废瓷砖再生骨料与水泥石的界面特征

摘要

Ceramic tile recycled aggregate concrete(CRAC) was prepared by using waste ceramic tile as recycled aggregate instead of natural coarse aggregate(NCA).Strength and work performance of CRAC,interfacial bond strength between recycled aggregate and cement paste were determined.Hydration degree and microstructure of interfacial transition zone(ITZ) were studied in terms of chemically combined water content by SEM and BET tests.Results show that ceramic tile recycled aggregate(CRA) has higher porosity,smaller density,and higher strength compared with NCA.Under the same mix proportion,work ability and mechanical strength of CRAC are better than those of natural coarse aggregate (NCAC).Under condition of the same water-cement ratio and curing age,interfacial bond strength of CRA-cement paste is higher than that of NCA-cement paste.Compared to NCA-cement paste ITZ,hydration product of CRA-cement paste ITZ is much more,porosity of it is less and microstructure of it is denser.%以废瓷砖再生骨料(CRA) 100％替代原生碎石骨料(NCA),制备了废瓷砖再生骨料混凝土(CRAC),测试了其工作性及力学强度.采用化学结合水法、扫描电子显微镜(SEM)及比表面积测试法(BET)等,研究了废瓷砖再生骨料-水泥石界面黏结强度、水化程度及显微结构,探讨其界面特征,并将其与原生碎石骨料(NCA)-水泥石界面相比较.结果表明:与原生碎石骨料相比,废瓷砖再生骨料具有表观密度较小、压碎指标较高及吸水率较大等特点;在相同配合比条件下,废瓷砖再生骨料混凝土具有更好的工作性和力学强度;在相同水灰比、相同龄期条件下,废瓷砖再生骨料-水泥石界面黏结强度较高,其界面区生成的水化产物较多、孔隙率更低、显微结构更加致密.