Engineering behaviour of lime- and waste ceramic dust-stabilized expansive soil under continuous leaching

Abstract

Numerous distresses in pavement structures on chemically stabilized expansive soils have raised considerable debate regarding the long-term performance of lime-stabilized subgrades. Therefore, this paper examines the effects of continuous leaching on the durability of lime- and waste ceramic dust (WCD)-stabilized expansive subgrades. The tests were performed with different percentages of quicklime (3.5, 4.5, 5 and 10%), while the combined effects of lime and WCD were evaluated by adding 1.5% of WCD to the mixtures containing 3.5 and 4.5% lime. Geotechnical tests such as Atterberg limits, compaction and California bearing ratio (CBR), in addition to microstructural and leachate analyses, were used to evaluate the engineering properties of the stabilized soils. The CBR result shows that early strength development occurred in the soils mixed with lime and WCD. However, at longer curing periods, the beneficial effect of lime on the engineering properties of the soil increased with an increase in lime content. Results of the leaching tests show considerable changes in the physicochemical properties of the soil mixtures, while the estimated service life of the stabilized soils increased from 3.4 to 9.2 years, as lime content increased from 3.5 to 10%. Microstructural analysis results reveal that the flocculated nature of the soil fabric and the density of the fibrous cementitious compounds increased with an increase in lime content. This study clearly indicates that electrical conductivity, pH and pore-water cation concentrations can be used in combination with geotechnical tests, to correctly evaluate the durability of lime- and lime-WCD-stabilized expansive soils.