Moulding of construction products by vibration and pressure applications at relatively small intensities

A method for the manufacture of cored construction products comprising dry particulate materials, comprising the steps of providing a mould having at least one core former therein, vibrating the mould, with means operating substantially in the axial direction of the at least one core former, whilst progressively filling the mould with an appropriate mix of the materials, applying pressure to the materials in the mould in a direction transversely of the at least one core former, thereafter withdrawing the at least one core former to leave a corresponding core void, and then applying a sufficient quantity of setting liquid to a free surface of the materials to give full impregnation thereof by capillary action, wherein the vibration of the mould is at relatively small intensities to effect pre-compaction of the materials whereby individual particles of the materials are rearranged into substantially uniform, more closely spaced disposition sufficient that upon the subsequent application of said pressure the materials are brought into a final compacted state without substantial redistribution or local crushing of the particles.