Utilization of Wood Fibers as Secondary Reinforcement in Conventional Concrete Construction

Past applications of wood fibers in cement-based materials have been limited to the specialty market of thin cement panels. Synthetic fibers have recently gained tremendous popularity as secondary reinforcement in conventional concrete for shrinkage crack control. Concrete reinforcing fibers should provide high levels of slenderness ratio, elastic modulus, tensile and bond strengths, and fineness. Cellulose fibers either match or surpass synthetic fibers in all these attributes, and also cost less; however, they are difficult to disperse in concrete where processing involves limited mixing action and free water; cellulose fibers also damage the workability of fresh concrete. These processing problems can be attributed to the hydrogen bonding, high surface area and affinity for moisture of cellulose fibers. Out strategy is to adjust the hydrogen bonding potential, hydrophilic nature and surface roughness of pult fibers in order to resolve these processing problems while retaining the high reinforcement efficiency and cost-competitiveness of wood fibers. Phase I research assesses the viability of the approach through: 1) selection of effective means of enhancing pulp fiber dispersability and fresh mix workability; 2) refinement of fibers and optimization of the system to complement desirable processability with high reinforcement efficiency at competitive costs; and 3) competitive analysis of cellulose versus synthetic fibers as secondary reinforcement for concrete.