Experimental Study on the Static and Dynamic Properties of Silty Sand Mixed with HDPE

Recycling and reusing plastic waste are an environmentally friendly solution to help reduce the demand for landfill space. This study aimed to investigate the static and dynamic properties of silty sand stabilized by high-density polyethylene (HDPE) from plastic waste. The laboratory tests include of compaction, consolidation, direct shear, large-scale oedometer and large-scale cyclic direct shear tests were performed to examine the geotechnical properties of the HDPE-sand mixture. Five HDPE contents (0, 2, 4, 6, and 8%) were chosen. The experimental tests indicated that the addition of HDPE chips to the soil as an environmentally friendly solution, significantly affects the static and dynamic properties of silty sands. The maximum dry density of the mixtures decreased with increasing the HDPE content due to HDPE's low specific gravity. The addition of HDPE to sand increased the friction angle and thus improved its shear strength due to the interlocking capacity between the soil and HDPE. The mixture's strength improved and its compressibility significantly increased. The damping ratio of the mixture was also promoted compared to silty sand without HDPE, but the shear modulus declined. The incorporation of 8% HDPE has led to the greatest increase in the damping ratio (up to 23.3%) at displacement semi-amplitude (Aw)\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$({A}_{w})$$\end{document} = 2 mm. At the same HDPE content and Aw\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${A}_{w}$$\end{document} (8% and 2 mm, respectively), cyclic shear stress in mixtures increased up to 38%.