Influence of recycled shredded PET on the subgrade strength of SW-SM and ML soils

Lucero Chugnas Jambo S.; Rocío Villanueva Bazán L. · Proceedings of the LACCEI international Multi-conference for Engineering, Education and Technology (2026) · DOI: 10.18687/laccei2026.1.1.974

Resumen

This research evaluated the influence of adding recycled and shredded PET on the stabilization of SW-SM (silty sands) and ML (silts) soils collected in the Baños del Inca district, Cajamarca. The methodology employed was applied and experimental, utilizing Modified Proctor and CBR tests following ASTM and NTP standards. Initially, the SW-SM soil had a CBR of 12.30%, while the ML soil had a value of 9.80%. When PET was added in proportions of 1%, 3%, and 5%, the mixture with 5% PET proved to be the most efficient, increasing the strength of the SW-SM soil to 17.80% (a 44.71% improvement) and the ML soil to 14.10% (a 43.88% improvement). The results indicate that the shredded PET flakes not only fill gaps but also improve load transfer thanks to mechanical bonding due to their rough texture. Furthermore, because they do not absorb water, PET maintains soil firmness even under saturated conditions, which is vital for subgrade stability. It is concluded that this polymer allows for the reclassification of mediocre soils into high-quality subgrades. This reduces costs and offers a sustainable solution aligned with the SDGs by giving a new use to polluting plastic waste.

Instituciones: Universidad Privada del Norte