Patent ID: 7169224

Claim:
A process for increasing strain hardening in fiber-reinforced cementitious composite containing natural flaws, comprising: a) selecting a hydraulically settable matrix composition containing matrix interactive fibers; b) adding to said composition, crack-initiating, void-forming particles, said particles forming voids having a size of from 0.5 mm to 5 mm, said voids present in an amount of about 1 volume percent to about 20 volume percent; c) adding water to a) and b) to form a setting composition, and allowing said setting composition to set to a fiber-reinforced cementitious composite, wherein said volume percent is based on the total volume of said fiber-reinforced cementitious composite, and wherein components a), b) and c) may be admixed in any order, said hydraulically settable matrix composition, when hydraulically set by addition of water but without void-forming particles b), having a density of about 1.95 g/cm 3 to 2.4 g/cm 3 .