title: The Influence of Calcium Chloride Deicing Salt on Phase Changes and Damage Development in Cementitious Materials.
abstract: The conventional CaCl2-H2O 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-H2O phase diagram. This study shows that the Ca(OH)2present in a hydrated portland cement can interact with CaCl2solution creating a behavior that is similar to that observed in isoplethal sections of a ternary phase diagram for a Ca(OH)2-CaCl2-H2O 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 CaCl2solution as the temperature changes. Specifically, the Ca(OH)2can react with CaCl2and H2O 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 CaCl2concentrations greater than about 11.3 % (by mass), it is found that calcium oxychloride forms rapidly and is stable at room temperature (23 °C).
authors.affiliation: Graduate Research Assistant, Lyles School of Civil Engineering, Purdue University, 550 Stadium Mall Dr., West Lafayette, IN 47907, USA.
authors.forename: Yaghoob
authors.initials: Y
authors.lastname: Farnam
authors.affiliation: Undergraduate Research Assistant, Lyles School of Civil Engineering, Purdue University, 550 Stadium Mall Drive, West Lafayette, IN 47907, USA.
authors.forename: Sarah
authors.initials: S
authors.lastname: Dick
authors.affiliation: Graduate Research Assistant, Lyles School of Civil Engineering, Purdue University, 550 Stadium Mall Dr., West Lafayette, IN 47907, USA.
authors.forename: Andrew
authors.initials: A
authors.lastname: Wiese
authors.affiliation: Materials Research Engineer, Materials Measurement Science Division, National Institute of Standards and Technology, 100 Bureau Drive, Stop 8615, Gaithersburg, MD 20899, USA.
authors.forename: Jeffrey
authors.initials: J
authors.lastname: Davis
authors.affiliation: Chemical Engineer, Materials and Structural Systems Division, National Institute of Standards and Technology, 100 Bureau Drive, Stop 8615, Gaithersburg, MD 20899, USA.
authors.forename: Dale
authors.initials: D
authors.lastname: Bentz
authors.affiliation: Jack and Kay Hockema Professor of Civil Engineering, Director of Pankow Materials Laboratory, Lyles School of Civil Engineering, Purdue University, 550 Stadium Mall Dr., West Lafayette, IN 47907.
authors.forename: Jason
authors.initials: J
authors.lastname: Weiss
keywords: Calcium Oxychloride; Concrete; Damage; Deicing Salt; Freeze-Thaw; Phase Change