Desiccation crack initiation and propagation in clay with MgO

Abstract

<p>As a natural phenomenon in near-surface soils, desiccation cracks are affected by various factors including clay type and water content. In this study, the effect of Magnesium Oxide (MgO) addictive on soil hydraulic and cracking properties was investigated. The effect of MgO and MgO content on the desiccation cracking of kaolinite clay was conducted with laboratory tests. The water content and the water evaporation rate were measured during drying. The result shows that the MgO addictive decreased the water evaporation of clay. A digital image-capturing system was applied to analyse the cracks propagation and features during desiccation. The results demonstrate a significant influence of MgO on the cracking behaviour of kaolinite clay subject to desiccation. The addition of the MgO increased the number of cracking segments, cracking length per unit area, and cracking area. However, there was a reduction of the cracking width with the addition of MgO. Moreover, with the increase of MgO content in the soil, more cracking was generated. This research provides insight into the desiccation process of clay containing MgO with respect to water evaporation, shrinkage, and cracking.</p>