Improvement of lateritic soil using shredded plastic bottles for road construction in Jos-South, Plateau State of Nigeria

Some geotechnical properties of lateritic soil treated with plastic shred were assessed. The test method employed involves treating lateritic soil with Plastic shreds in the percentages of 0%, 0.5%, 1.0%, 1.5%, and 2.0% by dry weight of soil. Test carried out include preliminary test, compaction test using British Standard light (BSL) and Unconfined compressive strength (UCS) test and shear strength test. One-way analysis of variance (ANOVA) and Regression Analysis was carried out using Microsoft Office Excel software. Percentage passing BS No 200 sieve (%) was 19.34. The MDD initially increased from its natural value of 1.70 Mg/m3  to 1.77 Mg/m3 at 0.5% PS content, while OMC increased with increase in PS. The UCS increased from 51  kN/m2 for the natural soil to 72  kN/m2 at 0.5% shredded plastic content and thereafter, a decrease in UCS was observed with further increase in the percentage of shredded plastic (1%, 1.5%, and 2%). The angle of internal friction increased by about 11% and the cohesion coefficient increased by 12%; bearing capacity increased generally with an increase in PS from 147  kN/m2 natural to 215  kN/m2 at 2%. ANOVA analysis shows that shredded plastic has a significant effect on the treated lateritic soil. Based on the result obtained, an optimal 2% of PS content improved the index and strength characteristics of the treated soil and is recommended for geotechnical engineering application based on regulatory standards.