Influence of Grain Size Distribution into the Desiccated Crack Behavior of Lateritic Soil

Lateritic soil is rusty-colored soil rich in iron oxide (Fe and Al). Its cracking properties are controlled mainly by the environmental conditions it has been exposed to and the lateritic soil's mineralogical composition. The study area is located at Sungai Merab, Bangi, Selangor, with lateritic soils dominating the landscape. Two samples, (S-O) and (S-F), each with in-situ and fine-grained grain size distribution, were prepared to assess the influence of grain size distribution on the desiccated crack behavior of lateritic soil. The S-O sample contains the original soil composition of the field, whereas the S-F sample is sieved soil that has been passed through a 0.075 mm sieve. The samples were placed in a 24.5 × 17 cm rectangular pan and air-dried in a temperature-controlled room (24.5℃) to achieve desiccation. Four cracking stages can be identified based on the laboratory simulation: namely, the internal drying stage, the surface drying stage, the advanced cracking stage, and the equilibrium stage. The onset of desiccated crack for S-O and S-F samples are on the 9th and 11th days of drying, respectively. Both samples stopped cracking on the 20th and 21st days of drying, respectively. The S-O sample shows higher crack intensity, angularity, and smaller crack segments than the S-F sample. However, the cracking angles for both soil conditions were similar. The desiccated crack behavior of lateritic soils was influenced by the grain size distribution, with finer soils exhibiting a more regularized crack morphological pattern than in-situ soil.