Hydraulic cement compositions and additives therefor

Details Hydraulic cement compositions and additives therefor Hydraulic cement compositions and additives therefor

2001-07-30

2002-09-24

Marcantoni, Paul (Department: 1755)

Compositions: coating or plastic

Coating or plastic compositions

Inorganic settable ingredient containing

C106S724000, C106S727000, C106S823000

Reexamination Certificate

active

06454849

ABSTRACT:

BACKGROUND OF THE INVENTION
This invention relates to hydraulic cement compositions and additives therefor. It is important to improve the durability of objects obtained by hardening a hydraulic cement composition such as mortars and concrete, and it is particularly so if such hardened objects are to be used as base or skeletal materials in a civil engineering and constructional project. Among the commonly known causes of lowering the durability of a hardened object obtained from a hydraulic cement composition are (1) the weakening of the surface layer of the hardened object due to bleeding of water after the placing of hydraulic cement composition, (2) the cracking of the hardened object due to dry shrinkage, and (3) the destruction of the hardened object due to freezing and thawing in cold places. In order to improve the durability of hardened objects obtained by hardening a hydraulic cement composition, it is necessary to inhibit the occurrence of such causes. It is therefore an object of this invention to provide additives for hydraulic cement compositions for inhibiting the occurrence of these causes for lowering the durability of such hardened objects.
Examples of earlier proposed additives for hydraulic cement compositions for inhibiting the occurrence of causes for lowering the durability of such hardened objects include (1) polyalkyleneglycol alkylether or polyalkyleneglycol cycloalkylether (as disclosed in Japanese Patent publications Tokko 56-51148 and 59-3430 and U.S. Pat. No. 4,547,223), (2) aliphatic or alicyclic alcohol with 4 or 5 carbon atoms (as disclosed in Japanese Patent Publication Tokko 6-6500 and U.S. Pat. No. 5,181,961), (3) organic esters of phosphoric acid such as alkyl phosphoric acid ester, polyoxyethylene alkylether phosphoric acid ester and polyoxyethylene alkylphenylether phosphoric acid ester (as disclosed in Japanese Patent Publication Tokko 53-37251), and (4) compositions comprised of polypropyleneglycol with average molecular weight of 100-800, alkyl phosphoric acid ester and an antifoaming agent (as disclosed in Japanese Patent Publication Tokko 1-23430 and U.S. Pat. No. 5,938,835). Although these earlier proposed additives are fairly effective in reducing the drying shrinkage of hardened objects or making hardened objects more resistive against freezing and thawing, their effects are not sufficiently manifested, in particular for inhibiting the bleeding after the placing which causes the weakening of the surface layer of a hardened object.
SUMMARY OF THE INVENTION
It is therefore an object of this invention to provide an additive for hydraulic cement compositions capable of not only sufficiently reducing the bleeding of water after the placement of a hydraulic cement composition and the drying shrinkage of hydraulic cement compositions but also providing sufficient resistance to hardened objects against effects of freezing and thawing.
This invention is based on the inventors' discovery as a result of research carried out in view of the above that such object can be achieved with additives consisting of four specified components at specified ratio.
DETAILED DESCRIPTION OF THE INVENTION
The invention relates to additives for hydraulic cement compositions characterized as comprising 5-95 weight % of Component A described below, 5-95 weight % of Component B described below, 0.1-10 weight % of Component C described below and 0.01-2 weight % of component D described below for a total of 100 weight %, where Component A is (poly)ethyleneglycol monocycloalkylether shown by Formula 1 given below, Component B is (poly)alkyleneglycol or (poly)alkyleneglycol monoalkylether shown by Formula 2 given below, Component C is an organic phosphoric acid ester given by Formula 3 or Formula 4 given below, and Component D is an antifoaming agent, wherein
R
1
—(OCH
2
CH
2
)
n
—OH  Formula 1
R
2
—O—A
1
—OH  Formula 2
wherein R
1
is cyclopentyl group or cyclohexyl group, R
2
is H or alkyl group with 1-6 carbon atoms, R
3
and R
4
are each alkyl group with 8-18 carbon atoms, A
1
is a residual group obtained by removing all hydroxyl groups from (poly)ethyleneglycol having (poly)oxyethylene group composed of 1-4 oxyethylene units, residual group obtained by removing all hydroxyl groups from (poly)propyleneglycol having (poly)oxypropylene group composed of 1-10 oxypropylene units, or residual group obtained by removing all hydroxyl groups from polyalkyleneglycol having polyoxyalkylene group composed of a total of 2-14 oxyethylene units and oxypropylene units, A
2
is (poly)oxypropylene group with 1-5 oxypropylene units, M
1
, M
2
, M
3
and M
4
are each H, alkali metal, alkali earth metal, ammonium or organic amine, and n is an integer 1-5. The invention also relates to hydraulic cement compositions characterized as having 0.5-10 weight parts of such an additive added to 100 weight parts of cement.
Aforementioned Component A according to this invention is (poly)ethyleneglycol monocycloalkylether shown by Formula 1. Examples of such (poly)ethyleneglycol monocycloalkylether include (1) ethyleneglycol monocyclopentylether with one oxyethylene unit in its molecule, (2) polyethyleneglycol monocyclopentylether with ethyleneglycol monocyclohexylether with one oxyethylene unit in its molecule, and (4) polyethyleneglycol monocyclohexylether with polyoxyethylene group composed of 2-5 oxyethylene units in its molecule. Particularly preferable among these are (poly)ethyleneglycol monocyclopentylether and (poly)ethyleneglycol monocyclohexylether with (poly)ethylene group composed of 1-3 oxyethylene units in the molecule.
Aforementioned Component B according to this invention is (poly)alkyleneglycol or (poly)alkyleneglycol monoalkylether shown by Formula 2. Examples of such (poly)alkyleneglycol include (1) (poly)ethyleneglycol with (poly)oxyethylene group composed of 1-4 oxyethylene units in the molecule, (2) (poly)propyleneglycol with (poly)oxypropylene group composed of 1-10 oxypropylene units in the molecule, and (3) polyalkyleneglycol with polyoxyalkylene group composed of a total of 2-14 oxyethylene units and oxypropylene units in the molecule. Examples of (poly)alkyleneglycol monoalkylether include (4) (poly)ethyleneglycol monoalkylether obtained by closing one end of (poly)ethyleneglycol of (1) with alkyl group with 1-6 carbon atoms, (5) (poly)propyleneglycol monoalkylether obtained by closing one end of (poly)propyleneglycol of (2) with alkyl group with 1-6 carbon atoms, and (6) polyalkyleneglycol monoalkylether obtained by closing one end of polyalkyleneglycol of (3) with alkyl group with 1-6 carbon atoms. In the cases of (3) and (6), the combination mode of oxyethylene and oxypropylene units may be either random combination or block combination. Particularly preferable among the above is polyalkyleneglycol monoalkylether with polyoxyalkylene group composed of a total of 4-13 oxyethylene units and oxypropylene units in the molecule.
Aforementioned Component C according to this invention is organic phosphoric acid ester shown by Formula 3 or Formula 4. Examples of organic phosphoric acid ester shown by Formula 3 include alkyl phosphoric acid monoesters where M
1
and M
2
in Formula 3 are both H, their alkali metal salts, their alkali earth metal salts, their ammonium salts and their organic amine salts, all having alkyl group with 8-18 carbon atoms. Examples of organic phosphoric acid ester shown by Formula 4 include (poly)oxypropylene monoalkylether phosphoric acid monoesters where M
1
and M
2
in Formula 4 are both H, their alkali metal salts, their alkali earth metal salts, their ammonium salts and their organic amine salts, all having alkyl group with 8-18 carbon atoms and (poly)oxypropylene group composed of 1-5 oxypropylene units in the molecule. Particularly preferable among them are alkali metal salts of polyoxypropylene monoalkylether phosphoric acid monoesters which are organic phosphoric acid esters shown by Formula 4, having alkyl group with 10-16 carbon atoms and (poly)oxypropylene group composed of 1-5 oxypropylene units in the

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