Rexural strength and its determining factors of advanced fiber reinforced cementitious materials produced by extrusion moulding are experimentally examined. Densifying mechanism is specially focused under extrusion moulding production in case of using new types of high strength fibers. Density was observed to be much related to flexural strength and independent of mechanical properties of fibers. The way to densify this type of materials under production is clarified to be fundamental for producing strong cementitious materials by extrusion moulding. It is also verified that total void ratio including water content to cement is effective for predicting the flexural strength of extruded cement mortar with fibers.
