Improvements in concrete technology enabled engineers to produce special concretes with high strengths. However, as known high strength concrete exhibits a very brittle behavior. Many researchers have tried to change this brittle failure mode to a ductile type failure by adding various types of fibers in to the concrete. Consequently, different types of concrete with fibers were developed such as Fiber Reinforced Cementitious Composites (FRCC), Fiber Reinforced Concrete (FRC), Ductile Fiber Reinforced Cementitious Composites (DFRCC), High Performance Fiber Reinforced Cementitious Composites (HPFRCC) etc. Many researches on this topic have showed that fibers increased the ductility and energy dissipation capacity öf the concrete members. In this research; the main goal is to develop a material that can be used to improve the behavior of reinforced concrete members built with low-strength concrete (fj^lO MPa, in which f'c is the compres-sive strength of the concrete) under seismic loads. HPFRCC may be used for this purpose. The main idea is to produce precast thin panels made of HPFRCC and retrofitting reinforced concrete members by attaching these panels to the surface of the reinforced concrete members. It is clear that as the mechanical properties of the HPFRCC improve, the effectiveness of HPFRCC panels in retrofitting will also increase. In order to investigate the mechanical characteristics of the HPFRCC, two series of experimental studies were carried out. The first series of tests included compression tests of 27 standard cylinder specimens and tension tests of 54 standard splitting disc specimens. For compression tests nine sets and for each set three identical cylinder specimens were produced. For tension tests six standard splitting disc specimens were produced for each of nine sets. The diameter of cylinder is 150 mm and height is 300 mm. The diameter and height of the standard splitting discs are 150 and 60 mm, respectively. In the tests of the first series, the testing parameters included hot water curing, decomposition of steel fibers before adding them into mixture, corrosion and the amount of steel fibers. Second series of tests included flexural tests of beams with dimensions of 100x100x500 mm. The only parameter in beam tests is the amount of steel fibers. Three different mixtures and for each mixture there identical beams were produced. Compression tests of standard cylinder specimens were carried out either under static monotonic or cyclic axial compression loads by using Amsler machine with 5000 kN loading capacity. Two linear displacement transducers were used to measure axial deformations. To determine the elastic modulus, the specimens were subjected to one loading and unloading cycle in the linear range of the stress-strain curve before the full test and then elastic modulus was obtained from the slope of the linear best-fit line. During loading and unloading cycle axial deformations were measured both in the full length (~300 mm) and in 150 mm at midheight of the specimens. For the tests of standard disc specimens a 1000 kN capacity Amsler machine was used. For the beam tests 100 kN capacity Instron 5500R machine was used. Fracture energy, bending strength and toughness of the specimens were obtained from load-displacement curves. Three point loading tests were carried out for beams and loading rates were 0.05 mm/minute and 0.1 mm/minute for the ascending and descending branch of load-displacement curves, respectively. The displacements were measured at the middle point of the beams. In the tests of specimens without steel fibers the loading rate was 0.0175 mm/minute during the entire test. The maximum target displacement was 10 mm, which corresponded to 2.5% drift ratio for specimens with steel fibers. For the tests of specimens without steel fibers, there was no maximum target displacement since the behavior was very brittle. The brittle failures occurred around 0.03% drift ratio, As results of the compression and splitting tension tests, the hot water curing was found to increase the tensile strength of concrete significantly. It was also found that small amount of the corrosion of steel fibers have no effect on the mechanical characteristics. It was clearly seen that as the amount of steel fibers increased, the mechanical properties such as tensile strength, toughness and ductility also increased while compressive strength and elastic modulus did not change. Results of beam tests showed that the bending strength and toughness increased significantly with increasing amount of steel fibers.