Abstract: A method for manufacturing a concrete article is disclosed. The method comprises coating a mould or formwork with a release agent; spraying a mortar onto the mould or formwork, thereby forming a layer of mortar; casting concrete into the mould or formwork and onto the layer of mortar; and allowing the concrete to hydrate and harden in the mould or formwork, whereby a concrete article having a mortar skin layer is provided. The invention also provides concrete articles made by the described methods, and concrete structures which comprise the concrete articles. Concrete articles having the mortar skins can be made to have a relatively uniform outward appearance, even if the concrete cast behind the mortar skins may be different, in composition or appearance. Pigments or colorants and other expensive admixtures can be used in the mortar skin composition to greater visual effect, since the use of the mortar skin is less in overall volume compared to the concrete articles as a whole.

Abstract: Disclosed are surface retarder composition and method for etching cementitious materials which achieve a desirable light “acid etch” look without using muriatic (hydrochloric) acid or sand blasting, removing the human health and environmental concerns. Formulations in accordance with embodiments disclosed herein are easier to remove from formwork or molds after demolding than conventional retarder paints. Surface retarders prevent the hydration of cement particles, which allows the uncured layer of paste next to the form to be removed such as by washing with water or other fluids, or by brushing, revealing aggregates. Also disclosed are molded cement and concrete materials or articles exhibiting such light etch.

Abstract: 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.

Abstract: 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.

Abstract: Exemplary methods and compositions of the invention for retarding the surface of a hydratable cementitious composition comprise the use of a non-bituminous cationic emulsion comprising at least one curing compound comprising an acrylic polymer, a paraffin, or a mixture thereof, to hinder evaporation of water; at least one set retarder; and at least one cationic surfactant.

Abstract: Exemplary methods and compositions of the invention for retarding the surface of a hydratable cementitious composition comprise the use of a non-bituminous cationic emulsion comprising at least one curing compound comprising an acrylic polymer, a paraffin, or a mixture thereof, to hinder evaporation of water; at least one set retarder; and at least one cationic surfactant.

Abstract: An exemplary method for set retarding the surface of a mortar or concrete material, comprising applying to the surface of a mortar or concrete, or to the inner surface of a mold for forming the mortar or concrete, a hot melt coating composition which is heated to assume a flowable or sprayable form, and allowing the hot melt coating composition to cool to ambient temperature whereby the composition forms a solidified membrane, and thereafter removing the membrane. Preferably, the hot melt coating composition contains at least one agent operative to retard the setting of the mortar or concrete, and optional finely divided particulate materials, light-reflective pigments, or mixtures thereof.

Abstract: Compositions and methods of the invention for retarding the surface of a concrete or other hydratable cementitious composition involve the use of at least one alkyl-ester-of-hydroxycarboxy compound contained in the form of particles or as a discontinuous phase distributed within a continuous non-aqueous carrier phase that is spray-applicable in liquid form. The set retarder helps to achieve lower pH and to avoid irritating fogs during spray application of the surface retarder when compared to prior art acid-containing surface retarders.

Abstract: An exemplary method for set retarding the surface of a mortar or concrete material, comprising applying to the surface of a mortar or concrete, or to the inner surface of a mold for forming the mortar or concrete, a hot melt coating composition which is heated to assume a flowable or sprayable form, and allowing the hot melt coating composition to cool to ambient temperature whereby the composition forms a solidified membrane, and thereafter removing the membrane. Preferably, the hot melt coating composition contains at least one agent operative to retard the setting of the mortar or concrete, and optional finely divided particulate materials, light-reflective pigments, or mixtures thereof.

Abstract: Surface retarder compositions of the invention comprise at least one surface retarder active suspended in a vegatable oil or derivative thereof, an animal oil or derivative thereof, or mixtures thereof. Methods involving use of the compositions are also described.

Abstract: Surface retarder compositions of the invention comprise at least one surface retarder active suspended in a vegatable oil or derivative thereof, an animal oil or derivative thereof, or mixtures thereof. Methods involving use of the compositions are also described.