Deterioration assessment model for splash zone of marine concrete structures

Concrete exposed to splash zone in partially submerged concrete structures deteriorates rapidly due to reasons such as wetting-drying cycles, the impact of waterborne materials, bio-deterioration, chloride and sulphate attacks. Existing condition assessment and rating systems do not adhere to the interrelation between different performance attributes of splash zones and these models are extremely subjective to the performance of the evaluator. The objectives of this study are to evaluate the effectiveness of parameters that deteriorate marine concrete structures and to develop a new model to predict the rate of deterioration of splash zone in marine concrete structures. The fuzzy Analytical Hierarchy Process (FAHP) was used to develop the model to predict the rate of deterioration. Here, local factors were grouped under five primary parameters as visual inspection, water quality, casual factors, Non-Destructive Tests (NDTs) and crack details. Data relevant to 15 structures were gathered by visual inspection, laboratory and field experiments to validate the proposed model. Attributes of water quality achieved the highest priority for the deterioration of the slash zone of marine concrete structures. Further, numerical values were assigned to this rating model to avoid ambiguity and vagueness of linguistic descriptors in existing rating systems. Finally, the model developed in this study can be used to evaluate the deterioration percentage of the splash zone in structures and according to that appropriate retrofitting and repair work can be done.