Speaker
Description
Energy performance in buildings is a critical issue for researchers and engineers, who are increasingly focused on developing innovative materials and techniques to enhance thermal efficiency. Intelligent and sustainable design plays a pivotal role in reducing energy consumption, contributing to the decarbonization of human activities and mitigating climate change.
In parallel, the reuse of construction and demolition waste (CDW) and of recycled polymers in building materials has become an essential strategy to minimize environmental impact while improving material properties. This approach ensures thermal and hygrometric comfort, promotes energy savings, and supports circular economy principles.
This experimental study investigates cementitious mixtures through two complementary strategies: (i) partial replacement of Portland cement with supplementary cementitious materials (SCMs), specifically natural pozzolan, and (ii) substitution of natural aggregates with lightweight aggregates (LWAs), including polymer waste and selected CDW. Several mix designs were prepared, starting with a reference specimen without any substitution, followed by mixes incorporating Aerated Autoclaved Concrete waste and rubber aggregates from End-of-Life Tires (ELTs) as sand replacements. Substitution ratios ranged from 0% to 100% by volume, enabling the development of innovative and eco-friendly mortar composites.
Thermophysical performance was assessed experimentally through thermal conductivity and thermal diffusivity measurements. The experimental setup for thermal diffusivity testing included a 1 kW halogen lamp and an Avio 550 infrared thermal imaging camera, ensuring accurate monitoring of temperature evolution during heating.
Results demonstrated the feasibility of incorporating up to 100% AAC waste by volume for mortar production. Significant improvements in thermal insulation were observed in mortars containing AAC and ELT rubber. Specifically, a 35% volume substitution of natural pozzolan for traditional binder was identified as the optimal incorporation rate for designing eco-efficient mortars. Furthermore, natural aggregates can be replaced up to 100% by volume with AAC or ELT rubber, or a combination thereof. In these cases, thermal conductivity decreased by approximately 50%, while thermal diffusivity dropped by about 60%. Conversely, binder replacement alone produced only marginal improvements, whereas aggregate substitution proved highly effective in enhancing thermal performance.
Overall, these findings confirm that LWAs—particularly recycled waste materials—represent a promising strategy for producing thermally insulating mortars with low environmental impact at an industrial scale. SCMs, while beneficial for sustainability, have limited influence on thermal properties compared to aggregate substitution. This research highlights the potential of combining waste reuse with advanced material design to improve building energy efficiency, reduce carbon footprint, and support sustainable construction practices.
