Development of 3-D predictive ageing simulations of reinforced concrete port structures

The aim of this research is to formulate an advanced computer model for predicting the deterioration of marine reinforced concrete (RC) structures due to corrosion of steel reinforcement. This research is a part of the larger Linkage Project LP0883290 which is co-funded by the Australian Research Council (ARC), Geelong Port, Sydney Ports and AECOM Ltd. Chloride-induced corrosion of internal steel reinforcement is one of the major causes of concrete premature deterioration which incur significant ongoing costs to repair and replace the affected infrastructure. Despite increased research efforts worldwide to predict damage propagation over the years, knowledge gaps remain and existing models still cannot satisfactorily produce outputs which match with the damage observed in field marine structures that are located in corrosive seawater tidal, splash, and aerosol spray conditions. A 3-D Finite Element (FEM) computer model was developed to simulate damage propagation in RC structures resulting from reinforcement corrosion. It addresses the limitations of the existing models by incorporating algorithms for predicting dynamic (time-variant) corrosion rate and simulating non-uniform distribution of rust products around the reinforcement bar. The FEM was also programmed so that the environmental factor inputs can be varied along the 3rd dimension of the structure, thereby allowing the spatial variation of damage in 3-D to be simulated. The FEM can provide visual outputs for the development of corrosion-induced cracks over time and can be used to predict the type of damage and the time of damage occurrence within the concrete cover zone. The 3-D FEM was calibrated against published experimental data in the literature and against port data collected from field marine structures. It was found that the 3-D FEM damage predictions matched closely with the damage published in the literature and the damage observed in field structures. The 3-D FEM was used to analyse a wide range of corrosion scenarios involving different structural geometries, material properties and environmental exposures. The analysis results were used to formulate damage maps and regression models, which can be used by port asset managers who may not have the expertise to use the FEM to predict the damage propagation in RC structures. The key outcomes of this research have improved the understanding of concrete deterioration behaviour by providing new capabilities to predict the location, time of occurrence, type and degree of damage in field marine RC structures. This enhanced modelling allows port asset managers to make better decisions regarding the timing and method of repair and/or rehabilitation over the life cycle.