The CDF test (Capillary Suction, De-icing agent and Freeze-thaw-test) tests the resistance of concrete to freeze-thaw attack and de-icing agents (mostly sodium chloride). In order to carry out the test, concrete cubes with an edge length of 15 centimetres are manufactured in our concrete laboratory. The concrete cubes initially harden in a teflon mould and are then cured in a water bath. The specimens are then dry stored for 21 days, before being immersed in a sodium chloride solution (3%) for seven days. Having been cleaned in an ultrasonic bath to remove any loose elements, the resistance of the concrete to freeze-thaw cycles and de-icing salt is tested.
To do this, the specimens are once again placed in a sodium chloride solution (3%) and subjected to the following temperature cycle in special frost containers over a period of 12 hours:
- Temperature change from +20°C to -20°C over four hours
- Maintaining -20°C for three hours
- Temperature change from -20°C to +20°C over four hours
- Maintaining +20°C for one hour
The complete CDF test comprises a total of 28 freeze-thaw cycles, i. e. the test will be completed after 14 days. Altogether, there are 49 days required for the implementation of the testing and manufacture of the specimens.
For the assessment of the CDF test, the dry mass of the scaled material from the surface of the test specimens is determined. There is no limit value or acceptance criterion for the CDF test involving the maximum permitted scaling of concrete after 28 freeze-thaw cycles in any German or European standard. Regarding [1 or 2], an assessment of concrete for hydraulic engineering structures or for exposure class XF4 with the CDF test and 3% sodium chloride solution using the acceptance criterion for the scaling of 1500 kg/m² after 28 freeze-thaw cycles is possible on specimens that have been manufactured in the laboratory and whose test surfaces have been formed against Teflon.
Special feature of CIF Test
The CIF Test (Capillary suction, Internal damage and Freeze-thaw test) involves a testing procedure to assess the internal damage caused to concrete. For this purpose, demineralised water is used as the freezing medium instead of 3% sodium chloride. With the CIF Test, the changes to the ultrasonic transmission time measurement or resonance frequency are determined during the 28 freeze-thaw cycles, which may be used as a measure for the internal damage to the microstructure caused by micro cracks. The internal damage is caused by the so-called micro-ice-lens pump.
 Bundesanstalt für Wasserbau, BAW (Hrsg.): Merkblatt : Frostprüfung von Beton. Karlsruhe, 2004-12 (BAW-Merkblatt)
 Müller, Harald S.; Guse, Ulf: Zusammenfassender Bericht zum Verbundforschungsvorhaben "Übertragbarkeit von Frost-Laborprüfungen auf Praxisverhältnisse". Berlin : Beuth, 2010 (DAfStb: Schriftenreihe 577)