U.S. patent application number 14/395603 was filed with the patent office on 2015-05-14 for method for treating clay and clay-bearing aggregates and compositions therefor.
The applicant listed for this patent is L'Beste Gat Ltd., W R Grace & Co.-Conn.. Invention is credited to Lawrence Kuo, O-il Kwon, Ho Lee, Nathan Tregger.
Application Number | 20150133584 14/395603 |
Document ID | / |
Family ID | 48407495 |
Filed Date | 2015-05-14 |
United States Patent
Application |
20150133584 |
Kind Code |
A1 |
Kuo; Lawrence ; et
al. |
May 14, 2015 |
Method For Treating Clay And Clay-Bearing Aggregates And
Compositions Therefor
Abstract
The present invention provides compositions and methods
involving the use of a carboxylate graft polymer having high
molecular weight and low ratio of acid-to-polyoxyalkylene groups.
Such clay-mitigation is particularly useful for treating clay and
clay-bearing aggregates, particularly those aggregates used for
construction purposes. The present invention minimizes the need to
wash the aggregates, thus preserving fine aggregates ("fines")
content in construction materials, and thereby beneficiating the
performance and/or properties of construction materials containing
the clay-bearing aggregates.
Inventors: |
Kuo; Lawrence; (Acton,
MA) ; Tregger; Nathan; (Billerica, MA) ; Lee;
Ho; (Gyeonggi-do, KR) ; Kwon; O-il;
(Gyeonggi-do, KR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
W R Grace & Co.-Conn.
L'Beste Gat Ltd. |
Columbia
Kangnam-Gu, Seoul |
MD |
US
KR |
|
|
Family ID: |
48407495 |
Appl. No.: |
14/395603 |
Filed: |
May 3, 2013 |
PCT Filed: |
May 3, 2013 |
PCT NO: |
PCT/EP2013/059303 |
371 Date: |
October 20, 2014 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61642665 |
May 4, 2012 |
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Current U.S.
Class: |
524/5 ; 524/445;
524/547; 524/555; 524/560; 524/72; 525/154; 525/328.5; 525/328.9;
525/54.2 |
Current CPC
Class: |
C04B 24/305 20130101;
C08F 265/06 20130101; C08F 265/04 20130101; C04B 24/267 20130101;
C04B 14/06 20130101; C04B 2103/30 20130101; C04B 20/02 20130101;
C04B 2103/32 20130101; C04B 24/24 20130101; C08F 290/142 20130101;
C04B 24/283 20130101; C04B 14/10 20130101; C08K 3/346 20130101;
C04B 24/30 20130101; C04B 20/023 20130101; C04B 24/2647 20130101;
C04B 40/0039 20130101; C04B 24/023 20130101; C04B 2103/0059
20130101; C09K 8/467 20130101; C08F 220/286 20200201; C08F 220/06
20130101; C04B 40/0039 20130101; C04B 24/2647 20130101; C04B 24/267
20130101; C04B 2103/10 20130101; C04B 2103/20 20130101; C04B
2103/30 20130101; C04B 2103/40 20130101; C04B 2103/50 20130101;
C04B 20/023 20130101; C04B 14/10 20130101; C08F 220/286 20200201;
C08F 220/06 20130101 |
Class at
Publication: |
524/5 ;
525/328.9; 525/328.5; 524/445; 524/560; 524/555; 524/547; 524/72;
525/154; 525/54.2 |
International
Class: |
C04B 24/26 20060101
C04B024/26; C08K 3/34 20060101 C08K003/34; C04B 14/10 20060101
C04B014/10; C04B 24/30 20060101 C04B024/30; C04B 24/28 20060101
C04B024/28; C08F 265/04 20060101 C08F265/04; C04B 24/02 20060101
C04B024/02 |
Claims
1. A carboxylate graft polymer composition for treating clay or
clay-bearing aggregates, comprising: (A) a first component
represented by the following structure: ##STR00007## wherein
R.sup.1, R.sup.2, and R.sup.3 each independently represent
hydrogen, C.sub.1-C.sub.3 alkyl, --COOH, --CH.sub.2COOH, or
mixtures thereof; X represents hydrogen or an alkali metal; and (B)
a second component represented by the following structure:
##STR00008## wherein R.sup.4, R.sup.5, R.sup.6, R.sup.7, and
R.sup.8 each independently represent hydrogen, C.sub.1-C.sub.3
alkyl, --COOH, or mixtures thereof; Y represents --O--, --COO--,
--OOC--, --COHN--, or --NHCO--; Z represents (CH.sub.2).sub.n
wherein "n" represents a whole number of 0 to 6; and "m" represents
an integer of 25 to 200; (C) optionally a third component
comprising a repeating unit of polymerized (meth)acrylamide,
N-alkyl (meth)acrylamide, N,N-dialkyl (meth)acrylamide,
3-acrylamido-2-methylpropane sulfonic acid or its salts, and
styrene sulfonic acid or its salt, or mixtures thereof; and wherein
the molar ratio of said first component A to said second component
B is in the range of 50:100 to 100:40 and the weight-average
molecular weight of the carboxylate graft polymer is in the range
of 22,000 to 250,000; and wherein, if the molar ratio of said first
component A to said second component B is greater than 100:55, then
the weight-average molecular weight of the carboxylate graft
polymer is in the range of 70,000 to 250,000.
2. The carboxylate graft polymer composition of claim 1 further
comprising at least one repeating unit of a polymerized
(meth)acrylamide, N-alkyl (meth)acrylamide, N,N-dialkyl
(meth)acrylamide, 3-acrylamido-2-methylpropane sulfonic acid or its
salts, and styrene sulfonic acid or its salt, or mixtures
thereof.
3. The carboxylate graft polymer composition of claim 1 or 2
wherein said molar ratio of said component A to said component B is
between 0.6 and 1.8.
4. The carboxylate graft polymer composition of claim 3 wherein
said molar ratio of said component A to said component B is between
0.7 and 1.5.
5. The carboxylate graft polymer composition of any preceding claim
wherein the weight-average molecular weight of said carboxylate
graft polymer composition is in the range of 70,000 to 150,000.
6. The carboxylate graft polymer composition of any preceding claim
wherein the number-average molecular weight of said component B is
in the range of 1,000 to 10,000.
7. The carboxylate graft polymer composition of claim 6 wherein the
number-average molecular weight of said component B is in the range
of 1,500 to 7,500.
8. The carboxylate graft polymer composition of claim 7 wherein the
number-average molecular weight of said component B is in the range
of 2,000 to 5,000.
9. The carboxylate graft polymer composition of any preceding claim
wherein, when mixed into a plastic hydratable cementitious
composition, has a slump of 0-4 (using standard slump cone in
accordance with ASTM C143).
10. An aggregate composition comprising a plurality of clay-bearing
aggregates and the carboxylate graft polymer composition of any
preceding claim.
11. The aggregate composition of claim 10 wherein said plurality of
clay-bearing aggregates natural or manufactured sand, crushed
stone, crushed gravel, crushed rock, crushed shale, or mixtures
thereof.
12. The aggregate composition of claim 10 or 11 further comprising
a cementitious binder.
13. The aggregate composition of claim 10, 11 or 12 wherein said
carboxylate graft polymer is contained in said plurality of
clay-containing aggregates in an amount of 0.1% to 100% by weight
based on dry weight of clay contained in said plurality of
aggregates.
14. The aggregate composition of claim 13 wherein said carboxylate
graft polymer is contained in said plurality of clay-containing
aggregates in an amount of 1% to 50% by weight based on dry weight
of clay contained in said plurality of aggregates.
15. An admixture composition for modifying a cementitious
composition, comprising: (i) at least one chemical admixture
selected from the group consisting of water-reducing agent, set
retarders, set accelerators, air entraining agents, air detraining
agents, and mixtures thereof; and (ii) A carboxylate graft polymer
composition for treating clay or clay-bearing aggregates,
comprising: (A) a first component represented by the following
structure: ##STR00009## wherein R.sup.1, R.sup.2, and R.sup.3 each
independently represent hydrogen, C.sub.1-C.sub.3 alkyl, --COOH,
--CH.sub.2COOH, or mixtures thereof; X represents hydrogen or an
alkali metal; and (B) a second component represented by the
following structure: ##STR00010## wherein R.sup.4, R.sup.5,
R.sup.6, R.sup.7, and R.sup.8 each independently represent
hydrogen, C.sub.1-C.sub.3 alkyl, --COOH, or mixtures thereof; Y
represents --O--, --COO--, --OOC--, --COHN--, or --NHCO--; Z
represents (CH.sub.2).sub.n wherein "n" represents a whole number
of 0 to 6; and "m" represents an integer of 25 to 200; (C)
optionally a third component comprising a repeating unit of
polymerized (meth)acrylamide, N-alkyl (meth)acrylamide, N,N-dialkyl
(meth)acrylamide, 3-acrylamido-2-methylpropane sulfonic acid or its
salts, and styrene sulfonic acid or its salt, or mixtures thereof;
wherein the molar ratio of said first component A to said second
component B is in the range of 50:100 to 100:40 and the
weight-average molecular weight of the carboxylate graft polymer is
in the range of 22,000 to 250,000; and wherein, if the molar ratio
of said first component A to said second component B is greater
than 100:55, then the weight-average molecular weight of the
carboxylate graft polymer is in the range of 70,000 to 250,000.
16. The admixture composition of claim 15 further comprising at
least one repeating unit of polymerized (meth)acrylamide, N-alkyl
(meth)acrylamide, N,N-dialkyl (meth)acrylamide,
3-acrylamido-2-methylpropane sulfonic acid or its salts, and
styrene sulfonic acid or its salt, or mixtures thereof.
17. The admixture composition of claim 15 or 16 wherein said at
least one chemical admixture is a water reducer selected from the
group consisting of lignin sulfonate, naphthalene sulfonate
formaldehyde condensate, melamine sulfonate formaldehyde
condensate, polycarboxylate comb polymers containing alkylene oxide
groups, gluconates, and mixtures thereof.
18. A method for modifying clay-bearing aggregates, comprising:
introducing to a plurality of clay-bearing aggregates the
carboxylate graft polymer composition of claims 1 to 14.
19. A method for modifying cementitious materials containing
clay-bearing aggregates, comprising: introducing to a cementitious
binder and a plurality of clay-bearing aggregates the admixture
composition of claim 15, 16 or 17.
20. A method for modifying cementitious materials containing
clay-bearing aggregates, comprising: introducing to cementitious
binder and plurality of clay-bearing aggregates the carboxylate
graft polymer composition of claims 1 to 14.
21. A construction material, comprising: a plurality of aggregates,
clay, and the carboxylate graft polymer composition of claims 1 to
14.
Description
FIELD OF THE INVENTION
[0001] This invention relates to the treatment of clay-bearing
aggregates used for construction, and more particularly to the use
of a carboxylate graft polymer having high molecular weight and low
ratio of carboxylic acid to polyoxyalkylene groups.
BACKGROUND OF THE INVENTION
[0002] Concrete, mortar, asphalt, road base, well-drilling fluids
and muds, and other construction materials often contain clays that
are carried in the sand, rock, gravel, or other aggregates that are
used for making these construction materials or that are often
intermingled into these construction materials. Clays can adversely
affect the properties and/or performance of construction materials
because they absorb water and chemical agents used for treating
these materials.
[0003] A method for mitigating the deleterious effects of clays is
to wash the clay from the aggregates. However, excessive washing
can remove a portion of fines (i.e., small aggregates) that
otherwise benefits the performance or enhances a desired property
of the construction material.
[0004] An objective of the present invention is to mitigate the
deleterious effects of clays carried in aggregates while improving
one or more properties of the construction materials. The present
invention can lead to improvements in the properties of mortars and
concretes (e.g., workability, strength), asphalts (e.g., binder
demand), and road base materials (e.g., improved flowability).
Reducing or eliminating washing steps can lead to greater
beneficial fines content in construction materials.
[0005] Additional benefits can also be realized for clay
stabilization in gas and oil well applications (involving fractured
rock formations) to reduce water loss.
SUMMARY OF THE INVENTION
[0006] The present invention relates to clay-mitigating
compositions and methods for modifying clays that are carried (or
"born" or conveyed) or otherwise mixed within inorganic
particulates such as sand aggregates, crushed stone (gravel, rocks,
etc.), granulated slag, and other inorganic particles that are used
in construction applications and in construction materials.
[0007] The clay-mitigation agents of the present invention may be
incorporated into clay-bearing construction aggregates and
materials such as mortar, concrete, asphalt, road base, and well
bore drilling fluids and muds. The clay mitigation agents may be
introduced into dry or wet aggregates.
[0008] In the case of hydratable cementitious compositions, the
clay-mitigation methods and compositions of the present invention
can provide improved workability without increasing water demand of
cementitious binder systems. In the case of treating or washing
aggregate materials, the inventive compositions can reduce the
effort required for washing and/or removing of clay contained in
the aggregates.
[0009] As summarized above, an exemplary carboxylate graft polymer
composition of the present invention for treating clay or
clay-bearing aggregates comprises:
[0010] (A) a first component represented by the following
structure:
##STR00001##
wherein R.sup.1, R.sup.2, and R.sup.3 each independently represent
hydrogen, C.sub.1-C.sub.3 alkyl, --COOH, --CH.sub.2COOH, or
mixtures thereof; X represents hydrogen or an alkali metal; and
[0011] (B) a second component represented by the following
structure:
##STR00002##
wherein R.sup.4, R.sup.5, R.sup.6, R.sup.7, and R.sup.8 each
independently represent hydrogen, C.sub.1-C.sub.3 alkyl, --COOH, or
mixtures thereof; Y represents --O--, --COO--, --OOC--, --COHN--,
or --NHCO--; Z represents (CH.sub.2).sub.n wherein "n" represents a
whole number of 0 to 6; and "m" represents an integer of 25 to
200;
[0012] (C) optionally a third component comprising a repeating unit
of polymerized (meth)acrylamide, N-alkyl (meth)acrylamide,
N,N-dialkyl (meth)acrylamide, 3-acrylamido-2-methylpropane sulfonic
acid or its salts, and styrene sulfonic acid or its salt, or
mixtures thereof; and
[0013] wherein the molar ratio of said first component A to said
second component B is in the range of 50:100 to 100:40 and the
weight-average molecular weight of the carboxylate graft polymer is
in the range of 22,000 to 250,000; and
[0014] wherein, if the molar ratio of said first component A to
said second component B is greater than 100:55, then the
weight-average molecular weight of the carboxylate graft polymer is
in the range of 70,000 to 250,000.
[0015] Accordingly, the present invention also provides aggregate,
cementitious, and admixture compositions containing the described
carboxylate graft polymer composition. In other words, the
above-described carboxylate graft polymer can be combined with a
plurality of clay-bearing sand (natural or manufactured), crushed
rock or gravel, drilling mud, or other clay-bearing aggregates used
in construction to provide exemplary aggregate compositions of the
invention. As another example, the above-described carboxylate
graft polymer can be combined with a cementitious binder (e.g.,
Ordinary Portland Cement, argillaceous materials) to provide an
exemplary cementitious composition of the invention. As yet another
example, the above-described carboxylate graft polymer can be
combined with at least one chemical admixture selected from the
group consisting of water-reducing agent, set retarders, set
accelerators, air entraining agents, air detraining agents, and
mixtures thereof, to provide an exemplary admixture composition of
the invention.
[0016] The present invention thus also provides methods for
treating clay-bearing aggregates as well as construction materials
and cementitious compositions containing clay and aggregates.
Exemplary methods for treating clay or clay-bearing aggregates
comprises introducing the above-described carboxylate graft polymer
to clay or clay-bearing aggregates, or into construction materials
containing aggregates and clay (which may have been borne by the
aggregates).
[0017] Exemplary clay-mitigating carboxylate graft polymer
compositions of the invention may be introduced to clay-bearing
aggregates at the mine or quarry where aggregates are obtained
and/or manufactured. They may also be introduced at the concrete
mix plant wherein the aggregates are combined with cement to
provide mortar or concrete compositions. They may also be added at
any point before, during, or after these operations. The
clay-mitigation compositions may also be introduced into crushed
stone or rock which is contaminated with clay, such as crushed
gravel or rocks from quarries which are prepared for road base or
other construction use (e.g., foundations) and other construction
applications.
[0018] The above-described clay-mitigation compositions can also be
used, in other construction methods, such as in wellbore drilling
applications, such as servicing wellbores using a wellbore
servicing fluid, e.g., wellbore drilling (mud) fluid, mud
displacement fluid, and/or wellbore cementing composition, to
inhibit the swelling of argillaceous (shale or clay)
material-containing subterranean formation penetrated by the
wellbore.
[0019] The present invention thus relates to construction materials
which comprise a plurality of aggregates, clay, and the carboxylate
graft polymer described above.
[0020] Further advantages and benefits of the invention are
described in further detail hereinafter.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0021] The present invention relates to clay-mitigation
compositions and methods for treating clays contained in aggregates
such as sand, crushed rock, crushed gravel, drilling mud (or other
fluids pumped into well bore operations for recovering oil or gas),
and other clay-bearing aggregates which are used in or as part of
construction materials or operations.
[0022] In addition to clay-mitigation compositions containing the
carboxylate graft polymer as summarized previously, the present
invention also provides aggregate compositions (e.g., road base,
asphalts), cementitious compositions containing aggregates (e.g.,
mortars, concretes), and well-bore drilling muds or fluids (some of
which may or may not contain cementitious materials and/or
aggregates; and/or which are flowed through clay-bearing rock or
shale).
[0023] The present invention relates to treatment of all types of
clays. The clays may include but are not limited to swelling clays
of the 2:1 type (such as smectite type clays) or also of type 1:1
(such as kaolinite) or of the 2:1:1 type (such as chlorite). The
term "clays" has referred to aluminum and/or magnesium silicates,
including phyllosilicates having a lamellar structure; but the term
"clay" as used herein may also refer to clays not having such
structures, such as amorphous clays.
[0024] The present invention is also not limited to clays which
absorb polyoxyalkylene superplasticizers (such as ones containing
ethylene oxide ("EO") and/or propylene oxide ("PO") groups); but
also includes clays that directly affect the properties of
construction materials, whether in their wet or hardened state.
Clays which are commonly found in sands include, for example,
montmorillonite, illite, kaolinite, muscovite, and chlorite. These
are included in the methods and compositions of the present
invention.
[0025] Clay-bearing sands and/or crushed rock or gravel which are
treated by the method of the present invention may be used in
cementitious materials, whether hydratable or not, and such
cementitious materials include mortar, concrete, and asphalt, which
may be used in structural building and construction applications,
roadways, foundations, civil engineering applications, as well as
in precast and prefabrication applications.
[0026] The term "sand" as used herein shall mean and refer to
aggregate particles usually used for construction materials such as
concrete, mortar, and asphalt, and this typically involves granular
particles of average size between 0 and 8 mm (e.g., not including
zero), and, more preferably, between 2 and 6 mm. Sand aggregates
may comprise calciferous, siliceous or siliceous limestone
minerals. Such sands may be natural sand (e.g., derived from
glacial, alluvial, or marine deposits which are typically weathered
such that the particles have smooth surfaces) or may be of the
"manufactured" type, which are made using mechanical crushers or
grinding devices.
[0027] The term "cement" as used herein includes hydratable cement
and Portland cement which is produced by pulverizing clinker
consisting of hydraulic calcium silicates and one or more forms of
calcium sulfate (e.g., gypsum) as an interground additive.
Typically, Portland cement is blended with one or more supplemental
cementitious materials, such as fly ash, granulated blast furnace
slag, limestone, natural pozzolans, or mixtures thereof, and
provided as a blend. The term "cementitious" refers to materials
that comprise Portland cement or which otherwise function as a
binder to hold together fine aggregates (e.g., sand), coarse
aggregates (e.g., crushed stone, rock, gravel), or mixtures
thereof.
[0028] The term "hydratable" is intended to refer to cement or
cementitious materials that are hardened by chemical interaction
with water. Portland cement clinker is a partially fused mass
primarily composed of hydratable calcium silicates. The calcium
silicates are essentially a mixture of tricalcium silicate
(3CaO.SiO.sub.2 "C.sub.3S" in cement chemists notation) and
dicalcium silicate (2CaO.SiO.sub.2, "C.sub.2S") in which the former
is the dominant form, with lesser amounts of tricalcium aluminate
(3CaO.Al.sub.2O.sub.3, "C.sub.3A") and tetracalcium aluminoferrite
(4CaO.Al.sub.2O.sub.3.Fe.sub.2O.sub.3, "C.sub.4AF"). See e.g.,
Dodson, Vance H., Concrete Admixtures (Van Nostrand Reinhold, New
York N.Y. 1990), page 1.
[0029] The term "mortar" usually refers to a hydratable
cementitious mixture comprising a cementitious binder and a fine
aggregate that is typically sand, and water is added to initiate
hydration of the cement and hardening of the mixture. A "concrete"
comprises the cementitious binder, sand, and further comprises a
coarse aggregate such as crushed stone, rock, or gravel. Both
mortars and concrete may additionally contain one or more chemical
admixtures. As clays may be contained in the sand used for making
the mortar or concrete, such mortars and concretes may in a sense
to describe as both clay-bearing aggregate compositions as well as
hydratable cementitious compositions which contain aggregates and
clay.
[0030] As summarized previously, an exemplary carboxylate graft
polymer composition of the present invention for treating clay or
clay-bearing aggregates comprises:
[0031] (A) a first component represented by the following
structure:
##STR00003##
wherein R.sup.1, R.sup.2, and R.sup.3 each independently represent
hydrogen, C.sub.1-C.sub.3 alkyl, --COOH, --CH.sub.2COOH, or
mixtures thereof; X represents hydrogen or an alkali metal; and
[0032] (B) a second component represented by the following
structure:
##STR00004##
wherein R.sup.4, R.sup.5, R.sup.6, R.sup.7, and R.sup.8 each
independently represent hydrogen, C.sub.1-C.sub.3 alkyl, --COOH, or
mixtures thereof; Y represents --O--, --COO--, --OOC--, --COHN--,
or --NHCO--; Z represents (CH.sub.2).sub.n wherein "n" represents a
whole number of 0 to 6; and "m" represents an integer of 25 to
200;
[0033] (C) optionally a third component comprising a repeating unit
of polymerized (meth)acrylamide, N-alkyl (meth)acrylamide,
N,N-dialkyl (meth)acrylamide, 3-acrylamido-2-methylpropane sulfonic
acid or its salts, and styrene sulfonic acid or its salt, or
mixtures thereof; and
[0034] wherein the molar ratio of said first component A to said
second component B is in the range of 50:100 to 100:40 and the
weight-average molecular weight of the carboxylate graft polymer is
in the range of 22,000 to 250,000; and
[0035] wherein, if the molar ratio of said first component A to
said second component B is greater than 100:55, then the
weight-average molecular weight of the carboxylate graft polymer is
in the range of 70,000 to 250,000.
[0036] In preferred embodiments, the above-described carboxylate
graft polymer composition further comprises at least one repeating
unit of the identified component "C" compounds selected from
repeating unit of polymerized (meth)acrylamide, N-alkyl
(meth)acrylamide, N,N-dialkyl (meth)acrylamide,
3-acrylamido-2-methylpropane sulfonic acid or its salts, and
styrene sulfonic acid or its salt, or mixtures thereof.
[0037] In preferred carboxylate graft polymer compositions, the
molar ratio of component A to component B is between 0.6 and 1.8,
and more preferably between 0.7 and 1.5; and the weight-average
molecular weight of said carboxylate graft polymer composition is
preferably in the range of 70,000 to 150,000. The number-average
molecular weight of said component B is in the range of 1,000 to
10,000; preferably in the range of 2,000 to 5,000 and most
preferably, it is in the range of 1,500 to 7,500.
[0038] The carboxylate graft polymer of the invention can be formed
either by direct polymerization of a carboxylate monomer of
component A with a polyoxyalkylene macromonomer of component B,
optionally with an unsatured monomer of component C; or by grafting
of polyoxyalkylene groups onto a carboxylic polymer.
[0039] Carboxylate monomers of component A can be selected, for
example, from a list including acrylic acid, methacrylic acid,
crotonic acid, maleic acid, fumaric acid, itaconic acid, anhydride
or salt of these acids, or mixtures thereof.
[0040] Examples of polyoxyalkylene macromonomer of component B
include, without limitation, polyoxyalkylene acrylate ester,
polyoxyalkylene methacrylate ester, polyoxyalkylene maleate ester,
polyoxyalkylene fumarate ester, polyoxyalkylated C.sub.2 to C.sub.7
unsaturated alcohol, N-polyoxyalkylene acrylamide,
N-polyoxyalkylene methacrylamide, or mixtures thereof.
[0041] Examples of unsatured monomer of component C include,
without limitation, acrylamide, methacrylamide, N-alkyl acrylamide,
N-alkyl methacrylamide, N,N-dialkyl acrylamide, N,N-dialkyl
methacrylamide, vinylsulfonic acid, allylsulfonic acid,
methallylsulfonic acid, 3-acrylamido-2-methylpropane sulfonic acid,
styrene sulfonic acid, salts of these acids, or mixtures
thereof.
[0042] Alternatively, the carboxylate graft polymer of the
invention can be prepared by grafting of the polyoxyalkylene groups
onto a carboxylic acid or anhydride polymer. The carboxylic polymer
includes homo- or copolymer of acrylic acid, methacrylic acid,
crotonic acid, maleic acid, fumaric acid, itaconic acid, anhydride
or salt of these acids, or mixtures thereof. The chemical linkage
of the polyoxyalkylene and the carboxylic polymer can be an ester,
amide, imide, or mixtures thereof.
[0043] In preferred methods and compositions of the invention,
carboxylate graft polymers of the present invention have little or
no water reducing ability when used in hydratable cementitious
compositions such as concrete, mortar, and cements. In other words,
carboxylate graft polymers of the invention should not be
superplasticizers, and most preferably they should not have the
ability to confer significant slump increase either initially or
over time. Any increase slump in plastic hydratable cementitious
compositions such as cement, mortar, or concrete should be 0-4
inches (using standard inverted slump cone measurement); more
preferably, less than 3 inches; and, most preferably, less than 2
inches, at normal dosage range (i.e., 0.08 to 0.15% dry polymer
weight to dry cement weight), as compared to a control concrete mix
that does not contain a water-reducing admixture. In addition, it
is preferred that the slump of plastic concrete containing the
carboxylate graft polymers of the invention does not exhibit an
increase in slump over time. Hence, exemplary clay-mitigating
compositions, cementitious compositions, and aggregate compositions
of the invention contain the carboxylate graft polymer which
increases slump 0-4 inches, more preferably 0-3 inches, and most
preferably 0-2 inches (using slump cone standard, e.g., ASTM C143
(which the inventors believed was last updated in 2010 but which
has used the same cone for many years).
[0044] Exemplary aggregate compositions of the present invention
comprise a plurality of clay-bearing aggregates and the
above-described carboxylate graft polymer composition. The
aggregates may comprise, for example, clay-bearing aggregates
including natural or manufactured sand, crushed stone, crushed
gravel, crushed rock, crushed shale, or mixtures thereof. Such
aggregate compositions may further comprise a cementitious
binder.
[0045] The carboxylate graft polymer can be used in the plurality
of clay-bearing aggregates in an amount of 0.1% to 100% by weight
based on dry weight of clay contained in the plurality of
aggregates, and more preferably in an amount of 1% to 50% by weight
based on dry weight of clay contained in said plurality of
aggregates.
[0046] Exemplary admixture compositions of the present invention
comprise the above described clay-mitigating carboxylate graft
polymer and one or more conventional chemical admixtures. The
admixtures include, without limitation, water reducing agents (such
as lignin sulfonate, naphthalene sulfonate formaldehyde condensate
(NSFC), melamine sulfonate formaldehyde condensate (MSFC),
polycarboxylate comb polymers (containing alkylene oxide groups
such as ethylene oxide ("EO") and/or propylene oxide ("PO")
groups), gluconic acid and/or gluconate, and the like); set
retarders; set accelerators; defoamers; air entraining agents;
surface active agents; and mixtures thereof.
[0047] Admixtures that include EO-PO type polymers, e.g., which
have EO and/or PO groups, and polycarboxylic acid and/or salt
groups, are preferred.
[0048] Exemplary cement dispersants (admixtures) contemplated for
use in methods and compositions of the invention include EO-PO
polymers and EO-PO comb polymers, as described for example in U.S.
Pat. Nos. 6,352,952 B1 and 6,670,415 B2 of Jardine et al., which
mentioned the polymers taught in U.S. Pat. No. 5,393,343 (assigned
to W. R. Grace & Co.-Conn.). Another exemplary cement
dispersant polymer, also containing EO/PO groups, is obtained by
polymerization of maleic anhydride and an
ethylenically-polymerizable polyalkylene, as taught in U.S. Pat.
No. 4,471,100. In addition, EO/PO-group-containing cement
dispersant polymers are taught in U.S. Pat. No. 5,661,206 and U.S.
Pat. No. 6,569,234. The amount of such polycarboxylate cement
dispersants used within concrete may be in accordance with
conventional use (e.g., 0.05% to 0.25% based on weight of active
polymer to weight of cementitious material).
[0049] The dosage of dispersant admixtures and any other admixtures
within the compositions of the invention will depend on
application, nature and quality of the cement, water/cement ratio,
temperature, application objectives, other admixtures employed, and
other factors typically considered by the construction
worker/artisan.
[0050] Suitable water-reducing admixtures, suitable for use with
the carboxylate graft polymers of the present invention, are
available from Grace Construction Products, Cambridge, Mass., under
the trade name "ADVA."
[0051] Thus, an exemplary admixture composition for modifying a
cementitious composition comprises:
[0052] (i) at least one chemical admixture selected from the group
consisting of water-reducing agent, set retarders, set
accelerators, air entraining agents, air detraining agents, and
mixtures thereof; and
[0053] (ii) a carboxylate graft polymer composition for treating
clay or clay-bearing aggregates, comprising: [0054] (A) a first
component represented by the following structure:
[0054] ##STR00005## [0055] wherein R.sup.1, R.sup.2, and R.sup.3
each independently represent hydrogen, C.sub.1-C.sub.3 alkyl,
--COOH, --CH.sub.2COOH, or mixtures thereof; X represents hydrogen
or an alkali metal; and [0056] (B) a second component represented
by the following structure:
[0056] ##STR00006## [0057] wherein R.sup.4, R.sup.5, R.sup.6,
R.sup.7, and R.sup.8 each independently represent hydrogen,
C.sub.1-C.sub.3 alkyl, --COOH, or mixtures thereof; Y represents
--O--, --COO--, --OOC--, --COHN--, or --NHCO--; Z represents
(CH.sub.2).sub.n wherein "n" represents a whole number of 0 to 6;
and "m" represents an integer of 25 to 200; [0058] (C) optionally a
third component comprising a repeating unit of polymerized
(meth)acrylamide, N-alkyl (meth)acrylamide, N,N-dialkyl
(meth)acrylamide, 3-acrylamido-2-methylpropane sulfonic acid or its
salts, and styrene sulfonic acid or its salt, or mixtures thereof;
[0059] wherein the molar ratio of said first component A to said
second component B is in the range of 50:100 to 100:40 and the
weight-average molecular weight of the carboxylate graft polymer is
in the range of 22,000 to 250,000; and [0060] wherein, if the molar
ratio of said first component A to said second component B is
greater than 100:55, then the weight-average molecular weight of
the carboxylate graft polymer is in the range of 70,000 to
250,000.
[0061] An exemplary method of the present invention for treating
clay or clay-bearing aggregates comprises introducing to clay or to
clay-bearing aggregates (such as mortar or concrete aggregates,
asphalt aggregates, road base aggregates) in an amount of 0.1% to
100% by weight based on dry weight of the clay being treated, the
carboxylate graft polymer as described above.
[0062] The carboxylate graft polymer also preferably has a
weight-average molecular weight of 22,000 to 250,000, and more
preferably more than 70,000, as measured by aqueous gel permeation
chromatography (GPC) using poly(ethylene glycol) as calibration
standard. A Waters 1500 series system equipped with three columns
and a refractive index detector was employed. GPC columns are
commercially available from Waters Corporation, under the trade
names ULTRAHYDROGEL.TM. 120, ULTRAHYDROGEL.TM. 250 and
ULTRAHYDROGEL.TM. 500. The GPC processing conditions are as
follows: 0.1M aqueous potassium nitrate as elution solvent, flow
rate of 0.8 mL/min, injection volume of 10 .mu.L, and column
temperature at 30.degree. C.
[0063] In further exemplary embodiments, carboxylate graft polymers
are introduced to clay contained in aggregates (e.g., mortar or
concrete aggregates, asphalt aggregates, road base aggregates), in
the amount of 0.1% to 100% (as previously mentioned), more
preferably in an amount of 1% to 50%, and most preferably in an
amount of 2% to 25% by weight based on dry weight of the clay
contained in said aggregates.
[0064] It is understood that the foregoing description of an
aggregate composition applies to a clay-bearing plurality of
aggregates which may be in a dry pile state (e.g., located in
supply piles at the mine or quarry or concrete plant, located at a
preparation site for installation as road base, etc.) or may be
within a wet cementitious slurry (e.g., concrete, mortar). With
respect to dry aggregate compositions of the present invention
containing the carboxylate graft polymer (which is deposited upon
or mixed into the aggregates), an exemplary method of the present
invention for modifying cementitious compositions comprises
combining the dry aggregate containing the carboxylate graft
polymer with a cementitious binder.
[0065] In further exemplary embodiments, the admixture compositions
comprise at least one chemical admixture selected from the group of
oxyalkylene-containing water-reducing admixture, shrinkage reducing
admixture, or mixture thereof, in combination with said carboxylate
graft polymer. Exemplary methods of the invention comprise
combining said admixture compositions with a hydratable
cementitious binder, either before, during, or after combining said
cementitious binder with clay-bearing aggregates to create a mortar
or concrete material.
[0066] For construction materials generally, the carboxylate graft
polymers of the present invention may be introduced to aggregates
(e.g., sand) by application to the clay-bearing aggregates at the
quarry or mine; by application at the concrete mix plant where the
aggregates are combined with cement to form hydratable mortar or
concrete; or by application at an asphalt plant wherein
clay-bearing aggregates are combined with bituminous binder. The
carboxylate graft polymers of the present invention may also be
incorporated into the aggregates at the concrete mix plant before
the cement binder is added or into dry or wet mortar or concrete
containing the aggregates. Additionally, the polymer may be used
together with conventional concrete admixtures such as water
reducers (such as superplasticizers), set retarders, set
accelerators, air detraining agents, air entraining agent,
shrinkage reducing agents, crack control agents, strength enhancing
agents, fibers, and the like.
[0067] Concerning gas and oil well applications, the functionalized
water-soluble polyamines of the present invention may be introduced
into the aqueous well bore cement slurry or drilling fluid or mud,
which in turn stabilizes subterranean clay-bearing formations.
[0068] As mentioned in the summary, the above-described carboxylate
graft polymer can also be used in wellbore drilling applications,
such as wellbore mud drilling fluid and/or wellbore cementing
compositions and methods for servicing wellbores. Natural resources
such as gas, oil, and water residing in subterranean formations or
zones are usually recovered by drilling a wellbore down to the
subterranean formation while circulating a drilling fluid (also
known as a drilling mud) through the drill pipe and the drill bit
and upwardly through the wellbore to the surface. The drilling
fluid serves to lubricate the drill bit and carry drill cuttings
back to the surface. After the wellbore is drilled to the desired
depth, the drill pipe and drill bit are typically withdrawn from
the wellbore while the drilling fluid is left in the wellbore while
the drilling fluid is left in the wellbore to provide hydrostatic
pressure on the formation penetrated by the wellbore and thereby
prevent formation fluids from flowing into the wellbore. Next, the
wellbore drilling operation involves running a string of pipe,
e.g., casing, in the wellbore. Primary cementing is then typically
performed whereby a cement slurry is pumped down through the string
of pipe and into the annulus between the string of pipe and the
walls of the wellbore, whereby the drilling mud is displaced, and
the cement slurry sets into a hardened mass (i.e., sheath) and
thereby seals the annulus.
[0069] The present inventors believe that the above-described
carboxylate graft polymer is suitable for use as a clay mitigating
agent in aqueous wellbore drilling fluid (mud) compositions and/or
wellbore cementing compositions. Among the advantages or purposes
of doing this is to stabilize argillaceous formations like shales
and/or clays in the wellbore which could otherwise be weakened and
displaced by water in the aqueous wellbore mud. Because of the
saturation and low permeability of a shale formation, penetration
of a small volume of wellbore fluid into the formation can result
in a considerable increase in pore fluid pressure near the wellbore
wall, which, in turn, can reduce the effective cement support,
which leads to a less stable wellbore condition.
[0070] Thus, the present invention also concerns a method for
servicing a wellbore comprising: introducing to a wellbore
formation an aqueous wellbore servicing fluid (e.g., drilling mud,
spacer fluid, mud displacement fluid, cementing composition, or
combination thereof) comprising the above-described carboxylate
graft polymer.
[0071] In addition to the carboxylate graft polymer, the exemplary
drilling mud or cementing composition can further contain
conventional cementitious compositions, surfactants, or
combinations thereof. For example, the cementitious composition may
comprise a cement such as a hydraulic cement (as previously defined
above), and this cement may include calcium, aluminum, silicon,
oxygen, and/or sulfur and which sets and hardens by reaction with
water. Examples of hydraulic cements include but are not limited to
Portland cements (e.g., classes A, C, G, and H Portland cements),
pozzolan cements, high alumina cements, silica cements, high
alkalinity cements, and combinations thereof.
[0072] While the invention is described herein using a limited
number of embodiments, these specific embodiments are not intended
to limit the scope of the invention as otherwise described and
claimed herein. Modification and variations from the described
embodiments exist. More specifically, the following examples are
given as a specific illustration of embodiments of the claimed
invention. It should be understood that the invention is not
limited to the specific details set forth in the examples.
[0073] All parts and percentages in the examples, as may be set
forth herein and hereinafter, are by percentage dry weight unless
otherwise specified.
Example 1
[0074] Into a reaction vessel equipped with a thermometer, stirrer,
nitrogen inlet tube, reflux condenser and two dropping devices,
164.41 g of distilled water was charged. The reaction vessel was
purged with nitrogen and heated to 86.degree. C. Two separate
solutions were prepared. Solution A contained 105.5 g of distilled
water, 2.65 g of ammonium persulfate and 8.84 g of 35% hydrogen
peroxide. Solution B contained 428.42 g of aqueous polyoxyethylene
methyl ether methacrylate (Mw=3,068, 60.9% solution), 5.29 g of
methacrylic acid, 7.96 g of acrylic acid and 1.77 g of
3-mercaptopropionic acid.
[0075] While reaction vessel temperature was maintained around
86.degree. C., both solution A and solution B were added drop-wise
over periods of 3.5 hours and 3.0 hours, respectively. After the
addition, the reaction was continued for 2 hours at 86.degree. C.;
then the mixture was cooled. To neutralize the mixture, 6.7 g of
50% aqueous sodium hydroxide solution was added at 70.degree. C.
The resulting material is designated as P-9.
[0076] Aqueous Gel Permeation Chromatography (GPC) measurement of
the resulting carboxylate graft polymer indicated a weight-average
molecular weight of 139,000 for the polymer peak using polyethylene
glycol (PEG) as standard for calibration. The GPC columns used were
obtained from Waters Corporation, Massachusetts, USA, and had the
trade names ULTRAHYDROGEL.TM. 120, ULTRAHYDROGEL.TM. 250 and
ULTRAHYDROGEL.TM. 500. The GPC processing conditions were as
follows: 0.1M aqueous potassium nitrate as elution solvent, flow
rate of 0.8 mL/min, injection volume of 10 .mu.L, column
temperature at 30.degree. C., and refractive index detection for a
Waters 1500 series system.
[0077] Using the above procedures, carboxylate polymer samples were
synthesized, designated as "P-#", and characteristics were
summarized, along with commercial polymers (reference) designated
as "R-#", in Table 1 below.
TABLE-US-00001 TABLE 1 A/B Molecular weight Polymer peak
Description molar ratio of component B [Mw, k] P-1 1.2 3000 139 P-2
2.0 2000 21 P-3 1.5 2000 20 P-4 2.0 5000 19 P-5 1.5 5000 20 P-6 2.0
2000 54 P-7 1.5 2000 44 P-8 1.2 3000 47 P-9 2.0 5000 79 P-10 1.5
2000 10 P-11 1.5 5000 15 P-12 1.3 3000 49 P-13 1.5 5000 69 P-14 1.5
5000 83 P-15 1.5 5000 104 P-16 1.5 5000 143 R-1 4.3 2000 37 R-2 2.3
2000 38
Example 2
[0078] To demonstrate the ability of carboxylate graft polymers of
the present invention to minimize increases in slump,
non-clay-bearing sand was used to make concrete samples. The
concrete samples included a control which contained no carboxylate
graft polymer, a commercial polycarboxylate polymer (prior art used
as a reference), and a synthesized carboxylate graft polymer of the
present invention. Synthesized carboxylate graft polymers in this
example were in the lower range of main peak molecular weights for
commercially available polycarboxylate polymers.
[0079] The concrete mix design included the following components:
Cement--391 kg/m.sup.3 with an alkali equivalent of 0.49% and a
free calcium oxide content of 1.39%; Sand--800 kg/m.sup.3;
Stone--1068 kg/m.sup.3; Water--157 kg/m.sup.3 for a water-to-cement
ratio of 0.40. The dosage for the polymers (either the carboxylate
graft polymer of the invention or commercially available
polycarboxylate polymer) was 0.11% actives/cement wt. Each concrete
mix was treated with air detraining agent.
[0080] The mixing procedure was as follows: (1) mix sand, stone,
and water for one minute; (2) add cement and mix for two minutes;
(3) add polymer and mix for two minutes; (4) stop mixer and rest
for three minutes; and (5) re-mix for 2 minutes. After mixing, the
slump, air content and the 1-, 7-, and 28-day compressive strength
of the concrete samples were measured. Results are shown in Table
2.
TABLE-US-00002 TABLE 2 Slump Air Compressive strength (MPa) at
Polymer (mm) (%) 1 day 7 days 28 days Blank 10 2.7 24 35 41 R-1 220
1.6 26 39 48 R-2 250 1.5 27 44 49 P-2 200 3.0 26 43 48 P-3 60 3.7
21 39 46 P-4 40 3.2 20 35 42 P-5 10 3.3 21 38 44
[0081] To minimize increases in slump, the present inventors
discovered that the A/B molar ratio must be decreased below 2.0
(P-2 compared to P-3) or the molecular weight of component B must
be increased above 2000 (P-2 compared to P-4). The present
inventors discovered that the carboxylate graft polymer with the
lowest A/B molar ratio and greatest molecular weight of component B
exhibited the lowest slump (P-5).
Example 3
[0082] To demonstrate further the ability of the carboxylate graft
polymer to minimize increases in slump, the present inventors
conducted a second set of experiments using the same mix design and
protocol of Example 2. In this example, the synthesized carboxylate
graft polymers were either in the high range of main peak molecular
weights for commercially available polycarboxylates or higher. The
results are shown in Table 3.
TABLE-US-00003 TABLE 3 Slump Air Compressive strength (MPa) at
Polymer (mm) (%) 1 day 7 days 28 days Blank 10 2.7 24 35 41 R-1 220
1.6 26 39 48 R-2 250 1.5 27 44 49 P-6 230 1.7 24 43 49 P-7 220 3.5
26 36 50 P-8 90 2.5 24 41 47 P-9 40 2.7 21 37 45 P-l 30 3.0 20 35
41
[0083] In this example, to obtain least slump increase in the
concrete mix, the present inventors discovered that the A/B molar
ratio must be decreased below 2.0 (P-6 and P-7 compared to P-8) or
the molecular weight of component B must be increased above 2000
(P-6 compared to P-9). Increasing the main peak molecular weight
was also seen to minimize slump (P-9 compared to P-1).
Example 4
[0084] To demonstrate the ability of carboxylate graft polymers of
the present invention to function as clay mitigation agents, the
present inventors tested concrete using sand doped with clay and
compared performance against known clay-mitigating agent involving
the polycondensates of epichlorohydrin and dimethylamine
(hereinafter "EPI-DMA"). The carboxylate graft polymers used as
potential clay mitigating agents were chosen to have low ability in
increasing slump and a range of main peak molecular weights.
[0085] The concrete mix design included the following components:
Cement--445 kg/m.sup.3 with an alkali equivalent of 0.49% and a
free calcium oxide content of 1.39%; Sand--884 kg/m.sup.3;
Clay--sodium montmorillinite, 1.15 g/m.sup.3 (0.13% solids/sand);
Stone--886 kg/m.sup.3; Water--184 kg/m.sup.3 for a water-to-cement
ratio of 0.41; Polycarboxylate superplasticizer formulated with a
defoamer--0.145 wt % solids/cement. The dosage for the clay
mitigation agents was 10% solids/clay.
[0086] The mixing procedure was as follows: (1) mix sand, clay, 1/3
of mixing water and clay mitigating agent together for five
minutes; (2) add stone and mix for one minute; (3) add cement and
mix for two minutes; (4) add polymer and mix for two minutes; (5)
stop mixer and rest for three minutes; (6) re-mix for 2 minutes.
After mixing, the slump flow (diameter of the spread), air content
and the 1-, 7-, and 28-day compressive strength of the concrete
were determined. The results are shown in Table 4.
TABLE-US-00004 TABLE 4 Slump Air Compressive strength (MPa) at Clay
mitigating agent (mm) (%) 1 day 7 days 28 days EPI-DMA 640 1.9 25
38 51 P-10 480 2.8 26 41 48 P-11 560 2.4 26 38 48 P-3 580 2.4 26 37
49 P-2 630 2.1 27 41 47 P-12 650 2.1 25 42 46 P-13 670 2.0 26 40 48
P-14 650 2.1 25 39 47 P-15 650 2.0 25 42 49 P-16 690 1.8 26 40
49
The higher the main peak molecular weight, the more effective the
carboxylate graft polymer was in mitigating clay. At a main peak
molecular weight of around 50,000, the performance of known clay
mitigating agent EPI-DMA was exceeded.
Example 5
[0087] To demonstrate clay-mitigating ability of carboxylate graft
polymer to minimize increase in slump flow, the present inventors
tested concrete using the mix design and protocol of Example 4. Two
polymers were compared: P-6, a typical water-reducing
polycarboxylate; and P-1, the carboxylate graft polymer. Dosages of
each were increased from 10 to 40% solids/clay; and segregation of
the mix was checked visually. Results are summarized in Table
5.
TABLE-US-00005 TABLE 5 Slump flow(mm) Air (%) Dose [% s/clay] P-6
P-1 P-6 P-1 0, with clay 480 2.5 10 620 650 1.8 1.8 20 700 670 1.5
1.6 30 720* 710 0.9 1.5 40 740* 710 1.8 1.5 0, without clay 710 1.4
*indicates a visibly segregated mix
Both polymers mitigated the clay effect. A 10% dose, P-1 was more
effective than P-6. However, as dosage increased, due to dispersing
effect of P-6, slump flow continued to increase beyond that of
concrete without clay. This uncontrolled increase in workability
translated to visible segregation of the concrete. P-1, however,
with only clay-mitigating properties, restored workability and
provided no additional dispersion.
[0088] The foregoing examples and embodiments were presented for
illustrative purposes only and not intended to limit the scope of
the invention.
* * * * *