Rubber particles of different sizes were used to replace sand in the concrete which was exposed to workability test, uniaxial compression test, water permeability test, chloride penetration resistance test and freeze-thaw test. The results demonstrate that the fluidity of the crumb rubber concrete is minimized at the rubber particle sizes from 0. 63 to 1. 25 mm. The compressive strength of the concrete degrades as the rubber particle size decreases, while the introduction of small rubber particles has a positive effect on the concrete integrity. There exists an optimized particle size in the range from 0. 165 to 0. 315 mm, in which the electric flux, seepage height, mass loss rate and relative dynamic elastic modulus loss rate are 53. 15%, 52. 35%, 16. 35% and 51. 79% respectively of those for conventional concrete. Additionally, the prepared simply supported beam of crumb rubber concrete according to the ratio for optimized durability has a crack initiation load higher than that of a simply supported beam made of conventional reinforced concrete, but its ultimate load is 6. 10% lower than that of the latter.