Rice husk ash with high carbon content proves favourable for soil stabilization

Rice husk ash is a promising pozzolanic material produced from rice husk burning and has significant potential a sustainable replacement for cement in construction and ground improvement applications. In this study the effect of burning conditions on the ash reactivity and its potential for soil stabilization applications have been investigated Three different burning procedures were applied: 1) controlled burning at 500°C followed by rapid cooling, which was according to literature considered to produce the highest reactivity, 2) burning at 700°C with slow heating and cooling, which was expected to result in lower reactivity due to die crystallization of the silica and 3) uncontrolled burning in open-fire. The third procedure unexpectedly produced the most reactive and still some carbon. Adding rice husk ash and lime to wet clay significantly increased the strength of the clay after curing. Again, the carbon-containing ash showed the largest strength improvement Incomplete combustion seems therefore preferable for soil stabilization applications with rice husk ash