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Study on the Accuracy of Chloride Determination Methods and Their Predictions
At ASFiNAG, most structures are made of reinforced or prestressed concrete. In Austria strong winters are obligatory. Therefore, de-icing measures with salt are used for thawing. These substances contain chlorides, that ingress into the concrete and lead to degradation. Several elements are strongly exposed to chlorides, such as girders of overpasses and columns of bridges beside and between roadways. For condition assessment and service life prediction of existing road structures the determination of a reliable chloride content is key. The article presents the results of the chloride content of reinforced concrete obtained by two methods. One is the conventional Cl-determination described in standards. The other is the LA-ICP-MS (Laser Ablation Inductively Coupled Plasma Mass Spectrometry) method, which is a fast, reliable, accurate and high-resolution analysis method. This method allows the determination of the chloride content as a fraction of cement and additionally distinguishes between the aggregate and the cement phase. The profiles were determined densely at steps of 3 mm in depth. Regressions with different boundary conditions were used to fit the obtained data according to Fick’s second law. For comparison and prediction purposes, the corresponding convection depth as well as the chloride diffusion coefficients were determined. These parameters, as well as the fluctuations of chloride profiles for one year deliver important insights for assessment and prediction. Significant differences were observed in the results obtained by the applied analysis methods. The study addresses the origins of these differences and shows the variances when it comes to prediction of remaining service life. The results are compared and discussed to show the complex nature and sensitivity of the derived input parameters. These results show on one hand the importance for an accurate chloride analysis (LA-ICP-MS) and gives hints for an improved assessment of structures.
Study on the Accuracy of Chloride Determination Methods and Their Predictions
At ASFiNAG, most structures are made of reinforced or prestressed concrete. In Austria strong winters are obligatory. Therefore, de-icing measures with salt are used for thawing. These substances contain chlorides, that ingress into the concrete and lead to degradation. Several elements are strongly exposed to chlorides, such as girders of overpasses and columns of bridges beside and between roadways. For condition assessment and service life prediction of existing road structures the determination of a reliable chloride content is key. The article presents the results of the chloride content of reinforced concrete obtained by two methods. One is the conventional Cl-determination described in standards. The other is the LA-ICP-MS (Laser Ablation Inductively Coupled Plasma Mass Spectrometry) method, which is a fast, reliable, accurate and high-resolution analysis method. This method allows the determination of the chloride content as a fraction of cement and additionally distinguishes between the aggregate and the cement phase. The profiles were determined densely at steps of 3 mm in depth. Regressions with different boundary conditions were used to fit the obtained data according to Fick’s second law. For comparison and prediction purposes, the corresponding convection depth as well as the chloride diffusion coefficients were determined. These parameters, as well as the fluctuations of chloride profiles for one year deliver important insights for assessment and prediction. Significant differences were observed in the results obtained by the applied analysis methods. The study addresses the origins of these differences and shows the variances when it comes to prediction of remaining service life. The results are compared and discussed to show the complex nature and sensitivity of the derived input parameters. These results show on one hand the importance for an accurate chloride analysis (LA-ICP-MS) and gives hints for an improved assessment of structures.
Study on the Accuracy of Chloride Determination Methods and Their Predictions
Lecture Notes in Civil Engineering
Matos, José C. (editor) / Lourenço, Paulo B. (editor) / Oliveira, Daniel V. (editor) / Branco, Jorge (editor) / Proske, Dirk (editor) / Silva, Rui A. (editor) / Sousa, Hélder S. (editor) / Binder, Fritz (author) / Burtscher, Stefan L. (author) / Strauss, Alfred (author)
International Probabilistic Workshop ; 2021 ; Guimarães, Portugal
2021-05-08
10 pages
Article/Chapter (Book)
Electronic Resource
English
Accuracy , Chloride determination , LA-ICP-MS , Laser ablation inductively coupled plasma mass spectrometry , Chloride transport , Sensitivity analysis Engineering , Civil Engineering , Probability Theory and Stochastic Processes , Engineering Economics, Organization, Logistics, Marketing , Risk Management
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