Study on 3D spatial distribution of steel fibers in fiber reinforced cementitious composites through micro-CT technique

Fiber distribution in fiber reinforced cementitious composites (FRCC) is a critical factor affecting the reinforcement of fiber to composites. However, evaluation of fiber distribution in 3-dimension (3D) space has always been a great challenge due to the lack of transparency of FRCC and random distribution of fiber. To address this problem, micro-computed tomography (micro-CT) was used to characterize fiber distribution in this study, which permitted 3D visualization within the materials. By 3D image reconstruction, processing and analysis of CT images, the curves of fiber orientation distribution (FOD) and fiber spacing distribution (FSD) in cementitious composites can be obtained, and the orientation factor and dispersion coefficient of fiber can also be determined. The effect of aggregate size and content on fiber orientation distribution in cementitious composites is more obvious than that on fiber spacing distribution. Compared to conventional approach of 2D image analysis of cross-section of FRCC, the micro-CT image technique appears more intuitive and accurate, especially in the assessment of fiber dispersion.