Evaluation of the Effect of Cement Reject, Fiber Glass and Plastic (PET bottle) Wastes on the Stabilization of Clay Soil

Abstract

This study presents an evaluation of use of the cement waste as chemical stabilizers and recycling fiber glass wastes and plastic waste (PET Bottles) as soil reinforcement, for improving the strength and stability of soils. An experimental program was conducted to investigate the effect of materials waste and evaluate the efficiency of their use on clay soil as stabilizers, this was achieved based on a study of the effect of materials waste on the properties of clay soil such as optimum moisture content (OMC), maximum dry density and shear strength parameters (cohesion(c) and angle of friction (ɸ)). The aim was to determine the optimum content of each of these materials waste and consequently, to reduce the pollution which results from accumulation of (plastics waste (PET: Polyethylene Teraphathalate), fiber glass and cement waste). A series of laboratory compaction, triaxial and California Bearing Capacity (CBR) tests were carried out. Various percentages of cement waste (3, 6, 9, 12 and 15%) of dry weight of soil was added to clay soil and tested. Also soil was reinforced randomly by different percentage (0.5, 1.5, 3, 6, 9 and 12 %) of dry weight of soil by fiber glass (length 10-30mm) and Plastic (PET) bottles strips waste (length and width (5-10mm)). Soil specimens were compacted at maximum dry density. Results of soil treated by cement waste indicate that addition of cement waste increased the shear strength (385.38 mPa at age 2hours) and CBR ()to a maximum value for up to 9% addition, when the percentage of addition of cement waste was equal to or greater than 9% soil became non plastic. The OMC decreased with an increase of more than 12% of cement ~ V ~ waste content. The dry density of the soil decreased from 1.56 to 1.48 g/cm3 with an increasing of cement waste content. ` Results of soil reinforced by fiber glass and PET bottle indicate that an increasing of fiber glass and plastic bottle content decreased the maximum dry density and increased the OMC. The highest increase in strength value (386.82 mPa) was achieved when the soil was reinforced by 3.0 % of fiber glass content and (386 mPa) when the soil was reinforced by 1.5% of plastic bottle content and the highest CBR value was achieved at 3.0% of fiber glass and PET bottle content respectively. The highest CBR value was 8.3 times the CBR of natural clay soil for soil treated by cement waste, 3.6 times the CBR of natural clay soil for soil reinforced by fiber glass and 2.1 times the CBR of natural clay soil for reinforced by PET bottle waste. As a result of this study it is recommended to use not more than 9% of cement waste, 3% fiber glass waste and (1.5% to 3%) PET bottle waste as stabilizers to improve the shear strength and CBR of clayey soil.