Experimental and statistical analysis of soil stabilization to avoid landfilling

Clayey soil is a moisture-sensitive material whose properties pose geo-environmental challenges in the construction sector. Soil stabilisation through lime treatment offers the possibility of using local unsuitable soils without landfilling. This study investigates the lime treatment and stabilisation of sensitive reddish clay soils from the Setif region, Algeria. Geotechnical, chemical, and physic-chemical characterisation of the clayey soils with different percentages of dry lime (i.e. 0 % to 9 % by weight with intervals of 3 %) were conducted. The standard plasticity test shows that the lime treatment causes a decrease in the plasticity index (from 30.7 to 22.1 %) and methylene blue value (from 5 % to 2.71 %). Furthermore, the compressive strength test showed a 16-fold increase in unconfined compressive strength (UCS) after 28 days for the clay with 6 % lime (130 kPa versus 2 100 kPa). However, a decrease in dry density was also observed (16 kN m−3 versus 15.7 kN m−3). Chemical and physic-chemical analyses using X-ray fluorescence and diffraction revealed the appearance of other chemical elements and mineral phases. Finally, ANalysis Of VAriance (ANOVA) was used to evaluate the effect of curing time and lime content on UCS. Both variables affected the strength development positively. The lime content was two times more efficient than the curing time.