A Simplified Micromechanical Model of Compressive Strength of Fiber-Reinforced Cementitious Composites

A micromechanical model is constructed for the compressive strength of fiber-reinforced cementitious composites (FRCs). This model is based on the classical models of compressive failure of brittle solids in which sliding microcracks induce wing-crack growth under compression loads. The concept of increased microcrack sliding resistance and wing-crack growth retardation associated with fiber bridging is exploited to produce a strengthening effect of fibers in composite strength. The concept of defect introduction associated with fiber volume fraction is included to produce a composite strength degradation. The combined effect results in composite compressive strength which increases initially and subsequently drops with increasing fiber content, as has been observed in FRCs reinforced with a variety of fibers.