Evaluation of compacted laterite soil admixed with cement and hair fibers as road construction material

Abstract

Natural laterite soil, classified as A-5 (4) based on American Association of State Highway and Transportation Officials (AASHTO) soil classification system and ML-CL according to Unified Soil Classification System (USCS), was admixed with ordinary Portland cement and synthetic hair fibers (SHF) were evaluated as road construction material. Soil specimens were made by mixing lateritic soil with up to 4% cement in 1 % step concentration and up to 12% SHF in 2 % step concentration of by dry weight of the soil and subjected to British Standard Light (BSL) or Standard Proctor method of compaction, unconfined compressive strength (UCS), and California bearing ratio (CBR) tests. Results indicated a decrease in the values of optimum moisture content (OMC), while no general trend was established for maximum dry density (MDD). The values of UCS and CBR increased as the content of both cement and SHF increased. Analysis of variance (ANOVA) of the results shows some level of significance on some geotechnical properties considered. Regression analysis on the results shows that MDD, OMC, cement, and SHF significantly influenced the UCS and CBR values of the stabilized soil with correlation coefficient values (R2) of 82.9 and 83.3%, respectively. Based on the results, an optimal blend of 3% cement 9% SHF significantly improved the soil properties and is recommended for improving the geotechnical properties of lateritic soil treated with cement/ synthetic hair fiber as road construction material.