Water in jet fuels is an important concern for the aeronautical industry, especially at freezing temperatures, for which ice-clogging phenomena may occur in the fuel-feeding system, with a risk causing accidents. In this work, ice particles formed from water addition in jet A-1 fuel have been characterized by X-ray Micro-Computed Tomography (mu CT) at -18 +/- 2 degrees C. For this purpose, an experimental sampling campaign was con-ducted in a fuel-icing test bench designed to characterize the properties of aeronautical filters. The samples were conditioned, transported, stored under cold-stable conditions and afterward preserved using a specific cryogenic cell during the X-ray scans. After image processing and analysis, the three dimensional (3D) images allowed us to access the shape complexity of the particles at a resolution of 5 mu m. The different samples gave re-peatable and coherent results, exhibiting wide size distributions of the ice particles, ranging from 20 to 970 mu m with a peak between 100 and 400 mu m. The increase of the water content volumetric fraction (C) as well as that of the time by which the ice particles were recirculating in the injection loop (tau), showed tendencies towards wider and smaller size distributions, respectively. The sphericity indexes (psi) were higher than 0.7 for similar to 70% of particles, indicating a significant trend to rounded shapes. The mean curvature distributions of the agglomerates showed some displacements towards concave surfaces at high C, and towards convex surfaces at longer tau. This illustrates the occurrence of more complex structures for higher water contents and the & ldquo;grinding effect & rdquo; of the recirculating time. (C) 2021 Elsevier B.V. All rights reserved.