Application of X-ray computed tomography to characterise the early hydration of calcium aluminate cement

Abstract

Techniques that monitor in situ the setting and hardening of calcium aluminate cements (CACs) are of interest to the engineering community. This paper focuses on one non-destructive technique, X-ray computed tomography (CT). The early hydration of the cement can be followed from a few minutes to a few hours after mixing. This technique is based on both X-ray absorption measurements and qualitative observations in chosen axial cross-sections. Results concerning an aluminous cement, Secar 71, are presented (water-to-cement weight ratio: 0.33; duration: 0–24 h). Information deduced from these measurements clearly show that a strong variation of X-ray absorption values occurs during the early age of hydration. Both quantitative and qualitative analyses of CT data allow a chronology of cement setting to be proposed.