A study on desiccation cracking behavior of polyester fiber-reinforced expansive clay

Abstract Expansive clays swell in presence of the water and shrink in its absence, thereby producing desiccation cracks which significantly alter its mechanical and hydraulic performance. In this study, the improvement in the crack resistance of locally available expansive clay by polyester fiber reinforcement was investigated. Laboratory tests were conducted to quantitatively evaluate the effect of fiber content and fiber length on desiccation cracking of fiber reinforced clay. The alkaline stability of the polyester fibers was tested by exposing the fibers to harsh alkaline environment and was found to be suitable for the soil under consideration in barrier systems. A digital image acquisition system was employed to capture the evolution and propagation of cracks in the soil specimen subjected to desiccation. The results demonstrate a significant influence of fiber reinforcement on the cracking behavior of expansive clay at the onset of desiccation. The average crack opening width, the spacing of cracks and the average cell area were measured and compared with those of unreinforced specimen. In fiber reinforced clay, a noticeable reduction in the total cracked area, which is due to the presence of fibers, has been observed. The crack intensity factor (ratio of the area of the cracks to the total specimen area), the average width, the spacing of cracks and the cell area decreased with fiber inclusion, thereby increasing the relative integrity of the specimen relatively. The average shrinkage strain for unreinforced and fiber-reinforced soil specimen was also determined. Fiber reinforcement was found to be effective in restraining desiccation cracking except when longer fibers were used.