Use of Waste Ash from Agricultural by-Products in Concrete Work

Abstract

This paper presents a study on the strength and porosity of mortars made with binary blends of ordinary Portland cement type I (OPC) sand and ground rice husk ash (RHA) or ground palm oil fuel ash (POA). The mortar mixtures were made with Portland cement Type I containing 0-40% RHA and POA. The water to binder ratio was kept constant at 0.5 and the flow of mortar was maintained at 110 +/- 5% with the aid of superplasticizer (SP). X-ray diffraction (XRD) and scanning electron microscopy (SEM) were used on materials. Compressive strength and porosity of the mortar were determined. The XRD pattern confirmed that POA and RHA were mainly amorphous silica. The use of RHA and POA produced waste ash with relatively high strength. The porosity of mortar containing RHA and POA decreased with the low replacement level of up to 20% of pozzolanic but increased with the 40% replacement level. RHA and POA have a high potential to be used as a good pozzolanic material in concrete work.