Sustainable incorporation of waste granite dust as partial replacement of sand in autoclave aerated concrete

摘要

Granite dust produced in the marble processing industry is fatal to human health and uneconomical to dispose because of limited disposal sites, especially in the urban regions. It contaminates the air and contributes to the particulate matter, which causes several respiratory and cardiovascular diseases. Granite dust could valuably be incorporated as partial sand replacement in autoclave aerated concrete (AAC), thereby reducing health and environmental hazards, and controlling sand depletion by fulfilling sand demand. The recent research explores the potential feasibility of adding waste granite dust (WGD) into AAC by replacing 5, 10, 15 and 20% fractional weight of sand. Micro-forensic investigations revealed these granite dust platelets as angular and flaky in shape, rough and abrasive in texture alongside amorphous crystallography with an average grain size of 15.08 mm. In conjunction with AAC, the addition of WGD effectively modified the physical, mechanical, microstructural and thermal behavior of concrete mixtures alongside their resistance to aggressive acids. The maximum increase in the compressive strength was observed to be 42% for the mix containing 20% replacement of fine aggregates by WGD, which may be attributed to the relatively refined microstructure, bearing tobermorite formation and pozzolanic actions, as evidenced in the scanning electron micrographs and thermograms. It further increased their resistance to the strong acids, which was 54% and 32% higher than that of the reference mix, when exposed to 5% solution of sulphuric acid (H2SO4) and hydrochloric acid (HCl), respectively. Conclusively, the use of WGD as partial replacement of sand provided an eco-friendly and sustainable option for AAC. (C) 2020 Elsevier Ltd. All rights reserved.