Use of Recycled Plastic Fibers to Control Shrinkage and Desiccation Cracking in Clayey Soils

Abstract

Two main issues are addressed in this work. The first issue is environmental concerns about managing plastic waste on a large scale by promoting reuse with low energy requirements in the recycling processes. The second issue is the desiccation cracks in fine soils, induced by prolonged droughts, which have motivated the interest in mitigating the adverse effects on the stability of geotechnical works using recycled materials. Therefore, this work addresses a strategy based on the use of recycled polyethylene terephthalate (PET) and polypropylene (PP) fibers for the reinforcement of soils prone to cracking. To evaluate the effectiveness of plastic fibers in controlling soil volumetric changes and cracking during drying, several experiments were conducted in an environmental chamber to properly simulate and monitor the desiccation process. Image analysis and suction measurements provided several metrics and parameters, and their usefulness is discussed in detail, both for the unconventional determination of the optimum fiber content by weight with 100% effectiveness in preventing cracking and for correlating fiber content with reductions in shrinkage and cracking patterns, thus contributing to the understanding of the behavior of fiber-reinforced soils. Finally, examples of large-scale applications of recycled plastic fibers in geotechnical works are proposed, and the positive environmental impact is estimated.