Effect of fiber type and content on the performance of extruded wood fiber cement products

Abstract

This study presents the physical, mechanical, and durability characteristics of the extruded cement fiber products manufactured with various types of wood fibers. Four types of wood fiber cement products, one each produced with softwood, hardwood, recycled wood, and a blend of hard/softwood fibers were investigated in the experimental program. For each type of fiber mixtures, the effect of fiber content (fiber to cement ratio) was investigated at 5%, 10%, and 15% levels. These products were tested in unaged and aged conditions after exposure to accelerated aging effects. Test results showed decrease in bulk specific gravity and increase in water absorption capacity of the wood fiber cement composites with increase in fiber content. Considerable increase in flexural toughness was recorded with increase in fiber content for the softwood fiber products. After exposure to accelerated aging conditions comprising of freeze-thaw cycles, wet-dry cycles, saturation, and warm water exposure, the softwood fibers-based cement composite provided the highest level of flexural strength and stiffness. Furthermore, fiber cement composites having 10% fiber content retained a target flexural strength of 8–10 MPa besides showing good flexural stiffness after aging. Test results of this study help in identifying wood fiber reinforcement conditions which yield extruded fiber cement products with the balance of physical, mechanical, and durability characteristics suiting different building applications.