Research On The Property Of High Durability Concrete In Bridge

Durability of concrete is a serious problem which must be faced in the field of road. The reliability of bridges depends on the durability of concrete to a great extend. Many roads and bridges failed at early age because of low durability of concrete. High durability concrete is a new concrete technology which takes durability and economy into consideration which can improves the concrete performance significantly. It is a new way for environment protection and continual development of roads and bridges construction.Considering the past research results, frost resistance of concrete using Portland cement, and the designed service life of 100 years of testing bridge, the control indexes of high durability concrete are defined in this paper. Mixture proportion of concrete used in pier column, coping, precast box beam and plate of bridge is designed based on the compact pile theory, and construction technique is studied also.The concrete used in testing bridge is monitored and some performance at definite age including compressive strength, splitting fensile strength, frost resistance, scaling frost resistance, chloride ion diffusion coefficient (DCl-), resistance of carbonization and pore structure by mercury porosimetry are tested. These performances are compared with that of concrete which designed by traditional method. The results show that mechanical properties of concrete designed by high durability concrete proportion and traditional method meet require ment at any age, however, frost resistance, scaling frost resistance, chloride ion diffusion coefficient (DCl-), resistance of carbonization and pore structure of the former are better than the latter, so high durability concrete is economic benefit.Polypropylene fiber reinforced concrete (PPFRC), steel fiber reinforced concrete (SFRC) and mixed fiber reinforced concrete used in plate of bridge are studied. The performances of concrete with different fiber content, such as compression strength, tension strength, splitting tensile strength, frost resistance, shrinkage, early shrinkage and chloride ion diffusion coefficient (DCl-) are studied. The result is that. mixing certain amount of fiber can improve...