Reinforced cement sheet product containing wollastonite for reduced shrinkage

Abstract

A cement-wollastonite product consisting essentially of Portland cement binder in an amount of between about 40% and 90% by weight, and wollastonite in an amount of between about 10% and 60% by weight. The product may contain fibers in an amount of between about 1% and 15% by weight. If the product contains fibers other than asbestos and is to be formed on a Hatschek or other type of wet forming machine, it may contain clay in an amount of between about 2% and 15% by weight, and poly(ethylene oxide) homopolymer in an amount of between about 0.03% and 0.5% by weight. The product may also contain silica and/or filler in an amount of between about 10% and 40% by weight for replacing part of the wollastonite. The filler may be waste fiber-cement product or inert filler material.

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