Experimental investigation on the effects of elevated temperature on geotechnical behaviour of tropical residual soils

Abstract

The engineering performance of soil after exposure to temperature is increasingly important in geotechnical and geoenvironmental engineering. Most thermal remediation of soil concentrates more on the remediation outcome and eliminates the effects temperature will have on the engineering properties of the soil itself. This paper presents the results of laboratory study conducted on two lateritic soils to investigate effect of elevated temperature difference on their geotechnical properties. The soils were classified as A-7-6 (8) and A-7-5 (4) based on the AASHTO soil classification system. After subjecting the soil samples to elevated temperatures (25, 50, 100, 150 and 200 °C), tests such as Atterberg limit, compaction, California bearing ratio (CBR), unconfined compressive strength (UCS) and scanning electron microscopy were carried on the samples. The results showed a decrease in Atterberg limit and increase in maximum dry density. The peak CBR for both the soils was obtained at 150 °C. The UCS increased with curing time but decreased with increased preheat temperature for both soils. The microanalysis result portrayed changes in morphological structure of fabrics which indicates a breakdown in the microstructural properties of the soil due to temperature variation. Generally, the statistical analysis of variance showed that temperature has significant effect on the geotechnical properties of residual soils.