Research On Chloride Ion Concentration Field Of Concrete Under Coupling Impact Of Temperature And Humidity

The chloride ion penetration led to rebar corrosion. It was the main factor of concrete structure damage in marine, west saline and saline soilenvironment. The erosion process was not only affected by the material performance of material, also affected by theexternal environment, especially the external temperature and humidity environment. In order to reveal the response of temperature and humidity and the influence of it on chloride ion transfer, heating, cooling and capillary suction salt, thermal conductivity test were conducted and comprehensively analyzed under the different temperature and humidity environment. The following conclusions can be obtained:(1)With the increase of concrete IRH, heat transfer rate accelerated. The close location of distance from the heat source, the thermal response accelerated and the time needed in the process of heating and cooling gradually reduced.(2) The close location of distance from the surface of water absorption, the increase speed of humidity was fastet and the final humidity value was bigger. With the increase of concrete IRH, the time needed that concrete reached equilibrium reduceded.(3) With the increase of environment temperature, the capillary water quantity and the absorption coefficent gradually increased and the changing relationship of capillary coefficient and temperature conformed with the Arrhenius equation. With the increase of IRH, the water quantity gradually decreased and the absorption coefficient decreased linearly with increase of humidity.(4) The moisture diffusion coefficient of concrete increased with the increse of temperature. The thermal conductivity increased with the IRH and age of concrete. What’s more, within 28 days it increased more quickly and after 28 days it became slow.(5) The transmission coefficient of chloride ions linearly decreased with the imcrease of concrete IRH. With the increase of external temperature, the transmission coefficient gradually increased and the changing relationship of transmission coefficient and temperature conformed with the Arrhenius equation.(6) With the increase of dosage of fly ash, the capillary water quantity and the absorption coefficient gradually decreased as a whole. With the increase of dosage of mineral powder, the water quantity gradually decreased. However, when the dosage reached 50%, the water quantity presented to slightly increase trend with the increase of dosage.(7) With regard to the LF50 concrete speciman blending with fly ash and mineral powder, the thermal conductivity, the thermal response speed, the increase speed of humidity, the moisture diffusion coefficient and the transport coefficient of chloride ion was less than L50 concrete. It led to the decrease of chlorine ion permeability.