Preliminary study of life cycle cost of preventive measures and repair options for corrosion in concrete infrastructurecorrosion in concrete infrastructure

Abstract

Maintenance costs of reinforced concrete infrastructure (bridges, tunnels, harbours, parking structures) are increasing due to aging of structures under aggressive exposure. Corrosion of reinforcement due to chloride ingress is the main problem for existing structures in marine and de-icing salt environments. Corrosion cannot be ruled out completely for new infrastructure, even with today's emphasis on design for long service life (e.g. 100 years), a.o. due to local effects such as leakage of joints; consequently, repairs may be necessary. This study reports on total life cost calculations for various options to prevent or remediate corrosion damage in an example bridge which is exposed to de-icing salts, locally aggravated by leakage of expansion joints. Scenarios were developed to predict - the occurrence of corrosion damage in the joint areas, - total life cycle cost (LCC) effects of using stainless steel reinforcement, (repeated) hydrophobic treatment and cathodic prevention in the joint areas, - cost effects of conventional concrete repair and cathodic protection in the joint areas, depending on the working life of these corrective measures. Summarising the preliminary results, using stainless steel reinforcement and (repeated) hydrophobic treatment of concrete in the endangered areas is surprisingly economic. Furthermore, the working life of conventional repairs and cathodic protection are major parameters affecting the total life costs. A simple tool was developed for predicting the total life costs depending on working life and costs of various preventive and corrective measures.