ABSTRACT
Crack location in concrete pavement has always been a major focus for maintenance and rehabilitation. However, most cracking evaluation methods emphasize in well-developed surface cracking, not giving information about bottom-up or half-height cracks still in development. This paper addresses visible and non-visible (incipient) crack identification in an experimental section of a short Continuously Reinforced Concrete Pavement (CRCP) constructed in Brazil. As the pavement presented an unusual cracking pattern (less visible cracks at the slab surface than traditional CRCP), there was a need to verify if most cracks were not yet fully developed. The ultrasonic testing procedure is described as well as a novel signal interpretation method, employed to identify freeze and thaw and alkali-silica reaction distresses in concrete slabs in previous studies. This technique provides a concrete quality indicator for each ultrasonic measurement. Results show a 100% correlation of the indicator in a continuous scan survey with the visible cracks’ location and indicate the potential location of 19 cracks not yet apparent at the slab surface. Four potential incipient cracks, firstly discovered with the indicator, were visually confirmed as surface-visible cracks in later crack surveys.
