Formulae for Estimating AAR Expansion in Concrete Structures Based on Ultrasonic Pulse Velocity Measurement

Ultrasonic pulse velocity (UPV) technique and core testing are common and effective means for appraisal of concrete structures. For concrete structures affected by alkali-aggregate reaction (AAR), these techniques seem not working so well. One of the major problems lies in the fact that when a concrete core is taken out of a structure, confinement to the core from surrounding concrete and reinforcement is removed. The properties of the core as determined by common tests do not reflect the actual properties of the concrete inside the structure. The assessment of mechanical properties of in-situ concrete is still a difficult task due to the lack of research on this aspect.Earlier researches by the authors and others showed that AAR expansion of the concrete inside structure is the key factor affecting mechanical properties of the concrete and hence, the accuracy of structural analysis. Accurate assessment of AAR expansion of the concrete within the structure is crucial in structural appraisal.This paper derives, based on a model of AAR affected concrete, formulae that could be used in estimating AAR expansion and concrete properties using UPV technique. An experiment verifying the formulae is also presented.