Effect of hybrid fiber reinforcement on the cracking process in fiber reinforced cementitious composites

摘要

The simultaneous use of different types of fibers as reinforcement in cementitious matrix composites is typically motivated by the underlying principle ofa multi-scale nature of the cracking processes in fiber reinforced cementitiouscomposites. It has been hypothesized that while undergoing tensile deformations in the composite, the fibers with different geometrical and mechanical properties restrain the propagation and further development of crackingat different scales from the micro- to the macro- scale. The optimized design of the fiber reinforcing systems requires the objective assessment of thecontribution of each type of fiber to the overall tensile response. Possiblesynergistic effects resulting from particular combinations of fibers need tobe clearly identified. In the present study, the evaluation of the responseof different fiber reinforced cementitious composite materials is carried outby assessing directly their tensile stress-crack opening behavior. The effi-ciency of hybrid fiber reinforcements and the multi-scale nature of cracking processes are discussed based on the experimental results obtained, as wellas the micro-mechanisms underlying the contribution of different fibers tobridge cracks resulting from tensile loading.