Compositions: coating or plastic – Coating or plastic compositions – Inorganic settable ingredient containing
Reexamination Certificate
1999-11-12
2003-09-09
Wood, Elizabeth D. (Department: 1755)
Compositions: coating or plastic
Coating or plastic compositions
Inorganic settable ingredient containing
C106S717000, C106S719000, C106S724000, C106S727000, C106S802000, C106S806000, C106S823000
Reexamination Certificate
active
06616755
ABSTRACT:
This invention relates to a self-levelling concrete enabling to eliminate completely vibrations and surface finishing, as well as to a method for making a structural part from the said concrete, whereas the manufactured parts can be vertical as well as horizontal.
The self-levelling concretes are very fluid concretes than can be placed and tightened under the alone effect of gravity without calling for any vibrations. The self-levelling concretes also produce after hardening a homogeneous end product, which has not undergone any segregation. A description of such concretes can be found in the bibliographic synthesis by Thierry SEDRAN published in Bull.-Labo. P. and Ch., 196, ref. 3889, March-April 1995. A comment of these concretes can also be found in the article by NAGATAKI, <<Concrete Technology in Japan>> (chapter 3), published in Concrete Under Severe Conditions: Environment and Loading (Volume 1), edited by. K. SAKAI, N. BANTHIA and O. E. GJORV, 1995.
The self-levelling concretes notably and advantageously produce materials of a quality not so dependent on the workers' know-how and the quality concrete as well as better steel coating, reduce the implementation durations and the necessary labour during casting, and improve ergonomy.
However surface defects frequently appear, especially macrobubbling.
This invention relates to a self-levelling concrete enabling to obtain better quality facing, avoiding macrobubbling and not requiring any surface finishing.
The invention also relates to such a self-levelling concrete, providing good rheology handling, can be cheap, enables using any cement amongst a wide variety of cements and can be manufactured in a ready-mix concrete plant thanks to a few hours' rheology handling.
The invention also relates to a method for making a structural part from a self-levelling concrete, easy to be implemented, not requiring any cranes, thus providing time to enhance productivity of the building yard and particularly suited for a self-levelling concrete exhibiting the previous qualities.
In the following, the value ranges are inclusive.
The invention applies to a self-levelling concrete of known composition, comprising in weight, for cubic meter of concrete:
about 350 to 600 kg/m
3
of binder, of which 200 to 500 kg/m
3
are cement,
about 170 to 250 kg/m
3
of water,
about 0.5 to 4 kg m
3
of various agents and additives (dry extracts), comprising at least one superplasticizer,
the cubic meter supplement, in weight, of granulates and solid particles of size smaller than or equal to 12 mm, preferably smaller than or equal to 8 mm.
According to the invention, the superplasticizer is a hydrosoluble or hydrodispersible organic compound, which comprises at least one amino-di-(alkylene phosphonic) group, optionally as a salt, and at least one polyoxyalkylated chain. More precisely, the superplasticizer is a compound (I) or a salt of said compound (I), wherein this compound has the formula.:
in which:
R is a hydrogen atom or a saturated or unsaturated monovalent hydrocarbon group, comprising 1 to 18 carbon atoms and optionally one or several heteroatoms: R being preferably a hydrogen atom or a monovalent saturated or unsaturated hydrocarbon group comprising 1 to 4 carbon atoms, 50% to 100% of the Ri are ethylene, 0 to 50% of the optional other Ri are similar or different from one another and represent an alkylene such as ethylene, propylene, butylene, amylene, octylene or cyclohexene, or an arylene such as styrene or methylstyrene; whereby the Ri may include one or several heteroatoms,
Q is a hydrocarbon group comprising 2 to 18 carbon atoms and optionally one or several heteroatoms,
A is an alkylidene group comprising 1 to 3 carbon atoms, A representing preferably the methylene group,
The Rj are similar or different from another and can be selected from
the A—PO
3
H
2
group, whereas A has the meaning mentioned above,
and the group
B designating an alkylene group comprising 2 to 8 carbon atoms, B representing preferably ethylene or propylene, A having the above mentioned meaning,
<<n>> is a number ranging from 20 and 250,
<<r>> is the number of [R—O(R
i
—O)
n
] groups of Rj,
<<q>> is the number of [R—O(R
i
—O)
n
] groups of Q,
the sum <<r+q>> should not exceed 3
<<y>> is an integer equal to 1 or 2,
Q, N and the Rj may form together one or several rings, whereas this or these rings may also comprise one or several other heteroatoms.
The salts of the compounds (I) can be stoichiometric or not, mixed or not and consist of alkaline metals, alkaline-earth metals, amines or quaternary ammoniums.
The form of the compounds (I) may vary from liquid to solid, while passing through the wax phase.
The supplement to cement to make up the binder advantageously consists of ground high furnace slag, volatile ashes, filler, calcareous or siliceous or other puzzolanic elements.
The category of the superplasticizers of the self-levelling concrete according to the invention is known in itself generally as a fluidising component for aqueous suspensions of mineral particles and hydraulic binder pastes, and is disclosed in the document FR-A-2.696.736. Moreover, a method for preparing such a fluidising component is described in the document FR-A-2.689.895. However, the use of this fluidising component as a superplasticizer in a self-levelling concrete according to the invention is new. We refer notably to the document FR-A-2,696.736 for a detailed description of the category of the compounds (I) and of the salts of said compounds (I) used as superplasticizers the self-levelling concrete according to the invention.
The self-levelling concrete according to the invention exhibits surprising results, which provide decisive advantages:
a) it avoids macrobubbling while allowing the bubbles to float up to the surface and thus provides facings of very smooth surface and superior quality, not requiring any surface finishing at a later stage;
b) it practically exhibits neither segregation nor exudation phenomenon, which consequently enables to avoid the requirement to add a viscosity agent and thus provides cost savings and easier implementation;
c) the cement contained in the self-levelling concrete according to the invention can be selected from a very wide variety of cements without affecting the qualities of the concrete significantly;
d) the facing obtained is clear or becomes clear rapidly (for example after a week) in quite numerous cases, even in the presence of a large quantity of volatile ashes or of dark cement, which provides the facing with higher aesthetic quality;
e) the concrete exhibits good rheology handling, which may generally last 3 hours at least.
The self-levelling concrete according to the invention may also enable vibration-less implementation, practically no exudation, rapid implementation, good pumping capacity and very good vibration-less horizontal levelling property. The concrete can be prepared in a conventional ready-mix plant without modification of this ready-mix plant and can be delivered, ready for use, by mixer trucks to the building yard. If needed, fluidity of the concrete is adjusted by complementary addition of the superplasticizer on the building yard. Thus, the doses of each component of the concrete can thus be regular.
Fluidity of the concrete removes traditionally slumping and levelling operations with a rule or an equivalent means, as well as the floating operation for horizontal concrete works, providing the man of the art adheres to the normal implementation conditions. To obtain a plane and smooth horizontal surface, it suffices to apply slowly a finishing bar over the surface of the fresh product. Indeed, concrete is almost self-smoothing. Besides, maintaining this fluidity for a reasonable duration, from 2 to 4 hours and good setting and hardening kinetics of the concrete, enable people to tread upon the manufactured part as soon as the day following the pouring of the concrete.
During slump flow tests, this concrete enables o
Garcia Rémy
Levy Christophe
Arent Fox Kintner & Plotkin & Kahn, PLLC
Lafarge Platres
Wood Elizabeth D.
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