Desiccation cracking in lime-treated expansive soil under cyclic wetting and drying

The present study quantifies the impact of cyclic wetting�drying (W�D) on the desiccation cracking behavior of lime-treated compacted expansive soils using Digital Image Analysis techniques. Lime was added in dosages of 0, 2, 4 and 6%. Small disc-shaped specimens were subjected to a total of five gentle wetting�drying cycles inside the laboratory to simulate the seasonal climatic variations. Digital images of the top and bottom surfaces of specimens were captured during the drying cycles. These images were used to quantify various crack morphological parameters, such as total area of cracks, crack intensity factor, total crack length, average crack width, etc., using digital image analysis tools. The impact of desiccation cracks and W�D cycles on volume change and compressibility characteristics was also explored. The results of this study indicated that higher lime contents (>?4%) allowed very little transfer of cracking from the top to bottom surface of the specimen compared to 0 and 2% lime-treated specimens. The crack morphological parameters increased with the number of W�D cycles in specimens treated with 4% or more lime, yet they were always lower than in untreated soil. The swelling nature and compressibility of untreated soil were reduced with W�D cycles, whereas lime-treated specimens showed a completely reverse behavior. These results indicated the deteriorating effects of W�D cycles on lime-treated soil due to the breakdown of cementitious bonds.