Impact of marine environment on concrete buildings: Example of Libya Al-Zawiya College of Engineering

The aim of this study is to determine the causes and effects of physical and chemical damages, especially carbonation-induced reinforcement corrosion, observed in the reinforced concrete structure of Al-Zawiya Engineering Faculty, Libya. Considering the effects of regional climate and environmental conditions, carbonation process and reinforcement corrosion in reinforced concrete structures exposed to marine environment were evaluated. In experimental studies, carbonation depths were determined by phenolphthalein indicator method and the durability of concrete under different relative humidity, temperature and CO₂ concentrations were examined. Experimental results revealed that there is an inversely proportional relationship between carbonation depth and concrete compressive strength. Carbonation depth reached up to 75 mm in some columns. This situation indicates that the passive protective layer is lost and there is a risk of reinforcement corrosion. Chloride ion permeability was found to be close to the limit values. On-site rebound hammer and ultrasonic pulse velocity tests showed that concrete strength was heterogeneous and generally low. Structural analyzes were performed with ETABS 2018 software and it was determined that the bearing capacities of the slabs were sufficient, but the moment and shear strengths of some elements such as B17 coded beam and C22 coded column were insufficient. As a result, although there is no widespread strength deficiency in the existing building stock, it has been determined that local weak links may negatively affect the overall performance of the structure. In this context, reinforced concrete sheathing is envisaged for the deficient elements (B17 and C22).