Chloride penetration into concrete in marine environment - Part I: Main parameters affecting chloride penetration

The durability of concrete structures exposed to marine environment depends mainly on the ability of concrete to resist to chloride ingress. This complex phenomenon depends on many parameters related to the concrete properties and to the micro-environmental characteristics. This paper presents the results of an experimental study where fifty four 1.0 x 0.15 x 0.12 m concrete panels were exposed to marine environment for three to five years. A study of three concrete mixes in five different exposure conditions was conducted and the results show that the chloride penetration is strongly dependent on both the concrete quality and the exposure conditions. Both the diffusion coefficients D and the surface chloride concentration Cs derived from the chloride profiles show a clear time dependence. This effect has serious implications for long term predictions of chloride penetration, therefore if constant values of and Cs are assumed gross errors can be made.