Study on the effect of sisal fiber on mortar with MSWI bottom ash sands: Strength performance and leaching behavior

The application of municipal solid waste incineration bottom ash (MSWI BA) as a potential alternative to natural sands in sustainable construction is limited by poor mechanical strength and contaminant leaching. To address this, this study proposes a novel and green strategy by incorporating sisal fibers (SF) into mortars containing MSWI BA sand. Results show that increasing MSWI BA content decreased mechanical strength due to higher porosity, while the plant fiber addition improved strength through a filler effect, consistent with Hirsch’s theoretical predictions. Environmentally, SF reduced the contaminant leachate, with chloride (Cl⁻) and Ba concentrations decreasing by approximately 50% and 35%, respectively, thereby meeting Dutch requirements for building materials and contributing to lowering CO₂ emissions. Economically, the incorporation of SF into MSWI BA mortars achieved higher cost-effectiveness. Overall, this work demonstrates a practical and sustainable approach for the large-scale substitution of natural sand with MSWI BA.