A Comparative Study of Test Methods for the Resistance of Concrete to Freeze-Thaw Cycles

Resistance to freeze-thaw cycles is an important factor for the durability of concrete roads and structures in an outdoor environment. In many European countries, current national standards for concrete exposed to frost are limited to the composition of the mixture: minimum cement content, maximum water-cement ratio, and in some cases a required entrained air content. This approach is unanimously considered as inadequate. A prediction of the scalling resistance under freezing and thawing conditions is necessary. The draft European standard prENV 12390-9 aims at the mandatory use, in time, of one of the following three methods: the slab test , the cube test or the CF-CDF test. In Belgium, two test methods have been used so far: NTN-018 of Probeton and ISO/DIS 4846-2. The latter is the reference method prescribed in standard tender specifications RW99 (Walloon Region) and SB250 (Flemish Region). The introduction of the future European standard necessitates a comparative study of the test methods described in it, not only between them, but also with the methods used in Belgium. This is necessary to set new method-specific acceptance criteria for concrete, as well as criteria to make a choice of the most suitable method in relation to the type of concrete considered. This project evaluates the different test methods described in the European standard and compares the results obtained on differents types of concrete by the different methods. This paper will present the test methods and the results, obtained on concrete mixtures used on different types of roads and constructions.