Abstract: There is provided in a pressure feed pipe for feeding cement paste under pressure a wall panel assembly formed of a plurality of wall panels having collision surfaces and through holes and arranged at predetermined intervals. High-strength or superhigh-strength mortar or concrete is produced by kneading a designed amount of binder material comprising cement or cement and a pozzolan material together with a predetermined amount of water, passing this cement paste through the abovementioned pressure feed pipe to crush the cement balls contained in the cement paste and thus to homogenize the paste, and kneading the thus homogenized cement paste together with fine aggregate or fine and coarse aggregates.