Evaluation of thermal performance in green roofs using recycled construction waste sand as substrate

Fecha de publicación: 01/02/2025
Fuente: Green Extration Byproduct
Abstract
Rapid urbanization has exacerbated climatic imbalances, including the urban heat island effect, and rising regional temperatures. Green roofs, which combine multiple layers of vegetative cover over a structural base, offer an ecological solution. This study investigates the potential of incorporating recycled construction and demolition waste (CDW) into green roofs to improve thermal efficiency; CDW, more specifically the byproduct of its recycling process, commonly referred to as ‘recycled sand’, contains a mixture of concrete and ceramic fragments. The study was conducted in Cascavel, S Brazil. The research compared green roofs made from recycled materials like concrete and ceramic fragments with traditional roofing. Various proportions of recycled sand and clay soil were tested in the substrates. Temperature analysis was carried out under both natural and humid conditions to evaluate thermal performance. The substrates containing recycled sand enhanced thermal efficiency, thus reducing internal temperatures by up to 3.4 °C on hot days. Additionally, sandy substrates retained heat better in colder periods but performed less efficiently when saturated. This study demonstrates the viability of using CDW to improve the thermal and energy performance of green roofs, particularly in hot climates.