A systematic study on the reliability of stress wave/sonic-based NDE/NDT methods on grooved concrete pavements was carried out. Field measurements and numerical simulations were performed to assess the sensitivity and accuracy of sonic measurements with respect to the size (depth, width and spacing) and the orientation of grooves relative to the orientation of source-receiver array. The effects of grooving on in-situ concrete modulus and slab thickness measurements with the ultrasonic surface wave (USW) and impact echo (IE) methods were evaluated through an experimental program. A smooth 30-foot by 45-foot concrete slab was first tested. Five sections of the slab were then grooved with depths ranging from 0.25 in. to 0.5 in., widths ranging from 0.125 in. to 0.25 in. and groove spacing of 1 in. to 2 in. These sections were then tested with sensor arrays parallel and perpendicular to the orientations of the grooves. These slabs were then simulated using a finite element algorithm. The results from the experimental and numerical results were combined to recommend the optimal sensor array and interpretation algorithms. The slab thickness estimation with IE method is not sensitive (changes by less than 3%) to the orientation of the source-receiver array relative to the grooving direction. The estimated concrete modulus with the USW method depends on the orientation of the source-receiver array relative to the grooving orientation. Moduli measured with the source-receiver arrays parallel to the grooves are comparable to those measured on the same concrete without grooving irrespective of the groove depth, width and spacing. On the other hand, moduli measured with the receiver array perpendicular to the grooves decrease by up to 20% depending on the grooving depth, width and spacing.

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