Realisation of enhanced self-compacting geopolymer concrete using spent garnet as sand replacement

Garnets are a waste spin-off of surface treatment operations and thus remain a major environmental concern worldwide. The robust engineering properties of these waste garnets offer the opportunity to obtain efficient construction materials by way of their appropriate recycling. In this spirit, the authors evaluate the capacity of spent garnets as sand replacement for achieving self-compacting geopolymer concrete (SCGPC). Such SCGPC specimens are prepared using ground granulated blast-furnace slag (GGBFS) wherein the river sand is replaced by spent garnet at varying contents (0 to 100%) under constant liquid/binder (L/B) mass ratio of 0·4. Performance evaluations of the developed SCGPC samples are made using several tests, including durability, workability and flexural, compressive and splitting tensile strength conforming to the Efnarc standard. Test results reveal an enhancement in the workability of the proposed SCGPC specimen with the increase of spent garnet contents. Furthermore, other strengths are discerned to be lower compared to the control sample at all stages of replacement. It is established that the spent garnet is a prospective candidate for sand replacement up to 25% in terms of environmental friendliness, cost effectiveness and conservation of natural resources.