Characterization of fiber distribution in steel fiber reinforced cementitious composites with low water-binder ratio

Image analysis technique is introduced to characterize fiber distribution in steel fiber reinforced cementitious composites. Through cutting and polishing of specimen, image acquisition of specimen surface, extraction of fiber feature, and measurement of related fiber parameters, i.e., dispersion coefficient and orientation factor, are given to quantitatively analyze fiber distribution. Effects of specimen size, fiber volume fraction and aggregate characteristics on fiber distribution are discussed. Results show that the dispersion coefficient increases with the increase of specimen size and with the decrease of fiber volume fraction and aggregate size, but the changes are small. The orientation factor of fiber is affected by boundary effect, while the influence will get smaller and smaller with the increase of specimen size, especially for the specimen size larger than 50 mm. With the increase of fiber volume fraction, the orientation factor in each direction deviates from 0.5, and the orientation factor in y-direction decreases. Aggregate characteristics have a significant effect on fiber distribution, with the increase of aggregate size, the orientation factors in xand ydirections increases, while that in z-direction decreases. With the increase of aggregate content, the orientation factors in yand z-directions increase, while that in x-direction decreases.