Fractional‐order freezing‐and‐thawing damage model for hydraulic concrete subjected to variable temperature processes

Abstract

AbstractSince research on the freezing‐and‐thawing damage experienced by hydraulic concrete subjected to variable temperatures is currently rudimentary, it is difficult to use existing models to quantitatively reflect the damage of actual hydraulic engineering concrete under such conditions. This study first presents a formula to calculate the equivalent damage age through an analogy with the equivalent age theory, and the results of this formula can comprehensively reflect the relationship between the freezing‐and‐thawing process at variable temperatures and concrete damage. Then, this study establishes a fractional freezing‐and‐thawing damage model for hydraulic concrete subjected to freezing‐and‐thawing cycles at variable temperatures according to fractional calculus theory. New model parameters for freezing‐and‐thawing damage are identified and optimized with existing testing data acquired under variable freezing‐and‐thawing temperatures. Moreover, the applicability of the new model is verified with different freezing‐and‐thawing temperature data obtained from supplemental freezing‐and‐thawing tests performed in this study. The analysis results show that the new concrete freezing‐and‐thawing damage model can accurately reflect the changes in concrete strength during freezing‐and‐thawing cycles at variable temperatures.