Chloride assessment in structures. Influences of sampling and test location

Abstract A reliable measurement of chloride content profile is a key parameter in condition assessment and service life prediction of existing marine structures. The variability associated with the measurement and heterogeneity of concrete made it an endless study subject. The article presents the experimental results of the chloride content of concrete obtained by two methodologies. These results are compared and discussed and recommendations are made for defining the sampling plan. Grinding and Cutting/Crushing methods were applied in a laboratory based study and performed on an existing coastal structure. Significant differences were observed in the results obtained by different sampling methodologies near the concrete exposure surface, these differences tending to be null in depth. Due to “wall effect”, at concrete surface, the chloride content by mass of cement will be higher than the real one, if the calculations do not account for the higher cement paste proportion of this zone.