Influence of geopolymer aggregates on microstructural and strength characteristics of OPC concrete

摘要

This paper investigated the physical and microstructural properties of a manufactured fly ash-GGBFS-based geopolymer aggregates. The analysis on geopolymer aggregate included specific gravity, water absorption, crushing value, impact value, attrition, loss angles abrasion, and angularity index. Besides, scanning electron microscopy (SEM) was done to diagnose the microstructure of geopolymer aggregates. In contrast, the compressive strength of geopolymer aggregate-based ordinary Portland cement (OPC) concrete was studied. Besides, the microstructure and the pore structure development of geopolymer aggregate-based concrete at the interfacial transition zone (ITZ) were examined through SEM. In this paper, three types of geopolymer aggregates are prepared by replacing 0, 10, and 20% of fly ash with GGBFS cured under an oven (at 60 degrees for 12 h) and ambient conditions. The experimental data showed that the dry density of manufactured geopolymer aggregate concrete was less than that of natural aggregate-based concrete; it is about 1000 kg/m(3) for geopolymer aggregate. However, concrete prepared geopolymer aggregates (80% fly ash and 20% GGBFS) showed higher resistance among all the tests and giving similar results at ambient and oven curing.