The research presented in these nine papers of this special issue offer a fresh look at the topic of freezing and thawing from five perspectives. This important and classic research topic of freeze-thaw in concrete is the subject of rapidly advancing designs. Some of the topics covered in this special issue include:

– assessment of measurement techniques to quantify air void systems for fresh concrete using the super air meter and hardened concrete by comparing two dimensional scans with three dimensional results from tomography

– effectiveness of different surfactants on the air void system

– assessment of testing procedures that evaluate current tests methods for concrete scaling

– suggestions for how test procedures can be developed to improve the testing and better relate the results to field observations

– methods to measure a concretes resistance to pop-outs

– development of new criteria that can be used for identifying freeze-thaw resistant concrete

– development of a new testing procedure to assess a pastes susceptibility to a reaction between certain deicing chemicals and the cementitious matrix

– the use of an emerging new material, super absorbent polymers, and reports on the benefits that these materials may have in improving the freeze-thaw resistance of concrete