عنوان مقاله [English]
High-performance fiber cementitious composites are new materials in construction industry. Investigation into their behavioral characteristics needs experiments due to the lack of data. In this study, tensile, compressive and bending behavior of this material is examined using experimental tests.High-performance fiber reinforced cementitious composites (HPFRCC) have strain hardening response under straight tension after cracking. Numerous cracks are formed before the crack widening occurrence when these composites show hardening behavior. HPFRCC are basically integrated with two main components including fiber and mortar. These two ingredients are interactively affected due to interfacial bonding which develop a strong composite. The advantages of HPFRCC in comparison with normal and fiber reinforced concrete (FRC) are ductility, durability, and high-energy absorption capacity. In this paper, evaluation of strain hardening behavior in HPFRCC is conducted using straight tension and tensile strain-stress curve. Moreover, bending behavior, load-displacement curve, and toughness factor of this material are evaluated using four-point bending test, and the performance is compared with bending behavior of normal concrete. In these tests, three fiber types, including
hooped steel fiber, corrugated steel fiber, and poly propylene fiber, are used in the mortar separately and in combination with each other by volume percentage of 1.5\%. To achieve a proper strain hardening behavior, different mix ratios are investigated and the best mix design is determined. The results showed that all specimens mixed with fibers have strain hardening behavior accompanied by more cracks; consequently, the strength and strain of the HPFRCC specimens are increased significantly compared to those of normal concrete. The strength of HPFRCC specimens is between 5 to 8 times greater than that of normal concrete. In addition, the ultimate strains of the specimens are 70 to 100 times higher than that of normal concrete. Furthermore, toughness factor of HPFRCC specimens is 5 to 9 times higher than that of normal concrete. It is revealed that the mechanical properties of HPFRCCs have been considerably enhanced compared to normal concretes. HPFRCCs can be applied as an appropriate technique to restrain the reinforcement congestion, decrease the high value of transverse reinforcements at beam-column joints, and also improve the shear capacity and ductility of the members.