Understanding the air void content in concrete is crucial since it significantly influences the durability and strength of the material, especially in environments susceptible to freeze-thaw cycles. This report introduces an advanced nondestructive testing (NDT) method for the in-situ detection of air voids in concrete by employing diffusive ultrasound. Focusing on the ultrasound attenuation coefficient, this research established a strong correlation with key air void metrics, including the volumetric ratio and spacing factor, as outlined in ASTM C457. The study also undertook a comparative analysis of ASTM C457 methods B and C, revealing the instrument-dependent variability in measuring air voids. One pivotal discovery was that ultrasound attenuation in concrete is majorly influenced by air voids and aggregates, with a relatively minor contribution from cement. This methodology not only offers a novel approach for accurately assessing air void content but also enables visualization of air void distribution in concrete infrastructures like pavements. The findings of this research offer insights for enhancing concrete quality control and ensuring structural integrity in construction, particularly when the in-place air voids conditions are of interest.

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concrete, air voids, NDT, ultrasound, diffusive, scattering

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Performing Organization

Joint Transportation Research Program

Publisher Place

West Lafayette, Indiana

Date of this Version