Pozzolanicity and Some Engineering Properties of Rice Husk Ash

Abstract

Rice Husk Ash (RHA) is an agro-waste material. It is found locally in abundance in Nigeria and many other parts of the world. Rice Husks pose environmental nuisance in developing countries. Efforts have been made to convert the material to economic usage. RHA is a form of pozzolan, a potential cementitious material. The material was mixed with 45 per cent slaked lime. The resultant product ‘cement’ has a specific gravity of 2.1. The initial and final setting times were found to be 4 ½ and 76 hours respectively. The pozzolanic Activity Index of the ash was determined. It was found to be highly pozzolanic. The average compressive strength was found to be 3.2 N/mm² (32.6 kg/cm²). The relationship between the compressive strength of its concrete and water-cement ratio was also studied. The optimum water-cement ratio was found to be 0.86.

Keywords: Rice Husk Ash, Pozzolan, Compressive strength, Setting times.