Hydraulic and earth engineering – Foundation – Columnar structure
Reexamination Certificate
1999-06-08
2001-08-28
Neuder, William (Department: 3672)
Hydraulic and earth engineering
Foundation
Columnar structure
C405S257000, C428S411100
Reexamination Certificate
active
06280120
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a method for preventing adhesion of a hardened body of a hydraulic composition and a support body, the support body being intended to support the hydraulic composition from inside or outside the same at least while the hydraulic composition is being hardened, as well as related to a method for extracting a support body out of the hydraulic composition after the hydraulic composition is hardened, the support body being intended to support the hardened hydraulic composition from inside the same at least while the hydraulic composition is being hardened, the hydraulic composition being used for soil structure which is built in foundation constructing works in the civil engineering and construction fields. More specifically, the present invention relates to a method for suppressing adhesion between a support body and a hardened body of a hydraulic composition, and a method for extracting the support body therefrom, the methods being characterized in that a composition composed of at least an alkaline-water-soluble resin with an acid valve of not less than 15 mgKOH/g and an absorbent is used, to suppress adhesion between a support body such as H-shaped steel and a hardened body of a hydraulic composition such as a cement composition and to more easily separate the both from each other.
BACKGROUND OF THE INVENTION
In the fields of civil engineering and construction, in order to build a soil structure to be used as a structure like a retaining wall which is built in a foundation constructing work, (i) an H-shaped steel or the like, which is to serve as a support body (core) for supporting from inside a hardened body of a hydraulic composition formed by hardening the hydraulic composition such as cement milk or freshly mixed concrete, is preparatorily loosely inserted into a bore hole and the hydraulic composition such as cement milk or freshly mixed concrete is poured to around the H-shaped steel so as to be hardened (hydrated), or alternatively (ii) an H-shaped steel or the like as core is buried (driven) into a hydraulic composition which has been poured into a bore hole and thereafter the hydraulic composition is hardened (hydrated).
Examples of such building techniques include a peristylar soil cement continuous wall technique which is recently generally used for civil engineering works and construction works for high-rise building construction and such works in river and underground areas. In this technique, areas surrounding a construction site are bored and holes obtained by the boring are filled with a cement composition such as a soil cement milk so that soil cement walls for suppressing hydraulic pressure and earth pressure are constructed, in which H-shaped steels, for example, are used as cores. In earth retaining works as well, support bodies (cores) such as H-shaped steels are buried in a cement-based substance so as to form concrete walls.
Support bodies such as H-shaped steels thus buried in hydraulic compositions are in many cases unnecessary after finishing of the construction, and if the support bodies unnecessary are extracted from the hardened bodies of the hydraulic composition and collected so as to be re-used, it will be of advantage, from the viewpoints of saving of resource and environmental safeguards, and also will be very economical. Further, by extracting from the hardened bodies of hydraulic composition the support bodies which have become unnecessary after foundation constructing works finished, or separating portions of the hardened bodies in contact with the support bodies from the support bodies or removing the same therefrom, it will facilitate such secondary works as the expansion and the remodeling of existing buildings and the construction of sewerage systems and water supply systems.
Therefore, the support bodies such as H-shaped steels buried in the hydraulic composition are preferably extracted from the hardened bodies (hydrates) after the hardening of the hydraulic composition so as to be re-used, or are preferably extracted from the hardened bodies and removed, or made separable therefrom, so that they will not later obstruct redevelopment of the underground of the same site.
The support bodies (cores) thus buried and the hardened bodies of the hydraulic composition firmly bond with each other, and in order to separate the support bodies from the hardened bodies of the hydraulic composition and extract them, such a considerably great pulling force that may overwhelm bond strength (adhesive strength) is required (in many cases, extraction is impossible), resulting in that extra equipments, costs, and time for the separation are needed. As a result, the workability is inferior, a work of removal cannot be swiftly carried out. In addition, -:he support bodies (cores) such as H-shaped steels extracted out are consequently deformed, which are inappropriate for re-use.
Therefore, various methods for facilitating the foregoing extracting works have been conventionally proposed, which include (i) a method in which a lubricant such as wax or grease is preparatorily applied on a surface of an H-shaped steel, a method in which a water-absorbent resin is applied onto a surface of an H-shaped steel with use of an adhesive, (ii) a method in which a lubricating material is bonded on a surface of an H-shaped steel, and (iii) a method in which an H-shaped steel is covered with a covering member.
As the method of the above (i), the Japanese Publication for Laid-Open Patent Application No. 58715/1989 (Tokukaisho 64-58715 (date of publication: Mar. 6, 1989)) proposes that a surface processing agent for core-extraction use, which is made of a water-absorbent resin and a spreading agent such as a polyester-based resin, a vinyl-based resin, an acryl-based resin, or an urethane-based resin is used rather than the foregoing lubricant. The Japanese Publication for Laid-Open Patent Application No. 165615/1988 (Tokukaisho 63-165615 (date of publication: Jul. 8, 1988)) proposes a method in which a water-swelling film made of a water-absorbent resin and a volatile-film-forming resin such as natural rubber, synthetic rubber, or plastic is used, rather than the foregoing lubricant, so that frictional resistance upon extraction of a steel stock is reduced.
Furthermore, as the method of the above (ii), the Japanese Publication for Laid-Open Patent Application No. 185054/1994 (Tokukaihei 6-185054 (date of publication: Jul. 5, 1994)) proposes application of a sheet-like lubricating material made of superabsorptive fibers onto a surface of a steel stock. Further, for example, the Japanese Publication for Laid-Open Patent Publication No. 174418/1987 (Tokukaisho 62-174418 (date of publication: Jul. 31, 1987)) proposes that a lubricating tape made of a water-absorbent resin and a binder is used so that frictive resistance upon extraction of steel stocks is reduced.
Furthermore, as the method of the above (iii), the Japanese Publication for Laid-Open Patent Application No. 247549/1995 (Tokukaihei 7-247549 (date of publication: Sep. 26, 1995), corresponding to the European Patent Application No. 0663477A1 (date of publication: Jul. 19, 1995)) discloses a method in which a temporarily buried reinforcement is covered with a bag-shaped lubricating member composed of a polymer sheet which is produced by bonding a water-absorbent resin directly onto a substrate such as woven fabric or non-woven fabric without use of a bonding agent, so that frictive resistance upon extraction of the buried reinforcement is reduced.
However, the spreading agent contained in the surface processing agent which is proposed in the aforementioned Tokukaisho 64-58715, and the volatile-film-forming resin contained in the water-swelling film which is proposed in the aforementioned Tokukaisho 63-165615 are inferior in solubility in cement water contained in a hydraulic composition such as concrete, as well as inferior in swelling with respect to the same. Accordingly, both of the foregoing spreading agent and the foregoing volatile-film-forming resin hinder
Hattori Akira
Kadonaga Kenji
Masuda Yoshihiko
Murakami Yohei
Okamoto Kouichi
Conlin David G.
Dike, Bronstein, Roberts & Cushman Intellectual Property Group
Dougherty Jennifer R.
Neuder William
Nippon Shokubai Co. , Ltd.
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