Effects Of Rockdust As A Soil Stabilizing Agent On Poor Subgrade Soil

Abstract

Pavement failures are usually associated with the lateral displacement of subgrade as a result of pavement absorbing water and excessive deflection and differential settlement of material underneath the pavement. The aim of the research is to study the effect of the additives (rockdust) on the stability and the increase of bearing capacity of selected soils in Sabah. The physical, chemical and engineering properties of soil were studied, and the soils were treated with additives (rockdust) for the purpose of stabilising the native soil. The stabilisation of soil is carried out by addition of Rock dust to soils in the range of 0 to 85% by the percentage increase of 5%,10%, and 15 % respectively. The Results showed that the gradation of soil is narrow from the particle size analysis. Plasticity index (P.I.) and Liquid limit (L.L), and plastic limit (P.L.) were decreased with the addition of Rock dust. It was concluded that the value of the Maximum dry density increased with the addition of Rock dust, and the highest value was obtained when adding 10%  Rock dust, and beyond 10%, it shows a decrease in their content. It was found that the value of cohesion c decreased,  the angle of internal friction and the California  bearing ratio(C.B.R) was improved with the addition of Rock dust. The study showed that the best stabilizer for the case study is the Rock dust  and the optimum dose is 10 %.