EVALUATION OF DENSITY AND VOLUME CHANGE DISTRIBUTION INSIDE MORTAR UNDER DRYING SITUATION USING X-RAY CT

Abstract

The volume change of concrete materials during drying is influenced not only by the characteris-tics and volume fraction of the paste but also by the quality of the aggregate. Various recycled mate-rials have been repurposed as concrete aggregates for waste valorization. However, conventional quality testing methods for aggregates may be insufficient for recycled materials. The effect of re-cycled materials can then be evaluated through how they behave inside the concrete. In this study, how drying affects the interior of cylindrical mortar specimens has been probed via X-ray CT image intensities and using the strains calculated by the digital volume correlation method. As a result, the relationships between the intensity reduction rate and the mass reduction rate were clarified. The re-lationship between the volumetric strain and the intensity reduction rate in the horizontal section was similar to the one between the mass reduction rate and the length change rate. It was shown that the vertical strain inside the specimen remains unchanged in the radial direction, while the area strain increases towards the surface of the sample.