The study of strength behavior of sandy soil mixed with plastic waste and cement slurr

Nowadays, development of the industrial societies and urbanization caused the daily rising accumulation of plastic waste and their dispersion in the nature. To decline the environmental issues of this phenomenon, different approaches are possible. The possibility of reusing plastic waste in new structure of the soil has been studied in this research. For this purpose, samples of sandy soil with dry density 1.7 gr/〖cm〗^3 and waste plastic pieces (made from mineral water bottles) with 8 × 12 mm in size(weight proportional of 0.3 %) have been mixed. Then direct shear test with fast and slow speeds 1 and 0.3 mm/min respectively in two small and large scale (10×10 and 30×30 cm, respectively), have been done in saturated condition. In the next stage, 5% of cement slurry has been added to this mixed soil and the previous tests have been repeated. The results show that adding waste plastic pieces to the sandy soil, leads to increasing the total friction angle and finally shear strength. So, for mixed soil plastic waste and cement slurry in comparison to soil without cement slurry, despite of reducing of the internal friction angle, shear strength increases from 20 to 30 percent due to significant increase in the cohesion.