Dynamic compressive properties of lightweight rubberized geopolymer concrete

Abstract

With the aim of incorporating sustainability into the ordinary concrete production, the construction industry has been utilizing solid waste materials to replace raw ingredients such as natural aggregates and cement. A practical solution to this is the cement-free geopolymer concrete in which alkali activators have chemical reactions with pozzolanic material and cementitious material, such as fly ash, silica fume, and blast furnace slag. The increasing landfill of waste tyre rubber has also resulted in environmental issues. One of the potential utilizations for waste rubber is to partially substitute the natural aggregates of geopolymer concrete. This study experimentally investigated the effect of different proportions of crumb rubber partially replacing both coarse and fine aggregates (i.e. 0%, 15%, and 30% by volume) on the dynamic characteristics of geopolymer concrete. The dynamic compressive properties of geopolymer concrete incorporated with crumb rubber (RuGPC) were studied by Split Hopkinson Pressure Bar (SHPB) tests with strain rate up to 136 s−1. The experimental results showed rubberized geopolymer concrete consistently exhibited better impact resistance as compared with normal geopolymer concrete, as evidenced by crack initiation and propagation, failure mode, and normalized energy absorption. The dynamic compressive strength of rubberized geopolymer concrete showed prominent sensitivity to strain rate and the sensitivity to strain rate increased with the rubber content. Finally, empirical formulae to predict dynamic increase factors (DIFs) of geopolymer concrete compressive strength with various levels of rubber replacement were derived.