硅灰和粉煤灰取代率对橡胶混凝土强度影响试验研究

EXPERIMENTAL STUDY ON THE INFLUENCE OF REPLACEMENT RATES OF THE SILICA FUME AND FLY ASH ON THE STRENGTH OF RUBBERIZED CONCRETE

文中以橡胶混凝土为研究对象,分别考虑10%、20%、30%三种橡胶颗粒体积代替等体积细骨料,同时考虑不同水泥取代率的硅灰和粉煤灰的影响,研究其立方体抗压强度、抗折强度、折压比的变化规律,并揭示破坏机理。研究表明,与普通混凝土相比,橡胶混凝土破坏时表现为明显的延性破坏,随橡胶取代率增加,橡胶混凝土的抗压和抗折强度均有不同程度的下降,其中抗压强度的下降程度更大,而折压比随橡胶掺量逐渐增大,韧性有明显的改善;利用硅灰可以使橡胶混凝土的强度得到一定程度的提高,当硅灰的取代率为10%时,抗折强度和抗压强度分别提高了16%、13%,此后若继续增大硅灰取代率,强度则无明显变化,而粉煤灰对橡胶混凝土的增强效果并不明显。

In this paper, rubberized concrete is taken as the research objects. We substitute three kinds of crumb rubber for fine aggregates at the same volume and their replacement rates are respectively 10%,20%,30%. At the same time, we explore how the silica fume and fly ash which are substituted for the cement at the different replacement rates affect the mechanical properties of rubberized concretes, including the compressive strength, flexural strength and the ratio of the compressive strength to flexural strength and reveal the failure mechanism. The results show that it exhibits a ductile failure obviously compared to the normal concrete when the rubberized concrete yields. With the increase of the crumb rubber replacement rate, both of its compressive strength and flexural strength decrease with varying degrees, and the compressive has a bigger reduction. However, the ratio of the compressive strength to flexural strength increases gradually and the toughness of concretes is remarkably improved. What's more, the strength of rubberized concrete can be improved by the silica fume. When the silica fume replacement rate is 10%, the flexural strength and compressive strength increase by 16% and 13%, respectively. After that, if the silica fume replacement rate continues to increase, the strength does not have the obvious change, and the influence of fly ash on the rubberized concrete is not obvious.