高强硅粉混凝土抗冻性及气泡结构的试验研究

Freeze thaw resistance and air-void characteristics of high strength concrete with silica fume

本文对不掺硅粉,掺10％,15％硅粉混凝土的坍落度、含气量、抗压强度、冻融循环以及硬化混凝土气泡结构进行了试验与测试.试验成果表明:混凝土掺硅粉后,坍落度和含气量明显降低,抗压强度明显提高;当水胶比为0.3或小于0.3时,非引气硅粉混凝土可以经受300次快速冻融循环试验,而水胶比为0.32或大于0.32的硅粉混凝土则需掺引气型外加剂以保证其抗冻耐久性;在相同含气量的情况下,掺硅粉比不掺硅粉混凝土,改善了气泡结构性质.本文给用于修补工程中的高强硅粉混凝土的抗冻能力评定提供了试验依据.

In this paper, the slump, air content, compressive strength, freeze-thaw resistance and air-void characteristics of concrete without and with 10, 15% silica fume are presented. The test results indicate that the use of silica fume in concrete can obviously reduce slump and air content, and increase compressive strength. When water-cementitious ratio [water/ (cement+silica fume)] is 0.30 or less, non-air entrained silica fume concrete is frost resistant and can undergo 300 fast freeze-thaw cycles in accordance with ASTM C666. But when it is 0.32 or greater, an air entraining agent is needed to ensure the freeze-thaw resistance of silica fume concrete. Furthermore, under the condition of the same air content, air-void characteristics of silica fume concrete are improved, as compared with conventional concrete.