Research On Durability Of Reinforced Concrete Member With ECC As Concrete Cover

Corrosion of the reinforcement steel ususlly occured in reinforcement concrete structures under chloride environment,therefore the service safety and service life of these structures would be reduced.The ECC material can effectively improve the durability of the structure due to its remarkable anti-cracking ability.In order to verify the improvement effect of the ECC for the durability of reinforced concrete structures,9 reinforced concrete beam specimens and 6 slab specimens were designed.Accelerated electrochemical corrosion test and four-point bending test were carried out to the specimens.The durability,damage process,load and deformation capacity of the specimens were compared with each other.It was discussed the calculation method of the bending capacity of each specimen after durability damage.The seismic behavior of reinforced concrete piers retrofit with ECC was studied by numerical analysis method.The main work and conclusions are as follows:1.The durability test and bending test results of the 9 beam specimens showed that the ECC as the protective layer can improve the flexural bearing capacity of the specimen and enhance the resistance of the specimen to chloride corrosion.The durability of the test specimens with 50 mm ECC cover was better than the durability of the test specimens with an ECC thickness of 25 mm.However,it should be noted that the ECC and the concrete interface were prone to cracking during the durability test,which was harmful for the durability of the test specimens.2.The durability test and bending test results of the completed 6 slab specimens showed that after the same corrosion time,the bearing capacity and bending stiffness of the specimens with ECC as the protective layer were significantly larger than those of ordinary reinforced concrete slabs.ECC could improve the resistance of reinforced concrete slabs to chloride corrosion.3.The flexural capacity of each beam and slab specimen was cauculateed and compared with test results It was found that there was some deviation between the calculated value and test results.4.The numerical analysis was carried out by ZeusNL software to study the seismic behavior of ECC retrofit reinforced concrete bridge piers.The seismic performance of ordinary reinforced concrete bridge piers and ECC retrofit concrete bridge piers was compared.It was found that ECC can significantly improve the seismic performanceof reinforced concrete piers.