Development of Lightweight Aggregate Concrete and Autoclaved Aerated Concrete using Indigenous Materials

Abstract

In this study, we used local resources to construct eco-friendly and thermally efficient lightweight concretes with a variety of stoichiometries. Three types of lightweight aggregates expanded shale, expanded slate and expanded clay were selected to achieve the goals of structural lightweight aggregate concrete (LWAC). Cellular and porous concrete in the form of Autoclaved Aerated Concrete (AAC) with fly ash as sand replacement was developed for non-structural units. Furthermore 5, 10, 15 and 20% of sawdust was replaced with fly ash in AAC to study the enhanced properties. Test results indicates that the hardened density of lightweight aggregate concrete reduces 23% as compare with normal-weight aggregate concrete (NWAC). Similarly, the compressive strength of lightweight aggregate concrete using expanded shale fall in the range of structural compressive strength in accordance with ACI 213. The thermal efficiency of LWAC using expanded shale is 70% enhanced as compare to NWAC. The hardened density of AAC reduces to about 68% in compare with NWAC. Similarly, the compressive strength of AAC fall in the range of non-structure concrete strength in accordance with ACI 213. The thermal efficiency improves up-to 66%. The incorporation of 25% wood waste in AAC also shows good thermal efficiency. Conclusively, the recipes for lightweight structure and non-concretes developed and the utilization of fly ash and wood waste is a useful source of raw materials for the building industry; an environmentally responsible solution for the disposal of fly ash and sawdust would contribute to the conservation of natural aggregate reservoirs.