Adding granite polishing waste as sand replacement to improve packing density, rheology, strength and impermeability of mortar

Abstract

Reducing waste disposal from stoneware industry and reducing use of sand in construction industry are both important for sustainable development. One strategy to tackle both problems is to utilize the waste from stoneware factories to replace the sand in mortar/concrete production. To study the possible use of granite polishing waste (GPW) as sand replacement, a research programme was launched to test the flowability, cohesiveness, adhesiveness, strength and sorptivity of mortar mixes made with various GPW contents and water/cement ratios. To investigate the fundamental causes of the effects exerted by the GPW, the packing density, water film thickness and porosity of the mortar mixes were also measured. The results showed that adding a suitable amount of GPW as sand replacement would, apart from reducing waste disposal and sand consumption, also improve mortar performance by filling the voids between sand particles to decrease the voids ratio and porosity and increase the packing density and water film thickness. Overall, within the ranges of mix parameters covered in this study, the addition of GPW to replace 15% to 20% sand by volume would increase the strength by 31.2% to 70.9% and improve the rheology and impermeability.