Tomographic analysis of segregation behavior of hollow glass microspheres in lightweight cementitious composites

Lightweight concrete must contain lightweight aggregates that are more susceptible to segregation than traditional concrete. Concrete has increasingly used lightweight fillers but research on segregation analysis is relatively scarce. To systematically investigate the segregation of hollow glass microspheres (HGMs), lightweight cementitious composites (LWCC) with a water-to-cement (w/c) ratio of 0.25-0.5 were investigated. The 3D structure of HGMs in the LWCC was observed with micro-computed tomography (mu-CT), and a rapid CT projection analysis was proposed to evaluate the segregation. The results showed that a slight segregation tendency of HGMs was observed from 0.45, while severe floating segregation occurred at 0.5 of w/c. The flowability of the LWCC increased with the increase of the w/c ratio, but it could not anticipate the segregation behavior. Meanwhile, 2D CT projection image could quickly evaluate the segregation phenomenon so it was proposed that it can be utilized for evaluating potential segregation of cement-based materials.