Compositions: coating or plastic – Coating or plastic compositions – Inorganic settable ingredient containing
Reexamination Certificate
2000-05-16
2003-11-11
Marcantoni, Paul (Department: 1755)
Compositions: coating or plastic
Coating or plastic compositions
Inorganic settable ingredient containing
C106S713000, C106S714000, C106S715000, C106S718000, C106S719000, C106S724000, C106S726000, C106S735000, C106S820000, C106S823000
Reexamination Certificate
active
06645289
ABSTRACT:
This application is the National Phase Filing of PCT International Application No. PCT/TR98/00008, filed May 26, 1997, published Dec. 3, 1998, as Publication No. WO 98/54108, the full disclosures of which are incorporated by reference herein.
BACKGROUND OF INVENTION
1. Field of the Invention
The present invention relates to admixtures production and to method of the admixtures application in cement and concrete technology. The method allows to produce high-strength and high durable cement based systems, as well as cement systems with specially designed properties or cheap high-volume mineral admixture cements.
2. Description of the Prior Art
The admixtures for cement systems, especially high range water reducers or superplasticizers, have significant influence on strength and durability of concrete due to ability to reduce water demand and provide low porosity and permeability. The usage of such admixtures allows to produce concrete with high level of properties. The application of new high range water reducing agents for production of ultra high-strength concrete is explained in some U.S. patents (U.S. Pat. No. 5,466,289). Advantages of the high strength and high durable concrete have provided their large-scale applications in construction projects such as high-rise buildings, bridges, marine and offshore structures, tunnels, parking desks, repairing of structures, etc.
There are many products marketed as high range water reducers for concrete. The original composition of high range water reducers is protected by numbers of International patents (for instance, in U.S. Pat. No. 5,584,920; 5,494,516; 4,704,415; 4,460,720 and 4,441,929) and it is well-known that essentially they are lignosulphonates-, melamine-, naphthalene- and polyacrylate-based compounds. The process of water reduces production is realised in aqueous solution and the final product contains 55-75% of water. Application of water reducers in aqueous solution is impossible for some dry production process, such as cement and dry mortar. Usage of dry or semi-dry water reducers is more attractive for ready mix and precast concrete plant or construction site due to the reason of easy transportation and storage. For such projects dry powder water reducers are available. Production cost of the powder admixtures rises up to two times because drying process in special apparatus is used to remove water. Development of the cheapest process for the dry- or semi-dry water reducing admixtures would be useful to extend the frames of their application.
Process explained in U.S. Pat. No. 4,297,309 (except final procedure of firing) that allow to produce articles with different shape based on fine silica particles and water is very close to present invention. Application of active calcium reactive sorbents for combining of some gas and liquid chemicals, especially for sulfur dioxide and metals, is also described in some U.S. patents (U.S. Pat. No. 5,405,535; 5,227,351). Usage of invented complex admixture in cement and concrete technology is similar to existing mode for mineral admixtures such as fly ash (U.S. Pat. No. 5,601,643) application.
The main difference of the present invention is ability to create economical combinations in sorbent—water reducer system that can be used as universal and super effective modifiers for cement systems. The available test results confirm that synergetic effect of sorbent—water reducer is multiplied in case of increasing of preliminary treatment of cement—invented modifier compositions in dry or liquid state. This advantages allow to achieve new level of properties or provide production of wide range of new and more economic cement based materials with conventional properties.
SUMMARY OF THE INVENTION
The present invention is directed to development of the dry and semi-dry admixtures composition and production process. The usage of active silicon dioxide based sorbents allows to combine water containing in water reducers and to produce new complex admixture for modifying of cement system. The main criterion of sorbents selection is compatibility with cement system, especially for long-term action. The correct combinations in sorbent—water reducer system allows to create wide range of universal and super effective modifiers for cement systems.
The method of the complex admixture application in cement and concrete technology allows to produce the high-strength and high durable cement based systems, as well as the cement systems with specially designed properties or cheap high-volume mineral admixtures cements. The method is based on modification of cement or dry mix in production process by invented complex admixtures. This allows to increase the compressive strength of cement based materials up to 145-180 MPa and/or to introduce a large quantity of mineral indigenous admixtures up to 70% in the cement composition.
DETAILED DESCRIPTION OF THE INVENTION
The dry or semi-dry complex admixtures production process includes mixing of water reducer solution with powder components of active sorbents.
The most important component of the sorbent is presented by fine alkali reactive silicon dioxide based materials. Virtually any composition that includes fine or superfine non-crystalline silicon dioxide may be applied in the practice. Such compositions include, but are not limited by fly ash, rice husk ash, zeolite, silica fume, bentonite, activated kaolin, montmorillonite, diatomaceous earth, etc. The mass ratios of reactive silicon dioxide component to water reducer ranging from about 5:1 to about 100:1 are preferred.
Available high range water reducers, as well as their mix (including other admixtures) can be used. The best results are achieved in case of sulphonated melamine (SMF) or naphthalene (SNF) formaldehyde, as well as polyacrylate (PA) based high range water reducer application. The water content of high range water reducer component can be varied from about 25 to about 85%.
The high porous lightweight sand (with particles size less than 5 mm) can be used as water accumulating component of active sorbent. The wide range of natural and artificial lightweight materials, as volcanic pumice, tuff, expanded clay, expanded perlite, expanded slag, expanded glass, etc can be used. The mass ratios of reactive silica to accumulating porous component can be varied from about 10:1 to about 1:1.
The non-organic or organic salts or hydroxides of metals can be used as electrolytic agent, which provide better distribution and dissolving of the complex admixture particles in aqueous media. Such compositions include, but are not limited by metal (especially, alkali and alkali earth) aluminates, hydroxides and carbonates: sodium nitrite, sulphate Al, Na, K, Ca, calcium chloride, calcium formate, etc. The introduction of the electrolytic agent into process can be made before or together with reactive silica component mixing in order to provide better homogenisation of system. The mass ratios of reactive silica component to electrolytic agent can be varied from about 10:1 to about 1000:1. Accelerating effect on cement hardening process can be achieved in case of the composition application.
The hydrated, partially hydrated and dehydrated salts or combinations that are able to combine with water can be used to bond free water in the system. The water-combining component can be applied before, during or after mixing of the main composition. The last case provides the formation of the granules covered by dense protective layer. This solution may be very useful if total amount of water is high and due to some reasons reactive silica content can not be increased. The one or more types of calcium sulfate, high alumina cement or sulphate Na can be used as water combining component. The mass ratios of reactive silica to water combining component can be adjusted from about 1:1 to about 100:1. The effect of regulation of cement setting time, as well as accelerating of hardening process can be achieved for such composition.
The complex admixture can contain water-soluble polymer, which can be applied at any time during the m
Sobolev Konstantin
Soboleva Svetlana
Blank Rome LLP
Marcantoni Paul
Sci Con Technologies, Inc.
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