Effect of concrete mixtures on estimation of porosity by ultrasonic velocity

Abstract

The most used measurement is undoubtedly the measurement of porosity accessible to water. The relationship between concrete mixtures, porosity and ultrasonic velocity of concrete samples measured by ultrasonic NDT is investigated. This experimental study is interested in the relations between the ultrasonic velocity measured by transducers of 49.5mm [1,98in.] diameter and with 54 kHz frequency. Concrete specimens (160 mm [6,3in.] diameter and 320 mm [12,6in.] height) are fabricated with concrete of seven different mixtures (various W/C and G/S ratios), which gave porosities varying between 7% and 16%. Ultrasonic velocities in concrete were measured in longitudinal direction. Finally the results showed the influence of ratio W/C, where the porosity of the concretes of a ratio W/C ≥ 0,5 have correctly estimated by ultrasonic velocity. The integration of the concretes of a lower ratio, in this relation, caused a great dispersion. Porosity estimation of concretes with a ratio W/C lower than 0,5 became specific to each ratio. © RILEM 2013.