In order to propose a method for predicting extruding pressure under extrusion moulding of cementitious components, mortars with various water content ratios and two kinds of fiber additives were extruded by extruders with different barrel diameters using various kinds of die opening geometries including the alternation of width, thickness and hollow ratio. It was verified that the effective thickness law was available, because the unique relationships between extruding pressure and effective thickness, which meant the transformation grade of mixtures, were obtained. Based on the law and plastic processing one, the comprehensive flow for predicting extruding pressure only through a single shear test was proposed.
