Mechanical and thermal properties of recycled aggregate concrete reinforced with date palm fibers

Concrete, widely used in construction for its affordability and ease of preparation, contributes significantly to construction and demolition waste, making up 30% of global waste. Incorporating recycled aggregates and natural fibres into concrete enhances its mechanical performance, reduces environmental impact, and promotes sustainable, cost-effective construction practices. This paper evaluates the mechanical and thermal properties of recycled concrete reinforced with date palm fibres, focusing on their effects on compressive strength, flexural tensile strength and thermal conductivity. The research aims to enhance recycled concrete’s performance and promote sustainable construction practices by optimising mix composition and incorporating natural fibres like date palms. Concrete mixtures were designed with varying recycled aggregate substitutions (10%-50% and 100%), fibre additions (1%-4%), and combined modifications of fibres and recycled aggregates (10%-30% RA and 1%-3% DPF). A superplasticizer and a modified two-stage mixing method were used to optimize the concrete’s properties. Tests were conducted to evaluate density, water absorption, compressive and flexural strength, and thermal conductivity using the hot wire method. The results indicate that increasing the replacement of recycled aggregates and fibre content reduces concrete density, increases water absorption, and affects compressive, flexural, and thermal properties. However, optimal fibre content (2%) improves mechanical and thermal performance, especially at moderate replacement levels.