PRODUCTION AND UTILIZATION OF ACTIVE RICE HUSK ASH AS A SUBSTITUTE FOR CEMENT.

Abstract

Factors affecting the activity of rice husk ash (RHA) were examined using a specially designed muffle furnace and possibility of producing active RHA on a mass scale was sought. It is concluded that inherent activity of RHA is dependent on the cooling rate of resulted hot ash in addition to the previously reported factors such as burning temperature and burning time of rice husks and air supply during the burning. Rapid cooling is required for the production of more active RHA. RHA of good activity can be obtained by burning rice husks at 400 degree C for 4 hrs or more under enough air supply condition and cooling the resulted ash rapidly. When RHA grains of good activity are ground to a proper extent, as high as 70% of cement can be replaced by the RHA without impairing the strength of mortar at both 3 days and 28 days.