Patent ID: 7815841

Claim:
A method of manufacturing a fiber reinforced cement composite material, consisting of: providing unbleached cellulose fibers individualized to about 500 CSF; treating at least a portion of the cellulose fibers in solution with about 10% by fiber mass with one or more sizing agents in the presence of water or an organic solvent for about 1 hour at ambient temperature at 1 atm and 4% pulp consistency, wherein the sizing agent comprises a hydrophilic functional group and a hydrophobic functional group, wherein the hydrophilic group chemically bonds to at least some of the hydrophilic sites on inner and outer surfaces of the fibers to form sized fibers, wherein the sizing agent substantially blocks the hydrophilic sites, thereby reducing the fibers' affinity toward water; mixing about 8% by weight sized fibers with about 35% cementitious binder and about 57% ground silica to form a fiber cement mixture; forming the fiber cement mixture into a fiber cement article of a pre-selected shape and size; precuring the fiber cement article for about 8 hours at ambient temperature so as to form the fiber reinforced composite building material; and autoclaving the fiber cement article for about 12 hours at about 180° C.