Study on properties of clay brick incorporating sludge of water treatment plant and agriculture waste

Abstract

Green building raw materials have become attractive alternatives for mitigating sustainability issues. Agricultural waste has been used as natural components in the production of alternative building products, and the use of burned clay bricks is a new waste disposal method. The main objective of the paper is to investigate the effects of agricultural waste (rice straw, sugarcane bagasse and wheat straw ashes) in clay bricks. This paper discusses the physical–mechanical properties and the micro-structure of clay bricks when incorporated with the sludge of water treatment plants (SWTP) to replace clay at a 50 % ratio. One mixture was prepared as a control mix without agriculture waste. Each group containing three mixes was used with 5 %, 10 % and 15 % by weight of SWTP content. The green bricks was air dried in sunlight for another 7 days and burnt at 900 °C, keeping them at the highest temperature for 3 h. Mechanical and physical properties of these bricks have been investigated. It was observed that clay bricks containing rice straw ash (RSA), sugar cane bagasse ash (SBA) and wheat straw ash (WSA) had lower compressive strength compared to non-RSA, SBA, and WSA clay bricks. The replacement 5–10 % of RSA, SBA and WSA by weight of SWTP into brick molding compound produces eco-friendly fired clay brick. Scanning electron microscopy (SEM) study confirms the porous microstructure of the brick specimens combining RSA, SBA and WSA resulting in lower bulk density resulting in lighter and more economical structures. Based on this analysis, it can be established that brick samples with lower doses of RSA, SBA and WSA (i.e. 5 % SWTP weight) will not only reduce the environmental pressure but will also lead to more efficient and economical development.