Experimental Study on the Effect of Plastic Waste Strips and Waste Brick Powder on Strength Parameters of Expansive Soils

Abstract

Expansive soils are found abundantly in Ethiopia. This type of soils is weaker, having low strength and load resisting characteristics in nature due to their difficulty in volume change when it comes into contact with water. The volume of such soils becomes swell when saturated with water and shrinks during dry seasons. In civil infrastructure construction, such soil either should removed or improved to be used as foundation soil. Removing the soil leads to the more extra costs of construction. Improving, on the other hand, requires increasing the stiffness and load-carrying capacity of the road by treating it with stabilizers, which helps in achieving a low cost and good performance. This study aimed at treating such soils with waste materials for improving the strength of the soil against pressure, and to reduce environmental pollution. In this study, locally available black cotton soil is treated with brick waste powder (20, 30, and 40 %) and plastic strips with (0.25 %, 0.5 %, and 0.75 %) percentages in weight. Different tests including atterberg limits, compaction, CBR, and unconfined compressive strength were performed to find an optimum percentage of mixes. Many trials were done by varying the percentages of PWS (plastic waste strips) and BP (brick powder). At an addition of 0.75% PWS and 30% BP, significant change was observed with huge improvement in CBR, free swell and unconfined compressive strength values.