A ternary optimization of alkali-activated cement mortars incorporating glass powder, slag and calcium aluminate cement

Abstract

This paper introduces the use of a simplex-centroid design method, together with a ternary contour diagram, to evaluate the effect of blending different proportions of soda lime glass powder (GP), ground granulated blast furnace slag (GGBS) and calcium aluminate cement (CAC) on the compressive strength, alkali-silica reaction (ASR) expansion, drying shrinkage and high temperature resistance of alkali-activated cement (AAC) mortars prepared with the use of crushed glass cullet (GC) as aggregates. The relationship between performance of the geopolymer and precursor composition was established. It was found the ASR expansion increased with the increase of GP content and the addition of CAC as the replacement of GGBS could significantly reduce the ASR expansion. The drying shrinkage increased with the increase of GGBS contents. The residual strength coefficient of the mortars after high temperature exposure increased with the increase of CAC content and could be higher than 100%. And the strength coefficient increased with the increase of GP content resulted from its partial melting at the high temperature. It was found that the GP content should be in the range of 77–90%, the GGBS content should be lower than 5% and the CAC content should be higher than 10% to achieve acceptable ASR expansion and drying shrinkage.