In this experiment, tire rubber powder with 5.3% of sieve residue on mesh 40 is utilized in concrete. Rubber concrete mixture samples are prepared with three kinds of rubber powder, untreated, Na treated and Si pre-treated. The Na-treated powder and Si-treated powder are surface treated with saturated sodium hydroxide aqueous solution and silane coupling agent, respectively. The effects of this treatment are assessed by investigating the properties of the rubber concrete and the bonding at the interfaces between the powder and the concrete matrix. The results show that the compressive strength and flexural strength of the concrete mixture samples are reduced with the addition of rubber powder whether treated or not. The impact toughness and strain are higher than those of control samples due to the fact that amounts of energy are absorbed by the rubber powder. Further, it is in the samples prepared with Si-treated rubber powder where the two properties (impact toughness and strain) are highest, a result attributable to better bonding between the powder and the concrete matrix. Further investigation of the bonding at the interfaces between the rubber powder and the concrete matrix is carried out by the Fourier transform infrared spectroscopy and the environmental scanning electron microscope. Hydrogen and covalent bonds are found to have formed in the interface regions between the Si-treated rubber and the concrete matrix. The results indicate that the silane works as a 'bridge' in these regions and bonds the rubber and concrete more firmly by two types of bonds.