Applicability of calcium carbide residues for the improvement of soft peaty clay

Abstract

Most of the constructions in Sri Lanka is to be carried out on soft peaty clay. The problems with the soft peaty clay are its high-water content, being extremely compressible and having very low shear capacity. Therefore, from an engineering point of view it is very important to improve the geotechnical properties of this weak soil. Among the methods of chemical stabilization, the most common method used in world is stabilization using cement. However, using cement in such large-scale projects is unbearable for a developing country like Sri Lanka. This study is to evaluate the suitability of Calcium carbide residues (CCR) as a binder to improve soft peaty clay. Number of samples were prepared by mixing CCR with different proportions having maximum of 20% binder in soil. Improvements achieved in strength of treated peat for short term and long term were assessed by conducting unconsolidated undrained triaxial tests at 28 days and 90 days respectively. The results have shown that when the CCR content is increased, shear strength is gradually decreased in both short-term and long-term curing. However, strength improvement due to CCR is higher in long-term curing. That will be economically beneficial in projects where stabilization of soil is done in larger scale.