Investigating the dual influence of freezing-thawing cycles and chloride ion penetration on GGBS-AEA concrete deterioration

The synergistic effects of freezing-thawing (FRTH) cycles and chloride ion (Cl-) penetration in concrete caused amplified damage and complex degradation mechanisms. This study scrutinizes the evolution of FRTH damage in concrete amalgamated with ground granulated blast-furnace slag (GGBS) and air-entraining admixtures (AEA), either individually or in conjunction. Along with examining steel corrosion parameters, we investigated the distribution of free Cl- (Cl)freein concrete subjected to diverse FRTH cycles. Our findings suggest that the degree of FRTH damage can be accurately assessed through the analysis of changes in the concrete formation factor. Intriguingly, the incorporation of AEA markedly bolsters the concrete's resistance to FRTH degradation in contrast to GGBS. An exponential correlation has been identified between the degree of FRTH damage and the Clfree diffusion rate, as well as an exponential relationship between the FRTH damage degree and the time-dependent reduction coefficient. Additionally, FRTH damage instigates a decline in the Cl- binding capacity of concrete. Concrete that contains both GGBS and AEA demonstrates commendable resistance to Cl- penetration and steel corrosion subsequent to FRTH damage. This research furnishes novel insights into the evaluation and augmentation of concrete's serviceability under the simultaneous influences of FRTH cycles and Cl-.