sinteredbut preferablycalcined hydraulic cement min 90 min 90 4 15 9 12with al sub 2 o sub 3 content lt 75 microns lt 75 micronsgreater than 75 __________________________________________________________________________ the present formulations are mixed with water in an amount adequate to yield a workable mix such a mix may for instance contain 7 water by weight of the mix formulations according to the invention are self setting at room temperature application of heat is unnecessary although moderate heating to accelerate curing of cast shapes may be permissible without heating however curing to a state allowing de moulding can be achieved within one hour or so thus high productivity can be achieved the present hydraulically bonding formulations possess significant advantages over chemically bonded systems a problem ever present with chemically bonded systems is that when they are in the process of heat setting and drying the binder tends to migrate to exposed surfaces bond migration and resulting non uniformity of the integrity of castings do not arise with the present formulations moreover a rigid set occurs with the present formulations so that handling of castings e g when de moulding it free from the risk of introducing internal stress flaws it is not impossible with chemically bound castings to adversely affect them during handling the present formulations have surprisingly excellent resistance to thermal shock they are therefore expected to find use in parts of sliding gate valves and associated pouring nozzles used in the intermittent teeming of molten metals e g steel during ingot casting for instance a commonly used test for thermal shock resistance is the torch test developed by u s steel corporation 39.