Effect of Lime on Silty Clay for Use in Road Construction

This study evaluates the effect of quicklime on the geotechnical properties of silty clay used in road construction. The addition of 2% to 10% quicklime modified the grain size through flocculation, thereby improving the performance properties of the material. The mechanical properties of the material improved with 2% to 4% quicklime. Above a content of 4%, considered to be the fixing point of the lime, the mechanical properties decreased and no longer improved. The CBR indices obtained with 2% to 6% lime were above the minimum of 30% and could be used in road foundation layers. The rigidity of the material obtained after treating the soil with quicklime allows the material obtained after mixing to perform well in hot weather, without deformation or rutting when subjected to traffic. This is because lime binds the fine clay particles into much larger particles after flocculation, which are more or less impermeable on the surface and reduce material degradation due to crumbling and abrasion, which are responsible for road surface deterioration. Subsequently, the friction of the grains under the stress exerted by the hammering of the tyres consolidates the mechanical bonds during setting, slowing down the wear of the particles that generate plastic fines.