Prediction of frost resistance of concrete at different freezing temperatures

The article proposes a method for evaluating the frost resistance of concrete at actual operating temperatures, using measurement results at temperatures that are regulated by current standards. Frost resistance was evaluated by determining the amount of water freezing at different temperatures, based on the measured adsorption isobars and the obtained relationship between the freezing temperature of water in concrete pores and relative humidity. A comparison of the calculated values of the frost resistance of concrete with those got based on direct measurements showed the adequacy of the calculation model. The proposed experimental-analytical method for evaluating the frost resistance of concrete at different freezing temperatures allows in a small amount of time to get more complete information about the behavior of the material in frosty weather under real operating conditions than is provided for by existing methods. An analysis of the dependence of frost resistance on temperature also makes it possible to identify the temperature regions where it changes most strongly, and to shift, if necessary, these regions to lower or higher temperatures due to the change of the composition and technology of concrete production.