Experimental Study on Compressive Strength and Water Absorption of Paving Blocks Incorporating Polypropylene Plastic Waste

Abstract

 

Plastic waste, particularly polypropylene (PP), poses a serious environmental challenge due to its resistance to natural degradation and long persistence in landfills. This study investigates the feasibility of utilizing polypropylene plastic waste as a partial or full substitute for conventional binder materials in paving block production. Experimental paving blocks measuring 200 × 100 × 60 mm were manufactured using five mix proportions of polypropylene plastic waste and sand: 100% PP, 90% PP:10% sand, 80% PP:20% sand, 70% PP:30% sand, and 60% PP:40% sand. Compressive strength tests were conducted at curing ages of 7 and 28 days, while water absorption tests were performed at 7 days. The results indicate that the compressive strength of paving blocks decreased with increasing polypropylene content, with the lowest strength observed in the 100% PP mixture (5.5 MPa at 7 days and 4.0 MPa at 28 days). The highest compressive strength was obtained from the 60% PP:40% sand mixture, reaching 9.6 MPa at 7 days. Water absorption values ranged from 1.39% to 2.36%, reflecting the hydrophobic nature of polypropylene. However, none of the tested mixtures fully satisfied the requirements of SNI 03-0691 (1996). These findings suggest that polypropylene plastic waste has potential for non-structural paving applications, particularly pedestrian pathways, while also contributing to plastic waste reduction.