硅灰粒径分布对混凝土微观结构及其低温抗压强度的影响

Effects of particle size distribution of silica fume on pore structure and compressive strength of concrete at low temperature

在不改变混凝土配合比的前提下,将研磨制备的不同粒径分布的硅灰掺入到混凝土中;在低温环境下对硅灰混凝土进行不同龄期的养护后研究其抗压强度以及孔隙特征、孔径分布等微观结构的变化。结果表明:在温度为-10℃、养护龄期为28 d的条件下,掺入比表面积为18.2 m^2/g硅灰的混凝土的抗压强度提高了35.89%,总孔隙率降低了3.1%,多害孔和有害孔占比分别降低了19.4%、44.1%,少害孔和无害孔占比分别提高了31.6%、46.4%,优化硅灰的粒径分布可以改善混凝土的微观结构的致密性,从而提高混凝土在低温环境下的抗压强度。

On the premise of not changing the mix ratio of concrete,silica fume with different particle size distribution prepared by grinding was mixed into concrete. The compressive strength,pore characteristics,pore size distribution and other microstructure changes of silica fume concrete were studied after curing at different ages at low temperature. The results show that under the conditions of-10 ℃ and 28 d curing age,the compressive strength of the concrete mixed with a specific surface area of 18. 2 m^2/g silica fume increases by 35. 89%,the total porosity decreases by 3. 1%,the proportion of much harmful and harmful holes decreases by 19. 4% and 44. 1% respectively,and the proportion of less harmful and harmless holes increases by 31. 6% and 46. 4% respectively. Therefore,optimizing the particle size distribution of silica fume can improve the compactness of concrete microstructure and improve the compressive strength of concrete under low temperature environment.