低温硅灰-硅酸盐水泥复合胶凝体系力学性能及微观结构

目的研究不同温度体系时不同的硅灰掺量对复合胶凝体系的力学性能及微观结构的影响．方法在低温条件下，将体积分数为0、2％、5％、8％、10％的硅灰掺入到硅酸盐水泥中，测试水泥砂浆的抗压、抗折强度，进行SEM扫描电镜分析．结果随着硅灰掺入量的增加，复合胶凝体系的力学性能呈现先增加后降低的趋势，结构趋于密实；当硅灰的掺量达到8％时，复合胶凝体系的14d抗压、抗折强度达到最大值．结论低温环境影响了复合胶凝体系力学性能的发展，硅灰的加入促进了复合胶凝体系的水化，改善了水泥石的微观结构．

Mechanical Properties and Microstructure of Cementitious System with Portland Cement and Silica Fume at Low Temperature

At various temperatures, influence of different mixing amount of silica fume on mechanical proper- ties and microstructure of composite cementitious system is studied. On condition of low temperature, differ- ent mixing amount（0,2% ,5% ,8%, 10% ）of silica fume is added into Portland cement after which the com- pressive and flexure strength of the cementitious mortar is tested and the scanning electron microscope （SEM） analysis is done. With the increase of mixing amount of silica fume, mechanical properties of the composite cementitious system are improved at the beginning and then tend to depress, while its structure gets dense all the time. When the mixing amount of silica fume reaches 8%, 14d compressive and flexure strength of the composite cementitious system reach a maximum. As a result, low temperature can influence the development of mechanical properties of composite cementitious system,but adding silica fume can pro- mote hydration of the composite cementitious system and strengthen microstructure of set cement.