Assessment of the Desiccation Cracking Characteristics of Clay Reinforced with Fibers Utilizing the Distributed Optical Fiber Sensing (DOFS) Technique

Desiccation cracking of clay can significantly affect its mechanical and hydraulic performance. Discrete fiber reinforcement is known to be an effective method for prevention of desiccation cracking in clays. This study reports a physical evidence-based investigation of the evaluation of desiccation cracking behavior in fiber-reinforced clay using a high spatial resolution (5.12 mm) distributed optical fiber sensing technique. Acrylate-coated optical fiber sensors were chosen and buried directly in unreinforced and fiber-reinforced expansive clay specimens. Four different configurations (unreinforced expansive clay specimen, 6 mm, 12 mm, and 18 mm PP fiber-reinforced expansive clay specimens) were prepared in rectangular linear shrinkage containers and subjected to desiccation in controlled environmental conditions. The strain measured by DOFS was analyzed to study the crack initiation and crack propagation in unreinforced and PP fiber-reinforced specimens. A digital image acquisition system was used to measure the shrinkage strains developed on the top surface of the clay specimen, which were then analyzed using the digital image correlation technique. The results elucidate essential insights into the desiccation cracking behavior of fiber-reinforced expansive clay, including location of crack initiation and intensity of crack propagation due to bridging action of fibers. In particular, PP fiber-reinforced clay specimens effectively restrained desiccation cracking due to the formation of small and localized microcracks compared to unreinforced clay.