能很好地对橡胶混凝土的抗冻性作出正确评价.

Rubber concrete specimens, made by mixing rubber with two types of grain size and four contents to replace the fine aggregate in the Portland cement concrete, were used for quick freeze-thaw test. This study focused on the durability of rubber concrete under freeze-thawing cycle conditions, which confirms that the concrete strength and dynamic elasticity modulus decrease with the increasing rubber content. It is also found that, appropriate proportion of fine aggregate replaced by the discarded tires powder and grain could improve concrete durability under freeze-thaw actions and the mixture of rubber powder show better performance than that of rubber grain. Especially, mixing 5 % --10 % rubber powder into concrete can improve resistance to frost obviously, however, the adverse effect for too much rubber is also found. The results reveal that dynamic elasticity modulus can make an accurate assessment to frost resistance of rubber concrete according to non-destructive testing.