Discussion: Effects of plastic waste materials on geotechnical properties of clayey soil [DOI: 10.1007/s40515‑020‑00145‑4]

Abstract

The paper under discussion (by Hassan et al. (2021)) presents a comprehensive set of experimental results from standard geotechnical laboratory tests performed on a low-plasticity clay soil (CL) amended with between 1% and 4% (by weight of dry soil) of randomly distributed discrete polyethylene terephthalate (PET) and polypropylene (PP) fibers, each blended with the soil in two fiber lengths. These fibers were prepared by cutting into two sizes waste PET water bottles and woven PP bags, each in fiber lengths of 1.0 and 2.0 cm, and in widths of 2.5–3.0 mm. While stated in the Abstract of their paper that “it is important to find methods to manage these waste materials without causing any ecological hazards,” based on the authors’ experimental bench-scale investigation, they concluded that the described PET and PP fibers can be efficiently used to improve the physical and strength properties of soil materials as foundations for engineering projects, including improvement of the CBR and resilient modulus of clayey subgrade soils for sustainable road construction.