Method for rapid hydration of cement and improved concrete
AssigneeLintek International, Inc.
InventorTung D. Lin
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Abstract
A method is described for making concrete from an initially dry mixture including Portland cement, a fine aggregate, and a coarse aggregate. The method is effective for curing mixtures which contain rubble, as well as for mixtures which contain primarily virgin aggregate. In the method, substantially dry steam is introduced to the mixture at elevated temperature and pressure. Air injection may be utilized to further increase the pressure. An improved concrete is also described. The concrete exhibits unexpectedly high compressive strength.
Claims17
A method for making concrete from an initially dry mixture including portland cement, a fine aggregate, and a coarse aggregate, which method comprises the steps of:
- introducing steam into the mixture, which steam contains less than 1% by weight of liquid phase water;
- maintaining the steam in contact with the mixture approximately at saturation conditions for a time effective to hydrate substantially all of the cement;
- and
- injecting air into contact with the mixture and with the steam, while the steam is being maintained in contact with the mixture, so as to make concrete having a compressive strength of at least about 69,000 kN/m.sup.2.
A method for recycling previously used material to make concrete, which method comprises the steps of:
- providing an initially dry mixture including portland cement, a fine aggregate, and a coarse aggregate being a comminuted, recycled material selected from the group consisting of demolished brick and broken concrete;
- and
- introducing steam into the mixture, which steam contains less than 1% by weight of liquid phase water;
- and
- maintaining the steam in contact with the mixture at approximately saturation conditions for a time effective to hydrate substantially all of the cement in the mixture, so as to make concrete having a compressive strength of at least about 35,000 kN/m.sup.2.
A concrete suitable for use as a building material, comprising:
- a fine aggregate;
- a coarse aggregate being a comminuted, recycled material selected from the group consisting of demolished brick and broken concrete;
- and
- a hydrated portland cement which is bound to the fine aggregate and to the coarse aggregate, wherein said concrete has a compressive strength of at least about 35,000 kN/m.sup.2.
A concrete suitable for use as a building material, comprising:
- a fine aggregate;
- a coarse aggregate;
- and
- a portland cement present in an amount in the range of about 250 to about 325 kilograms per cubic meter, as measured in a dry mixture of the fine aggregate, the coarse aggregate, and the portland cement before hydration of the portland cement, the portland cement having been hydrated by contact with dry steam containing less than 1% by weight of liquid phase water;
- said concrete having a compressive strength of at least about 62,000 kN/m.sup.2.
A method for making concrete suitable for use as a building material, which method comprises the steps of
- providing an initially dry mixture of a fine aggregate, a coarse aggregate, and portland cement, which portland cement is present in an amount in the range of about 250 to 325 kilograms per cubic meter of the initially dry mixture, and
- hydrating the portland cement in the dry mixture by contact with steam containing less than 1% by weight of liquid phase water so as to produce concrete having a compressive strength of about 62,000 kN/m.sup.2.
Dependencies are inferred from the claim text.