Strength Characteristics of Clay Soil Admixed with Sand and Ca-based Stabiliser for Reduced Carbon Emissions

Abstract

Clay is exhibited as plastic and sticky when a large amount of water is added to it. A stabilisation trial was developed using mixes of clayey sand and chemical stabilisation for the soil. Clayey sand samples were prepared by mixing different sand-clay ratios (5S5C, 7S3C, 9S1C and 10S0C). Then, chemical stabilization was applied by adding Ca-based binding agent at different ratios of 0%, 2% and 4% of the total weight of the clayey sand samples. A series of Unconfined Compressive Strength (UCS) tests were performed on the clayey sand samples at four curing times (3, 7, 14 and 28 days). The materials utilised in this study were river sand, lateritic clay and Ca-based binding agent. The results showed that the UCS of clayey sand increases with stabiliser content and curing time. The UCS of 5S5C with 2% stabiliser was found to be increased significantly from 135.25 kPa to 977.41 kPa after 3 curing days. It complies with the Malaysia Public Works Department (MPWD) standards, i.e. the minimum UCS requirement of 800 kPa. In addition, the elastic modulus of clayey sand increased with cement content, indicating that the soil's stiffness increased with increasing cement content. It is recommended to add Ca-based binding agent at 2% to the 5S5C due to economic cost. Nearly 50% of quantity, cost and number of transportations could be saved by using the Ca-based binding agent.