摘要
不同温度下粉煤灰、矿粉和硅灰对喷射混凝土水化行为及力学性能的影响规律尚不明确。本文通过XRD定量分析、热重分析和SEM测试等手段表征了不同温度和龄期下三种矿物掺合料对喷射混凝土水化行为的影响,并测试了砂浆抗压强度。结果表明,不同温度下,硅灰和矿粉能提高喷射混凝土早期和后期强度,粉煤灰不利于早期强度的发展,20℃时粉煤灰体系砂浆6 h抗压强度低于基准值。6 h和1 d龄期时,温度对试块抗压强度的影响非常显著,60℃时硅灰体系砂浆6 h抗压强度高达13.39 MPa;随着龄期增长,温度对试块强度的增强作用减弱。温度升高会激发矿物掺合料的火山灰效应,生成C-S-H凝胶填充内部孔隙,提高体系砂浆试块抗压强度。同一温度、龄期下,硅灰体系水化产物中C-S-H凝胶含量多,抗压强度最高。矿粉体系水化程度最高,抗压强度较高。粉煤灰体系中AFt含量最高,但C-S-H凝胶含量少,抗压强度最低。本文对特殊环境下矿物掺合料在喷射混凝土中的应用有指导作用。
The effects of fly ash,slag and silica fume on hydration behavior and mechanical properties of shotcrete at different temperatures are still unclear.The effects of three mineral admixtures on the hydration behavior of shotcrete at different temperatures and ages were characterized by XRD quantitative analysis,thermogravimetric analysis and SEM test,and the compressive strength of mortar was tested.The results show that silica fume and slag can improve the early and late strength of shotcrete at different temperatures,while fly ash is not conducive to the development of early strength.The 6 h compressive strength of fly ash mortar is lower than reference value at 20℃.At 6 h and 1 d ages,the effect of temperature on the compressive strength of test blocks is very significant,and the 6 h compressive strength of silica mortar at 60℃is as high as 13.39 MPa.With the increase of age,the strengthening effect of temperature on the strength of test block decreases.The increase of temperature stimulates the pozzolana effect of mineral admixture,generates C-S-H gel to fill the internal pores and improve the compressive strength of mortar test block.At the same temperature and age,the content of C-S-H gel in hydration products of silica fume system is high,resulting in the highest compressive strength.The slag system has the highest degree of hydration,resulting in higher compressive strength.Although AFt content of fly ash system is the highest,C-S-H gel content is low,resulting in the lowest compressive strength.This paper provides guidance for the application of mineral admixtures in shotcrete under special environment.
作者
原健
王琴
曾凡超
郭志翔
王宏维
YUAN Jian;WANG Qin;ZENG Fanchao;GUO Zhixiang;WANG Hongwei(Key Laboratory of Functional Materials for Building Structure and Environment Remediation,School of Civil and Transportation Engineering,Beijing University of Civil Engineering and Architecture,Beijing 100044,China;Shanxi Jiawei New Material Co.,Ltd.,Yuncheng 044200,China)
出处
《硅酸盐通报》
CAS
北大核心
2024年第2期407-417,共11页
Bulletin of the Chinese Ceramic Society
基金
国家自然科学基金(52278237)
运城市科技局揭榜挂帅项目
北京市学者基金(067)。
关键词
喷射混凝土
矿物掺合料
无碱速凝剂
温度
水化
shotcrete
mineral admixture
alkali-free accelerator
temperature
hydration
