Influence of acetate and formate-based deicers on ASR in airfield concrete pavements

In the past few years, the issue of external alkalis and their influence on ASR in concrete has become more important since several concrete airfield pavements have shown ASR-distress related to the use of alkali-containing airfield deicers based on acetates and formates. Experiments with model pore solutions and cement pastes as well as speciation calculations and ASR performance tests were conducted to investigate possible mechanisms. The obtained results indicate that the solubility of portlandite is increased in the presence of acetate-based and formate-based deicers due to the formation of Ca-acetate and Ca-formate complexes. The additional release of OH- ions from portlandite and the supply of alkalis can initiate and highly accelerate ASR in concretes with reactive aggregates. There is also evidence for a reaction of ettringite with such airfield deicers. (C) 2009 Elsevier Ltd. All rights reserved.