Analysis of Tensile Strength in a Combination of Recycled HDPE Plastic and Liquid Asphalt

Abstract

Plastic waste reuse has gained significant attention due to its potential to reduce environmental pollution and provide alternative materials for engineering applications, particularly in the construction sector where durability and maintenance issues are common. One persistent problem in building structures is roof leakage caused by long-term exposure to rainfall, ultraviolet radiation, and extreme temperature changes, which gradually damage conventional waterproofing materials. To improve performance, materials with higher tensile strength and flexibility are needed. High-Density Polyethylene (HDPE), a thermoplastic known for its strength and durability, offers promising reinforcement when combined with liquid asphalt, while also supporting environmentally sustainable practices by reducing plastic waste. In this study, liquid asphalt was heated to 40°C and mixed with HDPE heated at 200°C, 210°C, and 220°C, then stirred for 1.5 hours until homogeneous, cooled to room temperature, and molded according to ASTM D638 for tensile testing. The results show that the 90:10 (HDPE: asphalt) composition at 200°C produced the highest tensile strength of 6.14 MPa, while the 80:20 composition at 220°C showed the lowest value of 3.86 MPa, indicating that higher HDPE content at optimal melting temperatures enhances mechanical properties and provides strong potential for use as a durable, environmentally friendly waterproofing layer in building construction.