Effect of relative compaction and wetting-drying cycles on desiccation cracking behavior of compacted expansive soil using digital image analysis

Abstract

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 different degrees of relative compaction on the desiccation cracking of soil. Different specimens were made using static compaction having different compaction states simulating the compaction process adopted in the construction of highway and railway embankments. The digital image analysis technique was used to quantify the crack propagation using ImageJ software. Desiccation cracks were quantified based on various crack parameters such as crack area, crack length, crack width, and crack intensity factor. Specimens with higher relative compaction exhibited reduced evaporation rates causing the delayed cracking response. A series of wetting-drying tests were also conducted to study the effect of wetting-drying cycles on the desiccation cracking response of specimens compacted at different relative compaction. Only a few cracks were observed during the compaction drying stage, followed by a large number of cracks on the application of the first wettingdrying cycle. However, the crack pattern remained almost similar in further wetting-drying cycles.