Effect and Mechanism of SAP on Freezing Resistance of Concrete

Superabsorbent polymers (SAP) exhibit excellent water retention and storage properties, and is one of the preferred materials for internal curing and enhancing the freeze-thaw resistance of concrete.This paper explores the mechanism by which SAP enhances this property and reviews the effects of various parameters on concrete freeze-thaw resistance. The results indicate that the water release behavior of SAP primarily consists of an osmotic pressure-controlled stage and a humidity-controlled stage. Post water release, SAP forms macro pores and gel pores within the concrete, thereby enhancing its freeze-thaw resistance. Factors such as the dosage, particle size, and mixing method of SAP all influence the freeze-thaw resistance of concrete. The optimal dosage and particle size should be determined based on the water absorbency of SAP and the air-void spacing factor, respectively, with dry mixing being more beneficial for enhancing the freeze-thaw resistance of concrete. In view of the existing problems, it is suggested that the influence of SAP on the freezing resistance of concrete under different water-binder ratio can be studied in the future, establish a correlation model between SAP pore size and frost resistance of concrete under different water-to-binder ratios.