When reinforced concrete structures suffer damage due to structural, environmental, and material factors, they have to face consequences such as cracks, sagging, and lowered strength, usability, durability, and safety. In South Korea, there has been a huge increase of maintenance demand for deteriorated national infrastructure in recent years. The focus is also shifting from new investment to repair and reinforcement. Used in the repair of structures, polymer composites have superior mechanical properties to the common cement mortar and are considerably useful as repair materials in inferior environments. Most of previous studies in the field, however, focused on polymer cement concrete (PCC) with a small number of researches on polymer concrete (PC). This study thus developed a polymer mainly made of polyurea and epoxy resin, analyzed its mechanical properties according to the curing temperature, conducted a bending experiment with RC beams repaired with the developed polymer mortar at various depths on the tension and compression axis, and assessed its influence on flexural behavior. Isocyanate, a PUER material, increased in reactivity, was fast with hardening, and improved in such physical properties as tension strength and hardness when its NCO (%) content and molecular weight were high. When amine was used as a hardening agent, its reactivity was fast. When the content of polyol increased, its hardening time increased with its mechanical properties dropping. When 5% of epoxy resin was added to the hardening agent, proper hardening time and mechanical properties were guaranteed. As for the mechanical properties of RH-PUERM, it recorded bending, compression, and direct tension strength of 20, 30, and 10MPa or higher, respectively, after 24 hours across all the curing temperatures, which indicates that the curing temperature did not have much impact on the manifestation of strength. The bond strength results show that it penetrated into the matrix and achieved complete bond. As for the mechanical properties of HD-PUERM, it manifested its strength normally at the room temperature and needed 72 hours of curing or longer at the curing temperature of 0℃ or lower. Its bond performance was guaranteed even at low temperature by ensuring enough curing for 168 hours. Its strength was low at the curing temperature of -20℃, which means that its application to winter construction will be difficult. RH-PUER mortar was planned as a part of preliminary study for the application to RC structure repair. The study reviewed the flexural behavior of beam structures that had the tensile or compressive zone repaired in the RC structure. It then proposed an analytical model to predict the flexural behavior of RC beams, conducted a test, and compared the test results with those of analytical model. In the beams whose compressive zone was repaired with RH-PUERM, the tensile zone showed brittle behavior regardless of section depth when the repair was done with 30% of section depth or higher. Those findings indicate that the compressive zone should be repaired at 30% of section depth or lower and that the tensile zone will be difficult for repair due to its brittle behavior regardless of section depth. There was a transition of destruction to brittleness according to the increasing thickness of polymer mortar in all the beams that were repaired in the compressive and tensile zone, which raises a need to set the repair thickness properly to prevent any extreme changes to the polymer mortar in extreme conditions and thus guarantee appropriate malleability. The analytical model proposed through the interpretation of flexural behavior in the RC beams repaired with polymer mortar was capable of predicting the bending strength of beams repaired with RH-PUERM. Its analytical ratio was mean 0.81 in the experiments on displacement under maximum load, which indicates for the underestimation of displacement in the analytical model. Non-linear interpretations based on the two-dimensional frame elements and fiber model made proper predictions of flexural behavior of RC materials repaired with polymer mortar.