• The International Concrete Abstracts Portal is an ACI led collaboration with leading technical organizations from within the international concrete industry and offers the most comprehensive collection of published concrete abstracts.

International Concrete Abstracts Portal


Title: Nondestructive Testing of Bridge Decks: Case Study and Suggestions

Author(s): Yail J. Kim and Jun Wang

Publication: Structural Journal

Volume: 120

Issue: 2

Appears on pages(s): 3-17

Keywords: bridge decks; delamination; evaluation; ground-penetrating radar (GPR); nondestructive testing

DOI: 10.14359/51734822

Date: 3/1/2023

This paper presents a case study on the evaluation of bridge decks using various nondestructive test methods. In consultation with a local transportation agency, five representative bridges are selected and assessed by qualitative/empirical (visual inspection and chain drag) and quantitative (ground-penetrating radar [GPR] and rebound hammer) approaches. The primary interest lies in quantifying delaminated areas in deck concrete, which has been a major problem in the bridge engineering community because conventional GPR contours provide a wide range of deterioration that differs from the amount of actual repair. A consistent condition rating of 7 has been assigned to all decks over a decade old, aligning with the outcomes of chain drag: delamination of less than 3.31% of the entire deck area. The variable scanning rates of GPR (4 to 20 scans/ft [13 to 66 scans/m]) influence contour mapping, whereas mutual correlations associated with these rates are insignificant. A tolerable range of ±20% is suggested for interpreting GPR contour maps at a 95% confidence interval. The performance threshold limit of 20% used to identify degraded concrete in rebound hammering exhibits a coefficient of correlation of 0.967 against GPR-based deterioration; however, the results of these methods deviate from the areas of actual repair. For practical implementation, analytical and computational models are formulated to decompose the intensity of GPR scales into two categories: initiation and progression of corrosion (0 to 39%) and delamination of deck concrete (40 to 100%), which show good agreement with the repaired areas. Parametric investigations emphasize the significance of reinforcing bar spacing and concrete cover in determining the extent of delamination in the concrete decks.