Performance of wood bottom ash in cement-based applications and comparison with other selected ashes: Overview

Wood bottom ash (WBA) is a type of wood waste ash produced as a by-product from the incineration or combustion from wood-fired power plants, pulp and paper and wood-burning industrial facilities. It is the fraternal twin of the most common and popular fly-ash which is obtained from the same process. Most of the WBA produced are disposed in landfills while few quantities of it are being used as supplementary cementitious materials (SCM) because of their pozzolanic activities. Several studies have been published to evaluate generally the use of wood waste and fly ashes as construction materials but the use of WBA as an entity has not found prominent attention when compared with the former. This review gives a comprehensive report of the factors determining the performance of WBA as cementitious material, physio-chemical characteristics of the ash, performance assessment of WBA on some cementitious properties, occupational hazard associated with WBA when used as a construction material and comparison with wood fly-ash and lastly the comparison of engineering properties between WBA and other major ashes used as SCMs' for construction purposes. The other ashes considered and compared with WBA were wood fly ash (FA1), sugarcane bagasse ash (SB1), rice husk ash (RH1), palm-oil ash (PO1), coal fly ash (CA1), coal bottom ash (CA2), municipal solid waste ash (SW1), bamboo leaf ash (BL) and waste paper sludge ash (WP). The findings revealed that inclusion of WBA at an optimum level in cement-based materials is valuable to sustainable development as well as for waste management.