Validation of models and test methods for assessment of durability of concrete structures in the road environment
This report presents the results from validation of models and test methods for assessment of durability of concrete structures exposed in Swedish road environment. In the past years a number of models for durability design of concrete structures have been suggested by relevant organisations or international committees. It is necessary to validate these models against long-term field data for their applicability with respect to exposure climate in order to satisfactorily use the models in the durability design and redesign of concrete structures. In this study, various potential models for concrete resistance to chloride ingress, carbonation and frost attack were compiled and the sensitive input parameters that affect the modelling results were mathematically analyzed. Three models including the simple ERFC, the DuraCrete and the ClinConc, for prediction of chloride ingress were evaluated using the infield data collected from both the field exposure site after over 10 years exposure and the real road bridges of 25-30 years old. A physicochemical model for prediction of carbonation depth was evaluated using the infield data collected from the field exposure site after 11 years exposure and the limited data from the real structures with the age of 7-13 years. The results from different standard test methods including the newly standardised prEN/TS 12390-11 for chloride diffusivity were compared. For the modelling of frost attack, some test procedures for measurement of critical saturation degree and water absorption curves including the pump effect were suggested. Based on the results, recommendations as guidelines for practical application of test methods and models in durability design of concrete structures were suggested.