Gammadensimetry: A method to determine drying and carbonation profiles in concrete

The aim of this paper is to describe a new and efficient method to determine drying and carbonation profiles in concrete by gammadensimetry. First, the paper focuses on density and density variation measurements. A direct calculation of porosity and moisture saturation rate is proposed. Then, the uncertainties of these measurements are assessed. The results obtained on several materials are finally analyzed and validated by comparison with classical test results. The porosity profiles agree with mercury intrusion porosimetry and carbonation results with depths obtained by pH-indicator spraying. Thus, it is shown that gammadensimetry enables to monitor the evolution of density according to depth and time. Moreover, the auscultation by gamma-ray makes it also possible to determine the water content during drying as well as the quantity of fixed carbon dioxide in concrete during the carbonation process.