摘要
本文选用S95级和S140级矿粉,以及硅灰和纳米二氧化硅分散液这2种活性硅质材料,分别代替部分水泥制备不同胶凝材料体系,通过测试喷射混凝土的凝结时间和力学性能,运用定量XRD、TG、SEM等测试手段,分别对比了掺入2种矿粉和2种活性硅质材料的喷射混凝土宏观性能及微观结构的差异。结果表明:掺入S95级矿粉和S140级矿粉后,均会延长喷射混凝土的凝结时间,但是活性更高的S140级矿粉缓凝效果更弱;纳米二氧化硅分散液不会出现硅灰需水量大,凝结时间过快的现象。此外,2种矿粉和2种活性硅质材料均能提高体系的抗压强度,其中,S140级矿粉体系>S95级矿粉体系,硅灰体系>纳米二氧化硅分散液体系,但是极低掺量的纳米二氧化硅分散液可以接近硅灰的使用效果,且喷射混凝土强度越高,其对应的C-S-H凝胶相含量越高,微观形貌中晶胶界面更少,结构也更为致密,可为喷射混凝土的胶凝材料选择提供指导。
In this paper,two kinds of slag powders and two kinds of active silicon-based substances are used to replace part of cement to prepare different cementitious material systems.Through testing methods such as setting time,mechanical properties test,quantitative XRD,TG,SEM,the differences in macroscopic properties and microstructure of shotcrete with two kinds of slag powders systems and two kinds of active silicon-based substances systems are compared respectively.The results show that both kinds of slag powders will delay the setting time,but the higher activity of S140 slag powder will weaken some of the influence;nano-silica dispersion do not have the phenomenon of large water demand and fast setting time of silica fume.Two kinds of slag powders and two kinds of active silicon-based substances can improve the compressive strength of the system,among which S140 slag powder>S95 slag powder,silica fume>nano-silica dispersion,but the very low content of nano-silica dispersion can be close to the effect of silica fume.The higher the strength,the more the C-S-H gel phase content in the corresponding system,and the denser the structure when the crystal-gel interface in the microstructure of the system is less.This study provides some guidance for the selection of cementitious materials for sprayed concrete.
出处
《混凝土世界》
2025年第2期14-22,共9页
China Concrete
基金
运城市科技局揭榜挂帅项目(Z22085)
北京建筑大学研究生创新项目(02081024003)。
关键词
矿粉
活性硅质材料
水化产物
微观结构
Slag powder
active silicon-based substance
hydration products
microstructure
