Effects of water absorption on performance of concretes subjected to accelerated freezing-and-thawing tests

A research project was carried out with the aim of evaluating how to better interpret the results of ASTA C 666 Procedure A tests in assessing the long-term in-place resistance to freezing and thawing of high-performance concrete (HPC). The results indicate that absorption of external water is a key parameter controlling the mechanisms of internal damage due to freezing-and-thawing cycles. No significant deterioration was observed when absorption of external water was prevented during the cycles. This suggests that the freezing-and-thawing resistance of concrete is not governed solely by the initial saturation state of the paste; the water transport between the external environment and the cement paste also plays a role. For HPC, the characteristics of the air-void system that are necessary to obtain an adequate protection from ASTM C 666 Procedure A accelerated freezing. and thawing tests represent a conservative estimation of the minimum values required.