Superabsorbent Polymers for Internal Curing Concrete: An Additional Review on Characteristics, Effects, and...

Superabsorbent polymers (SAPs) are a promising admixture that can provide internal curing to freshly cast concrete and enhance concrete properties. Although many reviews have explored aspects of SAPs, the links among SAPs' chemical and physical properties, internal curing behaviors, concrete performance, and their large-scale applications are often weakly elucidated. This paper provides an additional review of the chemical structures and physical dimensions of SAPs and their effects on the internal curing kinetic behavior as well as on concrete properties, such as workability, strength, and durability. In addition, different approaches to introducing SAP particles into concrete mixtures are also summarized. Case studies on the use of SAPs in the concrete industry are introduced to provide a better understanding of the greatest potential of SAPs in field applications. The results confirm that the utilization of SAPs in concrete mixtures provides multiple benefits such as improved water curing, reduced shrinkage, and enhanced workability. Selecting the appropriate SAPs is crucial and involves considering factors like absorption rate, durability, and stability. However, achieving uniform distribution of dry SAPs in concrete poses challenges. Further research is required to gain a deeper understanding of the impact of SAPs on transport properties and frost durability. Additionally, the absence of a standard makes it difficult to maintain consistent water-to-cement ratios. These findings provide a theoretical foundation for using SAPs to enhance concrete performance while also highlighting future research directions and challenges. In this article, scientists, engineers, and contractors will find a comprehensive explanation encompassing laboratory investigations, field implementation, and relevant guidance.