EFFECT OF GEOPOLYMER ON THE STRENGTH OF BLACK COTTON SOIL

Abstract

This paper presents in the improvement of problematic soils in a environmental friendly method. The present paper geopolymer to stabilize a soft soil. Geopolymer is an alkali activated solution prepared by combining sodium hydroxide(NaOH) with the sodium silicate solution(Na 2 SiO 3). The sodium hydroxide solution is prepared to 12M concentration and Na2SiO3/NaOH ratio of 2.5. The geopolymer increases the strength of the black cotton soil by geopolymerisation. The geopolymerisation process involves three separate but interrelated stages. During initial mixing the alkaline solution dissolves silicon and aluminium ions from the amorphous phases of the feedstock. In this solution, neighboring silicon or aluminium hydroxide molecules then undergo a condensation reaction, where adjacent hydroxyl ions from these near neighbors condense to form an oxygen bond linking the molecules and a free molecule of water. The application of mild heat causes these "monomers" and other silicon and aluminium hydroxide molecules to poly-condense or polymerise, to form rigid chains or nets of oxygen bonded tetrahedra. In the present study geopolymer is treated with the black cotton soil. The effect of geopolymer on strength characteristic of Black cotton soil have been studied for a curing period of 7days 15days and 28days. The compressive strength of black cotton soil increases with geopolymer dosage and curing.. The density of black cotton soil also increases with the increase in geopolymer. The test result indicates that geopolymer is very effective in stabilizing the soft soil. An attempt has been made to study the properties of soil treated with geopolymer