Chloride penetration in RC-structures in marine environment – Long term assessment of a preventive hydrophobic treatment

Chloride ingress is one of the main causes of corrosion of the reinforcement in concrete structures, certainly for structures that are highly exposed to chlorides, such as off-shore or on-shore constructions in marine environment. This paper deals with the quay-wall of the new container terminal at Zeebrugge Harbor, Belgium, which is protected against chloride ingress by means of a water repellent agent immediately after construction in 1993 using an alkyltriethoxysilane, pre-evaluated in a preliminary research program. To judge the in site effectiveness of the hydrophobic agent as a water repellent treatment, three subsequent in site surveys have been conducted in 1996, 1998 and recently in 2005. Based on the cores drilled, the chloride profiles are determined as a function of time, both in a non-treated and treated location. The results are presented and discussed. Because of the long-term data sequence, the long-term effectiveness of the treatment can be assessed in an objective way.