Valorization of Industrial and Agro By-products into a Biobased Sustainable Controlled Low Strength Material

This study explored the development of biobased sustainable controlled low strength materials (CLSM) by use of an agro by-product i.e., unprocessed rice husk ash and two industrial by-products i.e., spent foundry sand and cement kiln dust. The proposed CLSM mixes comprised of spent foundry sand and unprocessed rice husk ash in 50:50 ratio (w/w) in complete replacement of the natural sand and cement kiln dust progressively replacing ordinary Portland cement at five levels with difference of 25% between 0 and 100%. The binder to aggregate ratio as 1:3 and a flowability at around 200 mm was maintained for the mixes. Various characteristics of the CLSM in fresh and hardened state were evaluated along with analysis of ecological parameters like embodied energy, embodied carbon dioxide and the environmental aspect of leachate toxicity. The results established the development of an environmentally safe, excavatable CLSM entirely by use of spent foundry sand, rice husk ash and cement kiln dust. Mix with 75% CKD met almost all desirable practical requirements of CLSM. Use of by-products proved eco-friendly by affecting a reduction of embodied energy and embodied carbon dioxide. CLSM made by using these by-products can prove to be an innovative biobased sustainable construction material facilitating valorization of agro based and industrial by-products along with providing an effective infrastructural solution for their large-scale disposal.