STRUCTURAL CONCRETE, cilt.1, sa.1, ss.1-19, 2024 (SCI-Expanded)
Geopolymer mortars, which cause less CO 2 emissions than concrete and itsraw material cement, are an innovative, environmentally friendly and sustain-able building material. Geopolymers are formed by activating silica and alu-mina materials with alkaline activators. In this study, a geopolymer mortarcontaining obsidian (OB), also known as volcanic glass, which is free, and sil-ica fume (SF), which is the waste material of the silicon and ferrosilicon indus-try, was investigated. The behavior of OB-based geopolymer mortars underdifferent curing times ranging from 2 to 120 h and different thermal treatmenttemperatures such as 90, 150, and 200C were examined. The effectiveness ofOB and SF on the physical features, compressive strength (CS), and micro-structural of the geopolymers were characterized. Results demonstrated thatthe peak CSs were acquired in 96 h at 90 and 150C heat treatment tempera-tures, while the highest CSs were acquired in 72 h for specimens subjected to200C heat treatment. Reduces in CSs were detected when the curing timeexceeded the ideal limit. OB-based geopolymer was found to be stable with SFand there was a linear relationship between SF substitution ratio and CS. Thedensity of the mortar pieces decreased with increasing thermal curing hours.Devolving on the thermal temperature and curing time, the microstructuresbecame more compact and microvoids and cracks decreased. It was observedthat SF substitution reduced the total pore size of the geopolymers and allowedthe pore structure size to be reduced. The results obtained from the study areexpected to encourage the utilize of industrial wastes and new binders in themanufacture of geopolymers.