Thermal and Mechanical Properties of Eco-Friendly Lightweight Concrete Based on Pine Resin and Recycled Expanded Glass Aggregate

The aim of this study is to develop an eco-friendly lightweight concrete that contains recycled expanded glass aggregate (EGA) and pine resin (PR) and to contribute to sustainable solutions for energy consumption, energy efficiency, and waste management in buildings. Waste EGA (2–4 and 4–8 mm) was sorted based on grain sizes and separately mixed with cement at 15%, 35%, 55%, and 75% ratios of the total volume. Pine resin was added into each mixture at 0.5% and 1% ratios of the total mixture (EGA + cement), and artificial micropores were created in order to enhance total porosity and produce specimens with superior thermal performance. Twenty-four combinations were produced from the specimens, and after they were dried at room temperature for 28 days, their thermal, physical, mechanical, and microstructure properties were analyzed. Results of the study indicated that some properties of the specimens significantly improved. As EGA grain size, ratio, and resin amount increased, density, thermal conductivity, compressive strength, modulus of elasticity, ultrasonic pulse velocity, and water absorption decreased, but porosity and abrasion loss increased. Notably, the water absorption ratios of the specimens remained below 30%, which is the critical value. Consequently, this study suggests that the developed lightweight concrete specimens have the potential to outperform traditional materials in various applications such as mortar, plaster, wall panels, brick or briquette works, and roof and floor concretes due to their superior insulation properties.