Fiber reinforced light-weight foamed mortar (air mortar) showing multiple cracking behavior was developed by means of adding prefoamed air bubble to fiber reinforced mortar including ECC (Engineered Cementitious Composites). The effects of air contents and fiber types, namely Polyethylene (PE) fiber, Polyvinylalcohol (PVA) fiber and Polypropylene (PP) fiber, on the properties such as compressive strength and ductility, the shape of flexural load-displacement curves, and the cracking behavior of the fiber reinforced light-weight foamed mortar were investigated. The continuous or discontinuous air bubbles and the pulled-out or ruptured fibers were observed by means of a digital microscope on the fractured surface of specimens after flexural tests. As a result, in the range of this study, the absorbed energy at fracture, which was indicated with the area under flexural load-displacement curves, was large in turn of PE>PVA>PP. In all three types of fibers, the air bubbles were discontinuous up to about 40% in the volume of air content. As increasing of the air content, the strength decreased, but both the flexural deformability and the multiple cracking behavior became remarkable.
