加密硅灰在净浆和混凝土中的作用对比

Comparison of the roles of densified silica fume in paste and concrete

为了探讨加密硅灰在净浆和混凝土中的作用效果差异,设置了4种不同的加密硅灰掺量(0%、6%、12%、18%),研究加密硅灰对混凝土抗压强度、净浆抗压强度、孔隙特征和微观形貌的影响。研究结果表明:加密硅灰在净浆硬化浆体中的团簇作用明显,部分硅灰团簇内有明显裂缝,使净浆总孔隙率增大,造成净浆抗压强度降低;加密硅灰在混凝土体系中,由于骨料的磨擦作用,团簇较少,能够相对较好的分散,且硅灰的火山灰反应起到改善界面过渡区的作用,使混凝土抗压强度提高。

This study investigates the differences of the roles of densified silica fume in paste and concrete. Four silica fume adding amount were set： 0% ,6% , 12% and 18%. The influences of densified silica fume on the compressive strength of concrete and paste, and the pore structure and micro-morphology of paste were measured. The results show that there are many densified silica fume clusters in the hardened paste and there are even large cracks in some clusters, which increases the total porosity and reduces thecompressive strength of hardened paste. The attrition of aggregates during mixing makes densified silica fume better dispersed, and the pozzolanic reaction of silica fume improves the interracial transition zone, which lead to the increase of the compressive strength of concrete.