Reinforcing Sand with Strips of Reclaimed High‐Density Polyethylene

Abstract

The feasibility of reinforcing soil with strips of reclaimed high‐density polyethylene (HDPE) was investigated in this study. Strips of HDPE were mixed with Portage sand and tested to determine the California Bearing Ratio (CBR), secant modulus, resilient modulus, and shear strength. Strips were prepared at aspect ratios of 4, 8, and 12 to examine how reinforcement of the sand is affected by the length of the strips. The tests showed that reinforcing sand with reclaimed HDPE strips enhances its resistance to deformation and increases its strength. Addition of strips increased the CBR and the secant modulus, with the CBR increasing by as much as a factor of 5. The resilient modulus also increased with addition of strips, with the greatest increases (35% increase) occurring for strip a content of 3%. Direct shear tests also showed that addition of HDPE strips increased the shear strength of the sand. Increases in friction angle as large as 18° were measured at normal stresses below the critical confining stress. Reinforcement was affected by the aspect ratio (or length) of the strips. The largest increases in all measured properties were observed for strips having an aspect ratio of 8. In some cases when an aspect ratio of 4 was used (short strips), the soil became weaker.