Tests and evaluation of structural concrete durability at Ningbo marine wharf
ZHAO Hui;ZHANG Ya-mei;MING Jing;Architectural Engineering Institute,Jinling Institute of Technology;School of Materials Science and Engineering,Southeast University;
In order to study the influence of environment factors on the structural concrete durability,the durability properties of concrete at different structural regions of the working platform of a marine wharf in Ningbo are tested.The test results show that the carbonation depth and the characteristic value and designed value of bar protective layer thickness change from high to low,namely those in the atmosphere zone are greater than those in the water level fluctuating zone,and those in the water level fluctuation zone are greater than those in the underwater zone.The change in the apparent chloride concentration and alkali content of the concrete is: that in the underwater zone is higher than that in the fluctuating water level zone and that in the fluctuating water level zone is higher than that in the atmosphere zone. In terms of the apparent chloride diffusion coefficients,the fluctuating water level zone is greater than the underwater zone and the underwater zone is greater than the atmosphere zone. Concrete in the atmosphere zone is much exposed to CO2,which results in deterioration of the protective layer thickness. The combined action of chloride ion with CO2erosion leads to deterioration of the protective layer thickness in the fluctuating water level zone. The limitation of operation time and bad environment lower the ability of reinforced protection,and a faster steel corrosion and the deterioration of the layer thickness can be found in the underwater zone.