Germany – Research and development services and related consultancy services – FE 08.0283/2026/BCG - Einfluss verschiedener AKR-Prüfzementchargen auf die statistische Verteilung von Dehnungen im Schnellprüfverfahren mit verschiedenen Gesteinskörnun-gen

FE 08.0283/2026/BGB - Influence of different AKR test cement batches on the statistical distribution of strains in the rapid test method with various aggregates

To prevent an alkali-silica reaction (AKR) that is harmful to concrete on concrete road surfaces, a road construction-specific expert regulation according to General Circular on Road Construction (ARS) No. 04/2013 is currently being applied. The preliminary investigations are the rapid test method according to TP-Beton-StB 1.1.11 or the mortar rapid test according to TP-Beton-StB 1.1.12. These methods enable monitoring of the aggregates with regard to a possibly changing alkali reactivity with progressing decomposition in the natural stone quarry or gravel pit. For both test methods, a uniform AKR test cement CEM I 32,5 R, which is managed by the Verein Deutscher Zementwerke (VDZ), has been prescribed so far. Since this cement will no longer be available in Germany from the end of 2024, all testing institutes will have to switch to an available CEM I 42,5 R in the future. Initial comparison tests at the VDZ and at the TU Hamburg/Harburg have shown, however, that different results are obtained with the CEM I 42,5 R in the rapid test method than with the previous delivery batches of the CEM I 32,5 R – the comparability of the test results is therefore not directly given. The research project aims to investigate the influence of different AKR test cement batches on the statistical distribution of strains in the rapid test method with various aggregates (AKR reference aggregate of the VDZ and chippings). The investigation of the influence of different AKR test cement batches enables the identification of specific cement properties that significantly determine the strain development in the rapid test method and in the mortar rapid test. Based on this, binding requirement criteria for future test cement batches can be defined to minimise future fluctuations between different batches.