Interface morphologies in polyolefin fiber reinforced concrete composites

Morphologies of fiber-matrix interface in polyolefin fiber reinforced concrete composite (FRC) and fiber surface were observed by using a scanning electronic microscope (SEM). Interfacial roughness, alternate bulges and grooves with breadth varying from less than 1 mu m up to 20 mu m, oriented along interface longitudinal direction. Fibrils and fiber chips, with either end or both ends, were anchored in matrix. Mo patch of fiber material stuck on the interface, after fiber was peeled away from interface, was found. Fiber surface was roughened along fiber axial direction during mixing in cementitious mix and abraded again during pullout. It is concluded that the interfacial roughness was formed due to fiber surface roughness, and I:he bond between polyolefin fiber and concrete matrix is mainly mechanical. (C) 1998 Elsevier Science Limited.