การปรับปรุงดินลูกรังด้อยมาตรฐานด้วยวัสดุผสมซีเมนต์-โพลีเมอร์

Abstract

This research presents the improvement of sub-standard lateritic soil using cement-polymer mixtures. Mixing polymer into cement to create such a cement-polymer mixture could cause the cement use reduction in the cement stabilization technique for roadway applications. Cement as a soil stabilizing agent has been popularly used to stabilize any sub-standard materials for the road. However, the cement-stabilized material has relatively less flexural strength and still prone to have a moisture sensitivity characteristic even it can provide good compressive strength. This study aims to determine a proper ratio between cement and polymer for using as a stabilizing agent for sub-standard lateritic soil. This polymer would assist gaining more flexural strength and less moisture sensitivity for such cement-stabilized lateritic soil. In this study, the cement-polymer mixtures in forms of the paste were investigated with cement type 1, styrene acrylic (SA) and styrene butadiene rubber (SBR) polymers to make a new type of laterite binder with varying the polymer content of 0, 5, 10, 15, 20% by dry mass of cement. Cement-polymer paste samples were cured for 7 and 28 days before a series of the compressive strength tests, the flexural strength tests, and the water absorption tests. The results revealed that the 10% polymer (SA) and 15% polymer (SBR) content of cement can provide the best compressive strength with better flexural strength and least water absorption compared to other mixtures. With this proper ratio of cement : Styrene acrylic (SA) polymer of 90 : 10 and Styrene butadiene rubber (SBR) of 85 : 15 is used as a binder varying the cement content 2, 4, 6, 8 and 10% by dry mass of sub-standard lateritic soil. The unconfined compressive strength test and water absorption test were tested to determine the appropriate amount for improving sub-standard lateral soil. It was found that cement : styrene acrylic (SA) and styrene butadiene rubber (SBR) that standardized laterite were used at equal amounts of 1.6% and 2.4%. The cement modified part used the amount equal to 3.3% which can reduce the consumption of binder and cement-polymer mixtures can prevent more moisture than normal cement. With this proper ratio, it can be further used in stabilizing the sub-standard lateritic soil for roadway application.