Potential of Potassium Acetate Deicer to Induce ASR in Concrete, and Its Mitigation

Abstract

Increasingly airfield pavements across the United States and other parts of the world are being subjected to a new generation of alkali-acetate and alkali-formate deicers that are based on potassium acetate, potassium formate, sodium acetate, and sodium formate formulations. These deicers are considered to be more environmentally friendly than the “traditional” airfield pavement deicers such as urea and glycols and have to a large extend replaced the former ones in anti-icing and deicing applications. While the use of these new generation deicers is rapidly growing, there has been an increase in the number of reported incidences of premature deterioration of concrete airfield pavements in recent years. It has been reported that the distress in concrete pavements is particularly severe in locations that are subjected to these deicers. In most of these cases, it is suspected that the distress is primarily due to alkali-silica reaction (ASR). This paper presents the findings from a research study conducted to evaluate the potential of potassium acetate deicer to cause ASR in mortar and concrete test specimens. In addition, this paper also presents the results of tests conducted to evaluate the mitigation potential of three different fly ashes (with varying CaO content) and slag. Findings from this study indicate that potassium acetate deicer is particularly aggressive against concrete and mortars which contain aggregates that are reactive. However, concretes and mortar containing non-reactive aggregates showed no deleterious effects, upon exposure to these deicers. Among the mitigation measures evaluated, fly ashes with Ca) content less than 15% and slag appear to be effective when used at sufficient replacement levels of cement.