Development and Characterization of Termite Mound Clay Reinforced HDPE Composite Under Low Strain Rate

Abstract

In recent years, composite materials have gained significant attention due to their environmental sustainability, economic efficiency, durability, and enhanced mechanical performance. This study focuses on the development and characterisation of termite mound clay reinforced high-density polyethene (HDPE) composites aimed at improving resistance to low-strain-rate impacts. Specimens were manufactured according to ASTM standards using a Design of Experiments (DOE) approach. Three variables were considered: plastic weight ratio (90%, 80%, 70%), mixing time (5, 15, 25 minutes), and clay particle size (63–90, 90–125, 125–150 μm). Nine experimental combinations with three replications were produced. Mechanical testing was conducted under low strain rate conditions, with tensile testing performed at 6.67 × 10⁻³ s⁻¹ and flexural testing at 10⁻³ s⁻¹ (20 mm/min cross head speed), alongside impact evaluation. Physical properties, including density and water absorption, were also assessed. The results demonstrated improved mechanical performance, with maximum tensile, flexural, and impact strengths of 22.73 MPa, 90.65 MPa, and 15.67 kJ/m², respectively. The highest density recorded was 1.266 g/cm³, comparable to pure HDPE, while water absorption remained low at 0.28%. Statistical analysis using Minitab 19 indicated that plastic weight ratio significantly influenced flexural strength, whereas other factors showed limited statistical significance. Optimization identified 90% plastic content, approximately 7 minutes mixing time, and 90–125 μm particle size as the best-performing combination. Overall, termite mound clay reinforcement enhanced the physical and mechanical behaviour of recycled HDPE, indicating suitability for applications such as protective soft body Armor.