Title: Cement-alkali level as it affects air-void statility [sic], freeze-thaw resistance, and deicer scaling resistance of concrete
Description: Parameters of air-void systems in freshly-mixed and hardened air-entrained concretes, with cement-alkali levels of 0.21%, 0.60%, and 1.20% as Na2O by mass of cement, were compared. Additionally, four different generic types of air-entraining admixtures were utilized to investigate the effects these admixtures have on the air-void system at various cement-alkali levels. These air-entraining admixtures were salts of fatty acids, sulfonated hydrocarbons, alkylbenzylsulfonates, and neutralized Vinsol resin (NVR). Concretes with cement-alkali contents greater than or equal to 0.60% and containing air-entraining admixture neutralized Vinsol resin or based on salts of fatty acids produced reasonably stable air-void systems, whereas sulfonated hydrocarbon-based and alkylbenzylsulfonate-based air-entraining admixtures produced relatively unstable air-void systems as the cement-alkali level increased. Deicer scaling and freeze-thaw tests were conducted. Concretes prepared with an air-entraining admixture based on salts of wood resins (NVR) showed a tendency for less severe scaling at the highest cement-alkali content. With regard to freezing and thawing, our tests indicated that the impact on the air-void systems of increased alkali in cement and periodic agitation had little, if any, effect on the durability factor of these concretes. However, mass change and visual examination revealed some surface deterioration, especially for those subjected to salt solution.
Subjects: Alkali-aggregate reactions, Concrete, Deterioration