Reuse of non-degradable waste PET bottles for ground improvement

This paper describes California bearing ratio (CBR) tests carried out to investigate the suitability of waste polyethylene terephthalate (PET) bottles for ground improvement. For the studies, quarry dust is used as an infill, and it is prepared at a relative density of 57.6% within the CBR mould with a diameter of 150 mm. Experiments are carried out by embedding cut PET bottles with a diameter of 5.6 cm within the infill to provide cellular confinement in three different configurations, i.e. three-bottle, four-bottle and five-bottle configurations. The effect of bottle height on the performance of the systems is investigated by considering three cell (bottle) heights, viz., 6.6 cm, 9.3 cm and 11.6 cm. To analyse the performance of the cellular confinement, vertical stress distribution below the applied load is determined. It is observed that the performance of the PET bottle embedded system is better when it is placed within the isobar (sigma z/q) of 0.3. Based on the CBR values and improvement factor, it is observed that a four-bottle configuration with a height of 6.6 cm is effective in sustaining higher loads. The proposed study provides guidelines for using these bottles for stabilising blocked pavements.