The influence of calcium chloride deicing salt on phase changes and damage development in cementitious materials. (November 2015)

• Record Type: Journal Article
• Authors: Farnam, Yaghoob; Dick, Sarah; Wiese, Andrew; Davis, Jeffrey; Bentz, Dale; Weiss, Jason
• Is Part Of: Cement & concrete composites. Volume 64(2015)
• Page Start: 1
• Page End: 15
• Publication Date: 2015-11
• Subjects: Calcium oxychloride -- Concrete -- Deicing salt -- Freeze-thaw -- Damage -- Phase change; Composite-reinforced concrete -- Periodicals; Concrete -- Periodicals; Composite materials -- Periodicals; Composites de ciment -- Périodiques; Béton -- Périodiques; Composites -- Périodiques; Béton léger -- Périodiques; Cement composites; Composite materials; Composite-reinforced concrete; Concrete; Lightweight concrete; Periodicals; Electronic journals; 620.135
• DOI: 10.1016/j.cemconcomp.2015.09.006
• Languages: English
• ISSNs: 0958-9465

Abstract

Abstract: The conventional CaCl2 –H2 O phase diagram is often used to describe how calcium chloride behaves when it is used on a concrete pavement undergoing freeze-thaw damage. However, the chemistry of the concrete can alter the appropriateness of using the CaCl2 –H2 O phase diagram. This study shows that the Ca(OH)2 present in a hydrated portland cement can interact with CaCl2 solution creating a behavior that is similar to that observed in isoplethal sections of a ternary phase diagram for a Ca(OH)2 –CaCl2 –H2 O system. As such, it is suggested that such isoplethal sections provide a reasonable model that can be used to describe the behavior of concrete exposed to CaCl2 solution as the temperature changes. Specifically, the Ca(OH)2 can react with CaCl2 and H2 O resulting in the formation of calcium oxychloride. The formation of the calcium oxychloride is expansive and can produce damage in concrete at temperatures above freezing. Its formation can also cause a significant decrease in fluid ingress into concrete. For solutions with CaCl2 concentrations greater than about 11.3% (by mass), it is found that calcium oxychloride forms rapidly and is stable at room temperature (23 °C).