Reporting ASR in US Airfield Runways

In the present study, alkali silica reactivity (ASR) in airfield runways (pavements) is reported based on investigation of two US airports. The study includes in-field detection of ASR distress features followed by detailed laboratory investigation of cores collected from strategic locations. This two-tire approach was found to be most effective for definite identification of ASR and assessment of distress level of concrete. Application of uranyl acetate fluorescence method (UAFM) to identify ASR gel was appraised both in field and laboratory. Climatic parameters (relative humidity, rainfall, temperature), information related to use of supplementary cementitious materials in concrete and application of de-icing salt, age of pavement, etc. were considered for assessing the damage due to ASR. The present investigation reveals that ASR was the main cause of distress in older pavements of the first airport, whereas freeze-thaw was identified as an additional distress mechanism for the second.