Shaking Table Study on PET Strips-Sand Mixtures Using Laminar Box Modelling

Daily increase in plastic waste amounts is a serious environmental problem and it is among the major challenges worldwide. Reusing this waste material can be therefore an appropriate solution to overcome this problem. Besides, recycling plastic waste as reinforcing material has become a cheap and viable alternative for soil improvement schemes. In the current study, PET plastic waste strips (water bottles) were randomly mixed with sandy soil to improve the soil strength parameters. Due to the lack of comprehensive seismic studies on soils reinforced with PET strips, a series of 1-g shaking table tests was performed to evaluate the dynamic properties of the sand-PET mixtures with different PET contents (0%, 0.5%, 0.75% and 1% by the sand weight) and aspect ratios (1 and 5). Effect of various parameters, including excitation amplitude, PET strip content and PET strip aspect ratio on response of the mixtures were elaborated. It was found that addition of the PET strips to the sand, could reduce the soil brittleness under low overburden pressures. Therefore, at the inclusion ranges used in this study, increase of the PET strips content or aspect ratio, caused an increase in the damping ratio and decrease in the shear modulus values compared to the plain sand model. Opposite trends of PET strips inclusion contribution were reported under the influence of high overburden pressures through carrying out some cyclic large-scale direct shear tests.