Mechanical and micro-structural aspects of admixture stabilized rock sludge dust

Abstract

The Rock Sludge Dust (RSD) is a by-product generated during the cutting and polishing of stone slabs obtained from rock blocks in the rock processing industry. Currently, only a minimal amount of RSD is being used, while larger quantities are being stored within the industrial vicinity. In its dry state, this fine sludge dust is susceptible to rising even under mild winds, causing severe health and environmental concerns. The previous attempts by a few researchers to utilize this industrial waste were confined to brick making, cement manufacturing and concrete making within the projected utilization of up to 20%; and even to that extent, the field performance and confirmatory studies are lacking. In this endeavor, an attempt is made to study the possible use of non-reactive RSD as a passive bulk material within the stabilized matrix using other materials such as locally available clay soil, lime, and pozzolan (fly ash). The present study revealed that the addition of 10% local clay soil to RSD could alter its dust texture to natural soil texture so that its handling and transportation become convenient without dust nuisance. Further, the addition of 5% lime and 10% fly ash could impart UCS values ranging from 3.20 MPa to 5.88 MPa, thus making it a suitable material for the construction of low-volume roads. The XRD and SEM analyses of the favorable mix combinations arrived at based on the tests on trial mixes indicate the formation of cementitious minerals and gels. These findings enable the concerned construction industry to utilize the non-reactive RSD for gainful purposes, alleviating environmental issues and making the approach sustainable and eco-friendly.