BEHAVIOUR OF SILTY SAND REINFORCED WITH LOW DENSITY POLYETHYLENE (LDPE) STRIPS

In this study, silty sand is reinforced with plastic strips to improve the engineering properties of soil. Sand and silty sand soils have been used as base materials and low-density polyethylene (LDPE) strips as reinforcement materials. The LDPE strips are used in various dimensions (e.g., width ranging from 6 to 15mm and length ranging from 15 to 30mm). The randomly distributed LDPE strips are added to sand and silty sand specimens at varying percentages (e.g., 0.1% to 0.3%) by weight of dry soil specimen. Direct shear tests are performed on sand and silty sand specimens in both unreinforced and reinforced conditions. Stress strain, volumetric strain (e.g., compression/dilation behaviour) and strength envelopes are plotted to investigate the improvement in the shear strength parameter (e.g., internal friction angle). The results show that in sand specimens, the maximum improvement in shearing behaviour has been achieved with strips of 6x30mm in dimensions and at 0.3%. For silty sand specimens, the maximum improvement in shearing behaviour has been achieved with strips of 6x25mm in dimensions and at 0.3%. In addition, it has been observed that reinforced soil specimens increased the values of internal frictional angle compared to unreinforced soil specimens. In sand specimens, maximum increase of 19.72% in internal friction angle (Φ) has been observed with 6x30mm strips at similar percentage. In case of silty sand specimens, the maximum increase in internal friction angle (Φ) has been observed as 19.28% with the addition of strips of 6x25mm and at 0.3%.