Microstructural Evolution and Physico-Mechanical Response of Cement-Bonded Fiberboards: A Comparative Study on Cement Type and Fiber Ratio

This study investigates the critical interplay between cement grade (32.5, 42.5, 52.5) and fiber/cement ratio (1/2 to 1/5) in determining the performance of cement-bonded fiberboards. Experimental results highlighted a fundamental trade-off: while reducing the fiber content significantly enhanced mechanical strength and moisture resistance, it naturally diminished thermal insulation capabilities. The analysis identified the 42.5 cement at a 1/4 ratio as the optimal formulation, offering the most effective balance between structural integrity and physical stability. To understand the mechanism behind this performance, the study employed multi-scale characterization using FTIR, XRD, and SEM. These analyses revealed that the superior properties of the optimal formulation stem from a denser hydration product network and improved fiber encapsulation. Specifically, the 42.5 cement facilitated a more robust Calcium-Silicate-Hydrate (C-S-H) gel formation compared to the 32.5 types, creating a stronger fiber-matrix interface. These findings provide a scientific basis for tailoring fiberboard production, demonstrating that material properties can be precisely engineered for either load-bearing or insulating applications.