Use of glutinous rice slurry for reducing compressibility and cracking potential of kaolin and lime-treated kaolin

Compressibility and cracking potential are two main problems commonly associated with clay soils. Previous studies have proven that lime is useful in improving the shear strength and compressibility of clay. However, it also increases the brittleness of the soil, leading to a higher potential for crack formation when subjected to repetitive wetting and drying cycles. The present study attempted to explore the potential of using an ancient construction material, namely glutinous rice slurry, to improve the compressibility and cracking potential of pure kaolin and lime-treated kaolin. The lime concentration was fixed at 10%, while the glutinous rice slurry was prepared at concentrations of 2%, 4%, 6%, and 8%. The soil samples were subjected to Atterberg limit tests, 1D consolidation tests, and desiccation tests. The results showed that the lime-treated kaolin yielded the most improved plasticity behavior (the plasticity index was reduced from 17.9 to 7.8). The compressibility of the kaolin was best improved by adding 2% of glutinous rice slurry only. The compression index of the soil was successfully reduced from 0.158 to 0.079. The desiccation test indicated that the lime-treated kaolin showed a great tendency towards large crack formation, while the glutinous rice slurry-improved kaolin exhibited a great tendency towards swelling/shrinkage when subjected to repetitive wetting and drying cycles. The kaolin treated with 10% lime and 2% glutinous rice slurry showed the greatest resilience towards crack formation. Despite the fact that the combination of lime and glutinous rice slurry did not yield the greatest improvement in soil compressibility, the glutinous rice slurry was capable of neutralizing the brittleness caused by lime, while creating strong bonds in the soil to resist surface tension, shrink and swell behavior, and reduce soil compressibility. The compression index of the glutinous rice slurry-improved lime-treated kaolin was 25% lower than that of the pure kaolin.