Experimental Study on the Suitability of Aluminium-Based Water Treatment Sludge as a Next Generation Sustainable Soil Replacement for Road Construction
25 Pages Posted: 20 Jan 2023
Abstract
Water treatment sludge is a by-product of the drinking water treatment process, and it has been considered as a waste for water authorities around the world. This study aims to investigate the reuse of aluminium-based water treatment sludge (AS) as a soil replacement in road construction which can improve sustainable waste management practices for positive environmental outcomes. Detailed physical and chemical characterisations were conducted with the water treatment sludge using Scanning Electron Microscope (SEM) and Inductively Coupled Plasma Optical Emission Spectroscopy (ICP–EOS). Sieve analysis and Atterberg limits as well as compaction characteristics were analysed for all the investigated materials. To evaluate the potential reuse of AS, a 50/50 mixture ratio of AS and clay (CL) was selected and tested for geotechnical engineering parameters. The results of these tests indicated the reuse of AS as a soil replacement with clay has positive outcomes for road construction. The AS and CL (CLAS) mixture demonstrated a better stress distribution ability compared to CL and AS independently. The addition of AS also had significant benefits to the stiffness and undrained strength of the mixture in the UCS tests. The strength of CLAS has increased by 50% on average compared to CL and CLAS and showed less cumulative strain than CL as well as improved CBR of the mixture from 0.95% with CL only to 1.92% which can be very beneficial in the construction of roads. In conclusion, there is potential for AS to be beneficially reused as a low-cost soil replacement.
Keywords: Sustainability, Recycling, water treatment sludge, Aluminium-based sludge, soil replacement
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