| Popis: |
Predominant SAPs used for internal curing are anionic gels, such as polyacrylamide, polyacrylic acid, and polyacrylate. They contain or can be hydrolyzed to form carboxylate functional groups. This allows them to retain water up to a few hundred times their dry weight, especially in a high pH environment. SAPs’ swelling behavior is desirable, but other characteristics of SAPs are important for their application as internal curing agents. These anionic SAPs are not only sensitive to the pH environment but also the types of ions. SAPs show less swelling in a calcium-rich solution than in a sodium-rich solution at the same pH. This has direct implications for internal curing because the cement pore solution is rich in various kinds of cations. |
