Enhancing Gypsum Ceiling Sheets with Malt Waste: Optimal Composition for Strength and Insulation

Abstract

This study investigates the use of malt waste, a byproduct of the beer production process, as a bio-based additive in gypsum ceiling sheets to enhance mechanical performance while improving thermal insulation properties. Gypsum composite specimens were prepared by incorporating malt waste at weight ratios of 100:0, 90:10, 85:15, 80:20, 75:25, and 70:30, and the effects on density, thermal conductivity, and bending strength were systematically evaluated and compared with those of conventional gypsum boards complying with TIS 219-2009. The results show that increasing malt waste content led to a reduction in density from 1.16 g/cm³ for pure gypsum to 0.76 g/cm³ at a 70:30 ratio, representing a decrease of approximately 34.5%. Similarly, thermal conductivity decreased to a minimum value of 0.094 W/m·K, indicating improved insulation performance compared with conventional gypsum boards. However, the 85:15 gypsum-to-malt waste ratio demonstrated the optimum balance between thermal insulation and mechanical performance, achieving the highest longitudinal flexural force of 297.57 N and a thermal conductivity of 0.097 W/m·K. These findings highlight the potential of malt waste as a sustainable reinforcement material for the development of eco-friendly gypsum ceiling applications.