Characterisation of recycled mixed plastic solid wastes: Coupon and full-scale investigation

In Australia, the plastic solid waste (PSW) comprises 16% by weight of municipal solid waste but only about one-fourth are recycled. One of the best options to increase the recycling rate of mixed PSW is to convert them into products suitable for construction. However, a comprehensive understanding on the mechanical behaviour of mixed PSW under different loading conditions is important for their widespread use as a construction material. This study focuses on investigating the mechanical behaviour of recycled mixed PSW containing HDPE, LDPE and PP using coupon and full-scale specimens. From coupon test, the strength values were found to be 14.8, 19.8, 20, 5.6MPa in tension, compression, flexure and shear respectively, while the modulus of elasticity are 0.91, 1.03, 0.72GPa in tension, compression and flexure respectively. The coefficient of variance of the measured properties for coupon and fullscale specimens was less than 10% indicating that consistent material properties can be obtained for mixed PSW. More importantly, the strength properties of mixed PSW are comparable to softwood structural timber. The flexural behaviour of full-scale specimens was also predicted using fibre model analysis and finite element modelling. Comparison showed that using coupon specimen's properties, the flexural behaviour of the full-scale specimens can be predicted reliably which can eliminate the costly and time consuming arrangements for full-scale experimental tests.