Mechanical Properties And Micro-Mechanism Of Synthetic Macro-Fiber Reinforced Concrete

Synthetic maro-fiber is a new type reinforcement material that appeared in the last of 20th century. When compared to steel fiber and synthetic micro-fiber, the synthetic macro-fiber offers a large number of advantages: (1) light; (2) evenly distributed; (3) erosion resistance; (4) obviously improves the impact resistance, flexural toughness, fatigue and seismic properties; (5) resistance for early crack; (6) prominent advantage in shotcrete. Synthetic macro-fiber reinforced concrete have been used for many years in USA, Japan and so on, and achieved remarkable effect, it provides a development orientation of cement matrix composites in the future.A series of tests are firstly conducted in this paper, and they are: (1) flexural test; (2) flexural impact test; (3) pull-out test; (4) uniaxial tension test; (5) seismic performance test; (6) fatigue test; (7) erosion resistance test; (8) mechanical properties tests of hybrid fiber reinforced concrete.According to analyze experimental data of flexural toughness test of synthetic macro-fiber reinforced concrete, based on ASTM and JSCE method, a new flexural toughness evaluating method is first proposed, it may well and truly reflect toughen and crack arrest of synthetic macro-fiber.In home and abroad, most of research works about impact performance of fiber reinforced concrete (FRC) are under compress, but members of practical structure are under flexural. New type drop weight flexural impact equipment is developed, which has important ideas for researching systematically flexural impact properties of FRC. Aiming at dispersion of impact experimental data is large, statistic analyses method is conducted, and it can reflected roundly impact properties of FRC.Pull-out test of flexible macro-fiber is conducted firstly, this paper is emphasized effects of fiber embedded length, cured times and matrix strength on bonding strength between synthetic macro-fiber and mortar. Based on the experimental observations, a new mechanical model for analysis of shaped flexible fiber is first developed, a good agreement is achieved between the predicted and the experiment results. It has good practical and academic value for research of interfacial bonding between shaped synthetic macro-fiber and matrix.For concrete consisting of hardened cement, aggregates, pore and micro-cracks of different sizes, reinforcing effects of only one type of fiber are limited, however,...