Artificial Polymer Lightweight Aggregate Concrete With Coal Fly Ash for Biomedical Infrastructure: Mechanical, Physical, and Microstructural Investigation

Abstract

Aggregates constitute ~60%–80% of concrete volume and play a crucial role in determining its mechanical and durability properties. In the context of sustainable construction, artificial aggregates derived from industrial by-products are gaining prominence as environmentally responsible alternatives to natural aggregates. This study presents the development and performance evaluation of a novel lightweight concrete incorporating artificial polymer lightweight aggregate synthesized from coal fly ash (CFA), epoxy resin, and a hardener in varying CFA-to-resin ratios (70:30, 74:26, and 80:20 by weight). The proposed mix design aims to address the increasing demand for lightweight, durable, and sustainable materials suitable for biomedical infrastructure applications, which require enhanced thermal insulation, fire resistance, and seismic performance. Concrete mixtures were designed to achieve target compressive strengths of 17.5, 20, and 30 MPa, with both lightweight (BR series) and normal weight (BN series) concrete formulations evaluated. Results demonstrated that the incorporation of polymer lightweight aggregates reduced the bulk density of concrete by up to 15.36%, while meeting or exceeding the required compressive strength thresholds for BR_17.5 and BR_20 mixtures. Although the BR_30 mix did not meet the target strength, polymer lightweight aggregate-based concrete exhibited significantly improved flexural strength (up to 60.57% higher than conventional mixes) and enhanced chemical durability when exposed to acidic and saline environments. However, its resistance to elevated temperatures was lower compared to that of conventional concrete. The findings suggest that polymer lightweight aggregate concrete offers a promising sustainable material solution for biomedical infrastructure and other applications demanding lightweight, durable, and thermally efficient construction materials. The utilization of industrial waste in polymer lightweight aggregate production not only contributes to environmental conservation but also advances the development of next-generation building materials aligned with circular economy principles.