Accelerated Penetration Test And Service Life Prediction With Chloride Of Concrete Structure

Durability of concrete in civil engineering has become one of the mainly concerned issues in recent years. The durability and the service life prediction of concrete structures based on chloride ion penetration had been paid much attention by more and more people. However, the description of the chloride ion transmission in concrete and the service life prediction using Fick's law, Nernst-Planck equation or Nernst-Einstein equation was not applicable because of the effects of the characteristics of concrete, the chemical binding ability, the ionic interaction and the double electronic shell on concrete surface.There are several defects in the existed accelerated chloride ion penetration apparatus aiming at this issue. A multi-channels and variable-voltages chloride ion penetration apparatus was developed in this study. It has the following advantages: (1) The increased volumes of the cathode chamber and the anode chamber may minimize the temperature effect on the test results; (2) The corrosion resistant nano-electrodes were used; (3) Automatic data collection, 0~60V direct current source and 6 test channels were developed; (4) There was a chamber between the cathode chamber and the anode chamber to fix the concrete specimen, so the specimen and the apparatus were in the same conditions and the thickness of concrete samples was unlimited; (5) The current and the chloride ion concentration in solution could be recorded, and the reproducibility of the test results was quite satisfactory.The chloride ion penetration of the cement mortar was investigated after the specimens were curing in water for 28 days. The results show that the water to cement ratio (w/c) is the most important factor which affects the chloride ion penetration of cement mortar, and the chloride ion penetration of cement mortar increases with the increment of w/c. The chloride ion penetration of the cement mortar incorporated with fly ash is greater than that of the control cement mortar and increases with the increment of the fly ash. The chloride ion penetration of the cement mortar incorporated with slag is less than that of the control cement mortar when the slag replacement is 10%, 20% and 30%, respectively. However, the chloride ion penetration of the cement mortar is greater than that of the control...