In this study, the compatibility of polymer modified repair mortar and
substrate concrete was investigated in three stages. First stage includes studying the individual properties of polymer and conventional repair materials, and also two types of concrete, such as compressive strength, split tensile strength, and flexural strength using standard ASTM test procedure. Second stage includes evaluating the bond strength of composite cylinder for different combinations of repair materials
and substrate concrete. Third stage includes investigating the compatibility using a composite beam of repair material and substrate concrete under third point loading. The experimental results show that the compressive strength, split tensile strength and flexural strength is not a crucial factors for the success of concrete repair system. While bond strength tests are provide strong indication about the
compatibility. The bond strength of S.B.R polymer material produced by Al- Khaleej Company was not strong enough to be recommended to use for concrete repairing systems.