Development of Lightweight Aggregate Concrete with Locally Available Lightweight Materials

Alternative building materials are a significant aspect of the construction industry due to the over-exploitation of natural resources and the cost increment of raw materials. Therefore, past studies have focused on the development of lightweight aggregate concrete (LWAC) using various lightweight materials such as bottom ash, waste Calicut tiles, coconut shells and fibers, wood waste, recycled plastic, expanded polystyrene, and sludge. However, most past research on the development of lightweight aggregate concrete focused on directly replacing locally accessible lightweight materials. Furthermore, no more studies were done on the development of lightweight aggregate concrete by using converted lightweight aggregates from locally accessible lightweight materials. Therefore, this study was focused on developing lightweight aggregate concrete mix designs with locally available lightweight materials. Sludge derived from the water treatment plant, Expanded Polystyrene (EPS), and waste Calicut tiles were used as lightweight materials to develop lightweight aggregate concrete. Sludge obtained from water treatment plants was fired at 1050 °C for 6–8 h to convert it into lightweight aggregate while waste Calicut tiles were mechanically crushed to convert it into lightweight aggregate. Furthermore, mineral admixtures such as fly ash and silica fume were added to improve lightweight concrete’s fresh and hardened properties. It is observed that the unit weight of the developed lightweight aggregate concrete was in the range of 1130–2280 kg m−3. The 28-day compressive strength of concrete ranges from 3.9 to 44.8 MPa for sludge and EPS-based lightweight concrete respectively. Due to the lower unit weight and compressive strength, sludge-based concrete mix designs can be used for non-loadbearing structural elements in multi-story, which reduces the total deadweight of the structure.