High-density polyethylene (HDPE) to augment fat clay soil using consolidation method

Abstract

The production of plastic in the Philippines has reached the peak point where proper disposal and recycling are minimal, remarking the country as the third-largest contributor of plastic waste worldwide. In the Philippines, the production of plastic pipes using cutting-edge technology results in significant volumes of high-density polyethylene (HDPE) sawdust. To examine the potential use of this plastic trash as an additive to strengthen fat clay soils, the researchers conducted an extensive experiment on local clay soils in Davao City mixed with HDPE sawdust in levels ranging from 0% to 12% by weight. Laboratory tests included soil classification using Unified Classification System (USCS), grain size analysis, Atterberg limit, and one-dimensional consolidation. The study looked at how increasing the HDPE contents affected the natural characteristics of local clay soils. According to the findings, the projected settlement rises significantly as the additive increases; however, a Scheffe test was performed, and it was discovered that 2% and 5% HDPE content, with projected settlements of 32.33 mm and 49.33 mm, respectively, are statistically the same and are also closer to the value of 0%, which has the lowest projected settlement of 22 mm. It has been shown that adding 5% plastic to fat clay soil improves its engineering attributes without degrading the soil's quality. Consequently, the findings of the experimental study on reinforced plastic sawdust soil demonstrated that plastic might be utilized as an efficient addition to addressing the problem of waste disposal and an affordable alternative for reinforcing fat clay soils.