Modification of the RCM test to optimize measurement precision, test duration and cost-effectiveness - Development of practice-oriented laboratory and construction site tests to prove the conformity and identity of concrete for chloride-exposed components

Modification of the RCM test to optimize measurement precision, test duration and cost-effectiveness – Development of practice-oriented laboratory and construction site tests to prove the conformity and identity of concrete for chloride-exposed components. As part of the publication of the new “BAW-Merkblatt MDCC” [1], a semiprobabilistic concept to ensure durability was introduced for the first time. It can be assumed that this development will also continue in national and international regulations. What is missing, however, are practical and at the same time economic tests of the material resistance, which can be carried out within the framework of initial type testing, conformity testing and identity testing. In this context, the present article summarizes the currently available tests for determining the material resistance to chloride penetration (rapid penetration test RCP-Test, rapid migration test RCM-Test, test of electrolytic resistance) and critically examines them with regard to test accuracy, time expenditure and suitability for practical use. On the basis of these findings, a new testing method is developed on the basis of the existing RCM test set-up, which can be used within the scope of initial type testing and is referred to as the Modified Chloride Migration Test MCM-Test. In this test, the charge flow is determined at a variable initial voltage during a specified test duration; the resulting material value is referred to as the SCFR (Specific Charge Flow Rate) value. In 32 test series with 17 different concretes it was shown that the correlation between SCFR value and chloride migration coefficient DRCM was very good. For conformity and identity testing, a test based on electrolytic resistance measurement is proposed, which also shows a good correlation with the DRCM value regardless of the binder combination. © 2019, Ernst und Sohn. All rights reserved.