In the research project "Durability of concretes with clinker-efficient CEM II/C and CEM VI cements" (Link), measures to optimise the durability of concretes with clinker-efficient cements are being investigated. The focus of the aforementioned project is on investigations into carbonation and chloride penetration. In addition to this, the research project „Freeze-thaw resistance of concretes with clinker-efficient CEM II/C and CEM VI cements“ will carry out tests on freeze-thaw resistance.
Both in various VDZ research projects and in tests for general technical approvals, it has been shown that concretes with CEM II/C-M, CEM VI or similar cements do not always reliably pass the relevant freeze-thaw resistance tests. For a broad application of these cements the extent to which the concrete technology parameters (in particular the water-cement ratio) can and must be adapted to achieve the required durability of concretes with new, clinker-efficient cements is to be investigated. It has been shown that a reduction in the w/c ratio also leads to a significant improvement in freeze-thaw resistance in the cube method for concretes with clinker-efficient cements.
In addition, the cube test method consists of a pre-storage period of 28 days and a test duration of 100 days with one freeze-thaw cycle per day. A shortened test duration of 50 days with two freeze-thaw cycles per day, as defined for example in the CF/CDF method, would enable a more flexible and efficient use of the test method and significantly accelerate the approval test procedures. This aspect was also analysed in the research project. It can be concluded from the results that accelerated testing of frost resistance using the cube method with two freeze-thaw cycles per day (test duration of 50 d) does not lead to significantly different results in terms of scaling.
