Geotechnical and Geo-environmental Properties of Discrete Polyester Fibre-reinforced and RBI Grade-81-stabilized Clay and Sand

Abstract

The present study evaluated the geotechnical and geo-environmental properties of both clay and sand reinforced with discrete polyester fibre of length 12 mm and stabilized with chemical stabilizer RBI Grade-81. The soils were mixed with RBI Grade-81 content of 1%, 2%, 3% and 4% and fibre content of 0.25%, 0.50%, 0.75% and 1.0% of dry mass of soil for determining their individual and combined effect on different geotechnical properties. Additionally, X-ray diffraction analysis (XRD) and scanning electron microscopy (SEM) tests were also carried out to know the mineralogy and micro-structure of the hydrated products formed during the stabilization. Leachate obtained from the stabilized soils was tested for concentration of heavy metals and were found well within limits prescribed by the United States Environmental Protection Agency for hazardous waste. The results indicated that the mechanical strength parameters of the soils had significantly enhanced with the use of RBI Grade-81 and polyester fibre which was corroborated by XRD and SEM results. The clay showed higher improvement in its mechanical behaviour than that of sand. The inclusion of fibre changed the RBI Grade-81 treated soil's brittle behaviour into ductile behaviour. The results obtained were indicative of the safe and environment-friendly use of RBI Grade-81 and polyester fibre for use in road construction.