Microstructure of extruded cement-bonded fiberboard

The microstructure of cement-bonded fiberboard manufactured by extrusion process was studied using scanning electron microscope (SEM). Comparison between extruded and cast fiberboard revealed that the extruded products were better in strength, stiffness, toughness, fiber distribution, fiber orientation, and bond of fiber with matrix, even in the presence of a higher percent air voids. The dominant component in extruded fiberboard was the type of fiber. Extrusion was capable of incorporating both hydrophilic and hydrophobic fibers into fiberboard production. It was found the sand content had significant effect on toughness. The more the sand added, the less the toughness. Fiber dispersion seemed not to be critical. Fiberboard made by nondispersive mixing exhibited satisfactory performance. Accordingly, the mixing time and energy in extrusion production could therefore be reduced.