Monitoring of alkali-silica-reaction (ASR) in cementitious concretes by microwave non-resonant waveguide measurements.

The length expansion measurements implemented in the literature as the reference methodology (the ASTM C1293 standard) for alkali-silica-reaction (ASR) formation analysis requires measurements at laboratory and thus is not appropriate for the field site, rendering new non-destructive evaluation tools for detection and quantification of the ASR formation. In the present study, we apply microwave reflection and transmission measurements for the first time in the literature for detection of ASR formation in ordinary Portland cement (OPC) concretes. It is observed that microwave transmission measurements are more sensitive than reflection measurements to ASR formation in OPC concretes. A correlation curve is established for the first time as an evaluation and prediction tool for the ASR formation in OPC concretes. The outcome of the presented study shows a high potential of microwave signals as a field evaluation tool for ASR formation at the field site.