Research on Durability of Bridge Fair-faced Concrete

According to the structural characteristics and service environment of bridge engineering, the durability design idea and technical approaches of bridge fair-faced concrete are put forwarded, and concrete with high working performances and good mechanical properties is prepared. The micro pore structure characteristic, volume deformation performance, chloride penetration resistance, anti-carbonation, antifreeze and sulphate resistance properties of the concrete were investigated. The research results show that bridge fair-faced concrete prepared had low gas content, relatively dense microstructure, excellent volume stability and outstanding durability. Autogenous shrinkage rate is less than 3.5×10^-4 and drying shrinkage rate is less than 4.0×10^-4 at the age of 28 days. Electric flux of C40 and C50 concrete are 819C and 779C respectively, and the carbonation depths are 2.3mm and 1.8mm respectively at the age of 56 days. After 300 times of freeze-thaw cycling, the quality loss of all test specimens are less than 1%, and the relative dynamic elastic modulus are greater than 95%. And the compressive strength corrosion coefficient of the specimens are above 85% at 150 times of wet-dry cycling.