Fine crushed aggregate as partial replacement of natural sand in mortars

Abstract

Abstract: In many countries of the world, there is an increasing unbalance between the demand for concrete aggregates and the available geological sources of aggregates. Therefore, significant research efforts have been made in order to develop sustainable solutions for concrete Industry. Quarry dust is a by-product and is a type of fine crushed aggregate (FCA) that needs to be disposed in a safe and environmentally-friendly way. The use of different types of FCA as replacement of natural sand has been extensively studied and is recognised by the Green Building Council of Australia. However, there is a high variability in the properties of FCA and their usage in concrete production is still limited. This paper presents a study on the properties of quarry dusts sourced from three different types of rocks in Western Australia and their effects on the voids content, flow and compressive strength of mortar mixtures. A series of experiments were conducted increasing the proportion of FCA in steps of 20% replacing natural sand. Flow of fresh mortar increased with the increase of two types of quarry dusts up to 60% replacement of natural sand and then declined with further increase. Compressive strength of mortar specimens increased with the increase of all three types of quarry dust up to 60% and then declined with further increase. Thus, it was found that up to 40 - 60% replacement of natural sand had positive effect on the performance of mortar mixtures.