硅灰及矿渣粉对大掺量粉煤灰砂浆力学性能的影响及机理研究
Effects of Silica Fume and GGBS on Mechanical Properties of High Volume Fly Ash Mortar and Its Mechanism
刘扬 1王家理 2罗冬 2袁和平 2鲁乃唯 1王柏文2
作者信息
- 1. 长沙理工大学土木工程学院,长沙 410114
- 2. 长沙理工大学土木工程学院,长沙 410114;长沙理工大学桥梁工程安全控制教育部重点实验室,长沙 410114
- 折叠
摘要
以硅灰和矿渣粉(GGBS)为辅助胶凝材料,使用聚羧酸高性能减水剂,分别研究了硅灰和GGBS对大掺量粉煤灰砂浆抗压强度的影响.通过压汞测试(MIP)、扫描电子显微镜(SEM)以及X射线衍射(XRD)等方法对制备试件的孔结构、微观产物、物相组成进行分析,得到了硅灰和GGBS影响大掺量粉煤灰砂浆强度的机理.结果表明:单掺硅灰的大掺量粉煤灰砂浆的抗压强度随着硅灰含量增加先增大后减小,单掺GGBS的规律与硅灰类似;复掺硅灰和矿渣时,砂浆的强度较其他同龄期组均有一定的提高,二者表现出良好的协同作用;无论是单掺还是复掺,硅灰和GGBS都对大掺量粉煤灰砂浆强度有良好的提升作用.砂浆试件总孔隙率和大孔占比与抗压强度总体呈负相关,强度越高的砂浆试件微观结构越致密,但相比于总孔隙率,毛细孔和大孔占比表现出与抗压强度更好的相关性.当硅灰和GGBS质量分数分别为8％和6％时,砂浆28 d强度最大,为88.05 MPa.
Abstract
Using silica fume and ground granulated blast furnace slag(GGBS)as auxiliary cementitious materials and polyhydroxylic acid high-performance water reducer,the effects of silica fume and GGBS on the compressive strength of high volume fly ash mortar were studied.The pore structure,microstructure,and phase composition of prepared specimens were analyzed by mercury intrusion test(MIP),scanning electron microscope(SEM)and X-ray diffraction(XRD),and the mechanism of the effect of silica fume and GGBS on the strength of high volume fly ash mortar was obtained.The results show that with the increase of silica fume content,the compressive strength of high volume fly ash mortar mixed with silica fume increases first and then decreases.The law of GGBS mixing is similar to that of silica fume.Whether it is mixed alone or mixed,silica fume and GGBS are mixed together,the strength of mortar is improved compared with other age groups,and they show good synergy.Both silica fume and GGBS can improve the strength of high volume fly ash mortar.The total porosity and proportion of macropores of mortar specimens are negatively correlated with compressive strength.The higher the strength of mortar specimens is,the denser the microstructure is.But compared with the total porosity,the proportion of pores and macropores shows a better correlation with compressive strength.When the mass fraction of silica fume and GGBS is 8％and 6％respectively,the strength of mortar at 28 d is the highest,which is 88.05 MPa.
关键词
大掺量粉煤灰砂浆/硅灰/矿渣粉/抗压强度/微观结构Key words
high volume fly ash mortar/silica fume/GGBS/compressive strength/microstructure引用本文复制引用
出版年
2024
国家科技期刊平台
NSTL
万方数据