摘要
用交流阻抗、差热分析等技术研究了不同矿物掺合料组成和水胶比下,UHPC基体的组成与微观孔结构关系。结果表明,矿粉与硅灰的掺入可以极大地改善基体的孔隙结构。在粉煤灰和矿粉最密堆积下,UHPC基体的体积电阻随着硅灰掺量的增加而增加,当硅灰掺量大于20%,低水胶比时,基体的体积电阻达到相对最大值。当水胶比大于0.18时,UHPC基体的体积电阻随着水胶比的增大而减小。通过孔隙吸水率研究表明,在热养护2 d条件下,UHPC基体的孔隙吸水率总体上随着硅灰掺量的减少以及水胶比的增大而增加,在水胶比0.22以下孔隙结构可能开始不连通。差热分析的研究表明,硅灰的掺入降低了Ca(OH)_2含量,增加了C-S-H凝胶含量,说明硅灰通过发生火山灰反应改善UHPC基体的孔隙结构,在掺量大于20%、水胶比相对较低的情况下连通孔隙最少,达到最优孔隙结构。
The composition and microstructure of UHPC matrix were studied by means of AC impedance and differential thermal analysis. The results show that the pore structure of the matrix can be greatly improved by the incorporation of mineral powder and silica fume. The bulk resistance of the UHPC matrix increases with the increase of the content of silica fume,and the bulk resistance of the matrix reaches the maximum when the content of silica fume is greater than 20% and the low water to binder ratio. When the water binder ratio is greater than 0. 18,the volume resistivity of the UHPC matrix decreases with the increase of the water binder ratio. The pore water absorption studies show that in the heat curing condition of 2 d,pore water absorption rate of overall UHPC matrix with silica fume and reduce the water cement ratio increases,the pore structure may start not connected when the water cement ratio below 0. 22.Studies on the differential thermal analysis showed that silica fume decreased the Ca（OH）2 and increased the C-S-H content,pore structure description of silica fume by reaction of UHPC matrix to improve the volcano ash,the content is more than 20%,the water cement ratio is relatively low in the absence of connected pores at least,to achieve optimal pore structure.
出处
《硅酸盐通报》
CAS
CSCD
北大核心
2017年第12期4104-4111,共8页
Bulletin of the Chinese Ceramic Society
基金
国家自然科学基金(U1305245)
