The Effect of Aggregate Content on the Expanded Lightweight Aggregate Geopolymer Concretes

摘要

The effect of total aggregate content (lightweight aggregate (LWA) and river sand) on fly ash lightweight aggregate geopolymer concretes (LWAGC) was studied in this paper. Expanded clay aggregate and sand were used as the coarse and fine aggregate, respectively, for making the lightweight aggregate geopolymer concretes. The proportion of LWA and river sand was fixed at 60% and 40%. The total aggregate content (LWA + river sand) relative with the geopolymer paste was varied at 50%, 55%, 60%, 65%, 70% and 75%. The geopolymer concretes were cured at room temperature (24 hours) and followed by 60 ~0 C (24 hours). The physical properties, compressive strength and microstructural analysis of the LWAGC were investigated. The results showed that the LWAGC with total aggregate content of 70% obtained the highest strength of 60.4 MPa. In addition, SEM microstructure reveals that the interfacial bond of the lightweight aggregate to the geopolymer paste. The well-bonded interfacial zone between LWA and geopolymer mortar was a characteristic of higher strength development of the concretes.