Composition and Method for Obtaining Exposed Aggregates in Surfaces of Moulded Concrete And Other Cementitious Materials

摘要

Surface retarder coating compositions of the invention are based on the use of at least one non-Ordinary Portland Cement (non-OPC) binder and at least one OPC set retarder agent, which are provided in powder form that can be mixed with water at the construction site. The coating is applied onto the surface of a mould or formwork using roller or spray equipment, and concrete can then be cast within 30-60 minutes against the coating. The OPC set-retarding agent operates to retard setting of the concrete so that it can be de-moulded the next day and its surface can be removed using a high pressure water spray to reveal aggregate embedded beneath the removed surface.

主权项

1. A composition for coating a mould or formwork and de-moulding cement and concrete materials cast therein, comprising:
a plurality of particles comprising
(a) at least one non-Ordinary Portland Cement (non-OPC) binder operative to form a coating when mixed with at least one inert filler and water to form a uniform mixture, said non-OPC binder being present in the amount of 1 to 95 percent;(b) at least one inert filler operative with said at least one non-OPC binder to form a coating when mixed with water and to harden upon the mould or formwork, said at least one non-OPC binder being present in the amount of 0 to 90 percent;(c) optionally at least one accelerator agent operative to accelerate the setting of said at least one non-OPC binder, said optional at least one non-OPC accelerator agent being present in the amount of 0 to 5.0 percent; and(d) at least one OPC set retarder agent operative to retard the setting of cement or concrete cast into the mould or formwork, said at least one OPC retarder agent being present in the amount of 0.5 to 40.0 percent;the foregoing percentages being based on total dry weight of the coating composition.