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During concrete pavement construction, comprehensive information on concrete strength development is necessary for knowledgeable scheduling decisions. To improve in situ strength estimation, nondestructive tests can be combined to maximize available information and increase collection efficiency. Ultrasonic testing has a higher accuracy in strength estimation for early age concrete and the external device allows for more data to be easily collected, while maturity testing can use temperature models to predict strength development. A procedure was created that combines these methods and their strength models in the laboratory for improved and increased field strength data. Using the procedure allows more data to be collected with greater accuracy and provides an adjustable, predicted strength development. This improves the efficiency of fast-track construction projects without resorting to costly alternatives by providing more information on strength development of in situ concrete than traditional strength testing or nondestructive methods individually. [ABSTRACT FROM AUTHOR]

The assessment of the structural integrity of infrastructure after extreme events is an important application of nondestructive technology. Advancements in elastic wave-based methods in recent years have allowed for productive and accurate quantitative analysis which was previously lacking. In this study, ultrasonic array measurements coupled with a modified signature analysis method were implemented for damage detection purposes. Full-scale testing of a reinforced concrete column subjected to simulated earthquake loading was tested using ultrasound nondestructive testing at various stages of loading. A signature analysis technique was adapted to create improved reconstructions and was coupled with a quantitative analysis incorporating Pearson’s correlation coefficient. The results demonstrated the ability to detect internal damages and defects prior to appearance on the surface using one-sided access, showing promise for health monitoring applications. [ABSTRACT FROM AUTHOR]

Quantitative nondestructive characterization of defects and inclusions in portland cement concrete structures are realized in this paper via extended reconstructions for linear array ultrasound systems. This is accomplished through generalization of traditional Kirchhoff-based synthetic aperture focusing technique migration to mitigate the effects of limited aperture and handle multiple scans as a single virtual array with increased effective aperture. Pearson’s correlation is utilized to account for uncertainty in relative position of individual measurement and mitigate the need for robotic precision when placing adjacent scans. The robustness of the method is demonstrated on artificially generated data as well as in-situ measurements for assessment of internal portland cement concrete characteristics such as inclusions and cracks. [ABSTRACT FROM AUTHOR]

Ultrasonic tomography is an emerging method of nondestructive concrete pavement diagnostics which can be used for improved quality assurance/quality control during concrete pavement construction and assist in rehabilitation decision making. Detection of flaws using ultrasonic tomography requires significant effort and user expertise. To address these limitations, a quantitative method for determining the presence of defects in concrete pavements was developed. The proposed method is an adaptation of the recently developed impact-echo signature analysis method (IESA), which is used for comparison of impact-echo signals. The proposed two-dimensional ultrasonic tomography signature analysis (2D-UTSA) method was used to compare two-dimensional B-scans obtained using a commercial test system in field trials at the Minnesota Rd. Research Facility and the Federal Aviation Administration's National Airport Pavement Test Facility. Analysis of the results showed that the 2D-UTSA method is capable of identifying subsurface defects. [ABSTRACT FROM AUTHOR]

Ultrasonic tomography is a non-destructive testing method that allows for the internal visualization of concrete structures without causing any damage. This technique is widely employed to detect reinforcement and various types of damage, including voids, cracks, rebar corrosion, and debonding, among others. To enhance the accuracy and clarity of concrete tomograms, numerous image generation techniques have been explored. With the ever-increasing volume of information, it can become challenging to grasp the overall landscape and identify areas for improvement. The present work offers a comprehensive systematic review of the diverse image reconstruction techniques employed and the innovative developments within this research field. The prevalent techniques for both transmission and reflection tomography have been analyzed, delineating their respective characteristics. Furthermore, enhancement techniques have been recorded, and their discussion is provided. This comprehensive overview provides the basis for outlining future developments in ultrasonic tomography for concrete elements. [Display omitted] • Review of image reconstruction (IR) methods for ultrasonic tomography of concrete. • Contextualization of concrete tomography scenario among other research fields. • Discussion of IR techniques for concrete transmission and reflection tomography. • New enhancement methods for improving image accuracy are presented and discussed. • Overview of future possibilities in concrete imaging with ultrasonic tomography. [ABSTRACT FROM AUTHOR]

• We modified the imaging condition of reverse time migration to reduce the artifacts. • We introduced a new normalization factor to consider more precisely the spreading attenuation in imaging condition. • We introduced a modification factor to the imaging condition to consider scattering attenuation in concrete members. • We showed that using the proposed approaches one can image the entire boundary of a cavity located in a concrete medium. Cross-correlation imaging condition of reverse time migration generates high-amplitude artifacts in the reconstructed images. In addition, due to geometrical spreading and scattering attenuations, this imaging condition assigns amplitudes to the points of the reconstructed image that are not a true representative of the reflection coefficient of the scanned medium at those points. These all can lead to a reduction in quality and misinterpretation of the reconstructed images. In this paper, we proposed new imaging conditions to mitigate high-amplitude artifacts and to assign more accurate amplitudes to an RTM image by considering geometrical spreading and scattering attenuation in concrete members when horizontal shear waves are used for imaging. We used data obtained by transmitting horizontal shear waves to 3D synthetic homogeneous and concrete specimens and demonstrated the effectiveness of the new imaging conditions. [ABSTRACT FROM AUTHOR]

Improving early-age concrete strength measurement is an important step toward opening new pavements to traffic quickly without risking long-term performance due to early age damage. The maturity method is well established as an appropriate estimation of strength; however, it contains certain unavoidable limitations. Non-destructive ultrasonic testing using shear wave velocity can be used as a complementary testing. An in-situ comparison of these strength estimation methods was performed on a 200-mm thick concrete pavement for two weeks after placement. Both methods predicted reasonable concrete strength gain trends for in-situ pavement. The linear array ultrasonic method was found to have major advantages regarding portability, strength-gain variation and testing speed. [ABSTRACT FROM AUTHOR]