Toughening in cement based composites .2. Fiber reinforced cementitious composites

This paper reviews the mechanisms of toughening in fiber reinforced cement based composites. Reference is made to frontal, crack tip and wake processes, and estimates of contributions to composite toughness of the individual mechanisms are included It is emphasized that the wake processes, which dominate the inelastic energy absorption during fracture development in these materials, can be well characterized by tensile stress vs crack opening relationships. The fiber/matrix interface debonding energy, not usually important in fiber reinforced concrete, is shown to play an important role in new straining-hardening engineered cementitious composites as an additional frontal process with significant energy absorption capacity thus giving rise to a cement based material with extremely high damage tolerance. (C) 1996 Elsevier Science Limited.