低水胶比和龄期影响下的硅粉水泥胶砂的强度研究

Experimental study on strength of cement mortar with silica fume under low water-binder ratio and age effects

为了更加有效地研究硅粉活性及硅粉对混凝土的强度影响,用相同质量分数的硅粉取代水泥配制水泥胶砂,在不同的水胶比、不同的硅粉取代量和不同龄期的综合条件下,对水泥胶砂的力学性能进行试验研究。结果表明：当水胶比分别为0.28、0.30和0.32时,与基准水泥胶砂相比,随着硅粉取代量的增加,水泥胶砂的3d抗压强度和抗折强度没有显著变化,但水泥胶砂的28d抗压强度和抗折强度却明显提高;过多的硅粉取代量不利于提高水泥胶砂的强度,且只降低水胶比并不能有效提高水泥胶砂的3d和28d强度。对于硅粉水泥胶砂的抗压强度和抗折强度,其中硅粉最优取代水泥的质量分数为9%~12%,且最优水胶比为0.30。

To more effectively study the activity of silica fume and its effects on the strength of concrete,the mechanical properties of cement mortar which obtained by substituting the same quantity of cement with silica fume were experimentally tested under different water-binder ratio,silica fume substitution,and age.The results indicate that compared with the standard concrete（reference sample）,no obvious improvement of 3dcompressive strength and flexural strength can be observed with the increase of silica fume substitution when the water-binder ratio is fixed to be 0.28,0.30,and 0.32,respectively,however,the 28 dcompressive strength and flexural strength of the cement mortar increase significantly.Too much silica fume substitution is not good for strength improvement of the cement mortar,and the 3dand 28 dstrength can also not be effectively enhanced by simply decreasing the water-binder ratio.For the cement,the best substitution amount of silica fume is 9%-12%,and the corresponding optimal water-binder ratio is 0.30.