Effect of Lime on Crack Propagation in Compacted Expansive Soil over a Range of Moisture Fluctuation: An Image-Based Approach

Compacted expansive soil undergoes swelling and shrinkage during seasonal moisture fluctuations and causes distress to highway and railway structures built over them. Shrinkage of expansive soil is accompanied by the development of large desiccation cracks. The present research work is focused on studying the effect of lime treatment on crack propagation characteristics of compacted expansive soil along with its shrinkage response. Soil-shrinkage curves (SSC) were obtained for both untreated and lime treated compacted expansive soil specimens. Digital images of soil specimens were captured during the desiccation process. A Python program was developed to study the evolution of desiccation cracks by performing digital image analysis. A marked reduction in the rate of shrinkage process was observed accompanied with 36.4% reduction in volumetric shrinkage at 6% lime addition. Crack analysis results showed an increase in the intensity of cracks on lime addition followed by reduction in crack width, higher crack network connectivity, and microcracking phenomenon.