Sustainable Lightweight Wall Panels: Comparative Performance Evaluation Of Polyurethane Foam Incorporated Cement Concrete And Geopolymer Concrete Under Axial And Flexural Loading

Abstract

This study investigates the use of Polyurethane Foam (PUF) as a partial replacement for fine aggregate (0–20%) in Normal Concrete (NC) using Ordinary Portland Cement (OPC) and Fly Ash-GGBS-based Geopolymer Concrete (GPC) wall panels of size 1000 × 300 × 50 mm. All panels were reinforced using mild steel wire mesh (30 × 30 mm grid, Ø3 mm) and tested under axial compression and flexural loading to evaluate key performance metrics such as workability, strength, stiffness, and failure characteristics. Workability decreased with increasing PUF content, with the OPC slump reducing from 95 mm to 70 mm and GPC from 90 mm to 60 mm. However, GPC maintained better cohesion and pseudoplastic flow behaviour, making it more suitable for thin-section casting. GPC consistently outperformed OPC in terms of mechanical performance. At 20% PUF replacement, GPC exhibited a 26.84% higher 28-day compressive strength, and both systems remained structurally viable up to 15% PUF, maintaining compressive strength above 25 MPa and flexural strength above 3 MPa. GPC wall panels demonstrated 16-25% higher stiffness, 14-22% greater peak load capacity, and superior ductility, with gradual post-peak softening compared to OPC’s brittle failure. The optimum PUF replacement was found to be 15%, which balanced strength retention with 19-22% density reduction. Furthermore, failure modes in GPC transitioned from vertical splitting to edge-corner cracking, indicating an improved crack-bridging capacity. Overall, the findings confirm that PUF-based GPC wall panels offer a sustainable and lightweight alternative that is suitable for modern construction needs and has improved structural efficiency.