Cement-lime stabilization of crude oil contaminated kaolin clay

Abstract

Abstract The present study examines the effect of stabilization on the geo-environmental properties of crude oil contaminated kaolin clay. Lime and cement were mixed in a ratio of 1:2 and added to the simulated crude oil contaminated kaolin clay at different percentages (5%, 10%, 15%, and 20%) as a stabilizing binder. Parameters investigated include consistency limits, unconfined compressive strength (UCS), and direct shear, and compressibility and leaching characteristics of the untreated and stabilized soils. The experimental testing reveals a decrease in the consistency limits with addition of the stabilizing binder. Maximum UCS values occurred for 15% cement-lime stabilized kaolin clay at different curing periods (i.e. 0 d, 7 d, 14 d, and 28 d). By increasing the cement-lime content from 5% to 15%, the UCS values of the stabilized clay increase from 185 kPa to 350 kPa and from 785 kPa to 1160 kPa for uncured and 28 d-cured samples, respectively. Both the compression and recompression indices of the contaminated kaolin clay from the consolidation test decrease by 40% and 50%, respectively, with 20% stabilizing binder addition. The leachability of the contaminated clay also reduces with incorporation of cement and lime. According to the scanning electron microscope (SEM) test, addition of stabilizing binder transforms the dispersed structure of contaminated kaolin clay into a knitted flocculated structure. The study shows the effectiveness of cement-lime mix in stabilizing the contaminated kaolin clay and the possible use of stabilized contaminated kaolin clay as an alternative construction material.