Patent ID: 7722964

Claim:
A fiber reinforced cement board having an absolute dry specific gravity of not less than 1.20 and not more than 1.30 and comprising the following raw materials: not less than 28% by mass and not more than 32% by mass of a hydraulic portland cement, not less than 54% by mass and not more than 58% by mass of a siliceous material, not less than 8% by mass and not more than 12% by mass of a woody reinforcement, not less than 2% by mass and not more than 5% by mass of mica, and not less than 0.5% by mass and not more than 1.25% by mass of a polyvinyl alcohol resin, wherein the siliceous material comprises fly ash and silica fume, and the woody reinforcement comprises needle leaves tree unbleached kraft pulp and/or needle leaves tree bleached kraft pulp and used paper, wherein the fly ash contains 50% to 70% by mass of SiO 2 , the silica fume is contained in an amount of not less than 3% by mass and not more than 7% by mass of the siliceous material, and contains 97% by mass or more of SiO 2 , the used paper is contained in an amount of not less than 20% by mass and not more than 50% by mass of the woody reinforcement, and the siliceous material and the portland cement contains CaO and SiO 2 at from 30:70 to 40:60 of a mass ratio CaO:SiO 2 .