Thermally treated granite slurry waste as a mitigating agent for sisal fiber mineralization in fiber‐cement composites

Abstract This study explores the use of thermally treated granite slurry waste to mitigate the mineralization of sisal fibers in fiber‐cement composites. Granite waste was thermally treated at 600°C and 900°C, and the treated materials were analyzed using X‐ray fluorescence (XRF), Fourier transform infrared spectroscopy (FTIR), and thermogravimetric analysis (TGA). Sisal fibers, alkali‐treated with 1.7% NaOH, were incorporated into fiber‐cement composites, where 15% and 30% of the cement was replaced by treated and untreated granite. Composites with 15% of granite treated at 600°C and 900°C showed improvements in compressive strength of up to 12% and 18%, respectively, compared to the control. The flexural strength increased by 10% with 15% granite treated at 900°C. However, the untreated granite at 30% replacement increased porosity by 25% and water absorption by 18%, negatively affecting the mechanical properties. Aging tests showed a 40% loss in compressive strength, while composites with 30% granite treated at 900°C maintained their flexural strength, making them more durable. These findings highlight the potential of thermally treated granite waste to enhance the sustainability and performance of fiber‐cement composites in construction.