Hydrophobic, cationic polymers for treating construction aggregates

Abstract

The present invention provides methods, admixture compositions for treating clay-bearing aggregates used for construction purposes, and aggregate compositions for construction purposes. The clay-bearing aggregates are treated with a cationic copolymer made from two and preferably three different monomer components. Cementitious compositions containing the treated aggregates are also described.

Claims

1. A composition comprising: (i) a water-reducer for modifying hydratable mortar or concrete; and (ii) at least one copolymer obtained from monomer components as follows: (A) a cationic monomer represented by one of the following structures ##STR00003## wherein R.sub.1, R.sub.2, and R.sub.3 each independently represent hydrogen, —CH.sub.3, or —COOH; R.sub.4, R.sub.5, R.sub.6, R.sub.7, and R.sub.8 each independently represent a C.sub.1-C.sub.4 alkyl group; R.sub.9 and R.sub.10 each independently represent hydrogen or —CH.sub.3; Z.sub.1 represents —O— or —NH—; Y.sub.1 represents —CH.sub.2CH(OH)CH.sub.2— or C.sub.1-C.sub.6 alkyl group; and X represents a halide, pseudohalide, or sulfate; and (B) a hydrophobic, essentially water-insoluble monomer selected from the group consisting of vinyl acetate, acrylonitrile, styrene and its derivatives, vinyl ether of formula CH.sub.2═CH—O—R.sub.11 in which R.sub.11 is a group selected from a linear or branched, saturated or unsaturated, hydrocarbon radical moiety having from 1 to 6 carbons, and ester or amide represented by the formula H.sub.2C═CR.sub.12—CO—Z.sub.2—R.sub.13 in which R.sub.12 is a hydrogen or C.sub.1 to C.sub.3 alkyl group, Z.sub.2 is —O— or —NH—, and R.sub.13 is a linear or branched, saturated or unsaturated hydrocarbon radical moiety having from 1 to 8 carbons; wherein said water reducer is selected from the group consisting of lignin sulfonate, naphthalene sulfonate formaldehyde condensate (NSFC), melamine sulfonate formaldehyde condensate (MSFC), and mixture thereof.

2. The composition of claim 1 wherein said copolymer has a molecular weight of 1,000-100,000.

3. The composition of claim 1, wherein said copolymer has a molecular weight of 2,000-60,000.

4. The composition of claim 1, wherein said copolymer has a molecular weight of 5,000-50,000.

5. The composition of claim 1 wherein the molar ratio (A:B) of said first monomer component (A) to said second monomer component (B) is 0.75:0.25 to 0.98:0.02.

6. The composition of claim 1 wherein the molar ratio (A:B) of said first monomer component (A) to said second monomer component (B) is 0.80:0.20 to 0.95:0.05.

7. The composition of claim 1 wherein each of R.sub.7 and R.sub.8 are —CH.sub.3 groups, and each of R.sub.9 and R.sub.10 are hydrogen.

8. The composition of claim 1 wherein Z.sub.1 is oxygen and Y.sub.1 is —CH.sub.2CH.sub.2—.

9. The composition of claim 1 wherein Z.sub.1 is —NH— and Y.sub.1 is —CH.sub.2CH.sub.2CH.sub.2—.

10. The composition of claim 1 wherein said copolymer has two or more monomer components which are represented by said structures of said monomer component (A).

11. The composition of claim 1 wherein said copolymer has two or more monomer components which are represented by said structures of said monomer component (B).

12. The composition of claim 1 wherein said copolymer further comprises a monomer selected from the group consisting of acrylamide, methacrylamide, alkyl acrylamide, dialkyl acrylamide, alkyl methacrylamide, dialkyl methacrylamide, polyalkyleneoxide acrylate, polyalkyleneoxide methacrylate, and polyalkyleneoxide ether.

13. The composition of claim 1 further comprising gluconate, EO/PO polymer, or mixture thereof.

14. The composition of claim 1 further comprising a cement binder.

15. The composition of claim 1 further comprising aggregates.

16. The composition of claim 14 further comprising aggregates.

17. The composition of claim 1 further comprising an admixture chosen from set retarders, set accelerators, defoamers, air entraining agents, surface active agents, or mixtures thereof.

18. A concrete composition comprising the composition of claim 1.

19. An aggregate composition comprising the composition of claim 1.

20. The aggregate composition of 19 further comprising a gluconate and EO/PO polymer.

Description

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

(1) The present invention pertains to method and compositions for treating clays in sand aggregates intended for construction material purposes using a hydrophobically-modified cationic polymer, as well as to cement and cementitious compositions, aggregate compositions, and concrete compositions containing the hydrophobically-modified cationic polymer.

(2) The clays may be 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 this term may also refer to clays not having such structures, such as amorphous clays. The present invention is not limited to swelling clays, which have been seen to absorb EO/PO superplasticizers as previously mentioned in the background, but also includes the use of clays that may 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 also included in the methods and compositions of the invention.

(3) The clay-bearing sands 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 concrete, mortar, 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.

(4) 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, 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 made using mechanical crushers or grinding devices.

(5) The construction materials in which the sand is used include hydratable cementitious compositions, such as mortar and concrete, and also may involve asphalt compositions.

(6) 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 combined with one or more supplemental cementitious materials, such as Portland cement, 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 gravel), or mixtures thereof.

(7) 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.

(8) The term “concrete” will be used herein generally to refer to a hydratable cementitious mixture comprising water, cement, sand, usually a coarse aggregate such as crushed gravel, and optional chemical admixture(s).

(9) As used herein, the term “copolymer” or “polymer” as used herein refers to compounds containing at least two different monomer components (designated as “A” and “B”) and optionally at least three different monomer components (further including optional monomer designated as “C”).

(10) The copolymers of the invention are preferably made by conventional addition polymerization techniques such as radical polymerization. Preferably, the polymerization is conducted in aqueous solution using a water soluble free radical initiator including peroxides, such as hydrogen peroxide; persulfates, such as ammonium, sodium, or potassium persulfate; and water soluble azo initiators. Preferably, the molecular weight range of the copolymer is 1000-100,000; more preferably 2,000-60,000; and most preferably the molecular weight range is 5,000-50,000.

(11) As summarized above, exemplary methods of the present invention involve introducing the copolymer to clay-bearing aggregates at a quarry or mining plant, where the aggregate is manufactured or washed, or the copolymer can be introduced to the clay-bearing aggregates at a concrete mixing plant, where cement and aggregates are combined to make a hydratable mortar or concrete. In further exemplary methods, the copolymer can also be added directly into the mortar or concrete, separately or together or in mixture with one or more conventional admixtures. Such conventional admixtures may include for example, lignin sulfonate, naphthalene sulfonate formaldehyde condensate (NSFC), melamine sulfonate formaldehyde condensate (MSFC), polycarboxylate comb polymers, gluconate, set retarders, set accelerators, defoamers, air entraining agents, surface active agents, or mixtures thereof.

(12) Of the admixtures, so-called EO/PO type polymers, which have ethylene oxide (“EO”) and/or propylene oxide (“PO”) groups and polycarboxylate groups, are preferred. Cement dispersants contemplated for use in 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. These polymers are available from Grace under the trade name “ADVA®”. 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. 6,569,234 B2 and U.S. Pat. No. 5,661,206. 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).

(13) Thus, exemplary admixture compositions of the invention comprise: the above-described copolymer and at least one polycarboxylate cement dispersant, which is preferably a polycarboxylate comb polymer having EO and PO groups, as described above.

(14) As summarized above, an exemplary method of the present invention comprises: introducing to clay-bearing sand aggregates, in an amount of 3% to 60% based on weight of clay treated, at least one copolymer obtained from monomer components (A), (B), and optionally (C), as follows:

(15) (A) in an amount of 60-98 mol percent, a cationic polymer selected from quaternized vinyl pyridine or other cationic monomer represented by the following structures

(16) ##STR00002##
wherein

(17) R.sub.1, R.sub.2, and R.sub.3 each independently represent hydrogen, —CH.sub.3, or —COOH;

(18) R.sub.4, R.sub.5, R.sub.6, R.sub.7, and R.sub.8 each independently represent a C.sub.1-C.sub.4 alkyl group;

(19) R.sub.9 and R.sub.10 each independently represent hydrogen or —CH.sub.3;

(20) Z.sub.1 represents —O— or —NH—;

(21) Y.sub.1 represents —CH.sub.2CH(OH)CH.sub.2— or C.sub.1-C.sub.6 alkyl group; and

(22) X represents a halide, pseudohalide, or sulfate;

(23) (B) in an amount of 2-40 mol percent, a hydrophobic, essentially water-insoluble monomer selected from the group consisting of vinyl acetate, acrylonitrile, methacrylonitrile, styrene and its derivatives, vinyl ethers of formula CH.sub.2═CH—O—R.sub.11 in which R.sub.11 is a linear or branched, saturated or unsaturated hydrocarbon radical from 1 to 12 carbons, esters or amides of formula H.sub.2C═CR.sub.12—CO—Z.sub.2—R.sub.13 in which R.sub.12 is hydrogen or C.sub.1 to C.sub.3 alkyl, Z.sub.2 is —O— or —NH—, and R.sub.13 is a linear or branched, saturated or unsaturated hydrocarbon radicals having from 1 to 18 carbons; and

(24) (C) in an amount of 0-20 mol percent, a water-soluble monomer selected from the group consisting of acrylamide, methacrylamide, alkyl or dialkyl acrylamide of methacrylamide, polyalkyleneoxide acrylate, polyalkyleneoxide methacrylate, and polyalkyleneoxide ether.

(25) Monomer component (A) can be chosen, for example, from a list including diallyl dimethyl ammonium chloride (DADMAC), 2-acryloyloxyethyl trimethyl ammonium chloride (AETAC), 2-methacryloyloxyethyl trimethyl ammonium chloride (METAC), acrylamidopropyl trimethyl ammonium chloride (APTMAC), methacrylamidopropyl trimethyl ammonium chloride (MPTMAC), quaternized N-vinylpyridine, quaternized 2-vinylpyridine, quaternized 4-vinylpyridine.

(26) As mentioned above regarding the first monomer component, “X” can represent a halide, pseudohalide, or a sulfate. Preferred halides are chloride and bromide. A pseudohalide is an anion that shares common structural and electronic features with the halides. Examples include cyanide, thiocyanate, azidothiocarbonate, selenocyanate, tellurocyanate, cyanate, azide, and their structural isomers.

(27) Monomer component (B) can be chosen, for example, from acrylonitrile, methacrylonitrile, vinyl acetate, vinyl propionate, vinyl pivalate, vinyl butyrate, vinyl methacrylate, vinyl laurate, vinyl decanoate, styrene, α-methylstyrene, 3-methylstyrene, 4-methylstyrene, 4-tert-butylstyrene, 2,4-dimethylstyrene, 2,4,6-trimethylstyrene, vinyl ethyl ether, vinyl propyl ether, vinyl butyl ether, vinyl isooctyl ether, vinyl 2-ethylhexyl ether, vinyl dodecyl ether, methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, octyl (meth)acrylate, isodecyl (meth)acrylate, decyl (meth)acrylate, lauryl (meth)acrylate, dodecyl (meth)acrylate, tetradecyl (meth)acrylate, hexadecyl (meth)acrylate, octadecyl (meth)acrylate, N-dodecyl (meth)acrylamide, N-tert-octyl (meth)acrylamide, and N-1-hexyl (meth)acrylamide.

(28) Monomer component (C) can be chosen, for example, from a group including acrylamide, methacrylamide, N-methyl acrylamide, N-methyl methacrylamide, N-methylol acrylamide, N-methylol methacrylamide, N-isopropyl acrylamide, N,N-dimethyl acrylamide, N,N-dimethyl methacrylamide, N-vinyl pyrrolidone, 2-vinyl pyridine, 4-vinyl pyridine, N-vinyl pyridine, polyalkyleneoxide acrylate, polyalkyleneoxide methacrylate, and polyalkyleneoxide ether.

(29) In preferred embodiments of the invention, the molar ratio (A:B) of monomer component (A) to monomer component (B) is 0.60:0.40 to 0.98:0.02; and, more preferably, the molar ratio (A:B) is 0.75:0.25 to 0.95:0.05.

(30) In other preferred embodiments, R.sub.7 and R.sub.8 of the above-described copolymer are —CH.sub.3; and R.sub.9 and R.sub.10 of said copolymer are hydrogen.

(31) In other preferred embodiments, Z.sub.1 is oxygen and Y.sub.1 is —CH.sub.2CH.sub.2—.

(32) In still further embodiments, Z.sub.1 is —NH— and Y.sub.1 is —CH.sub.2CH.sub.2CH.sub.2—.

(33) In other embodiments of the invention, the above-described copolymer may contain two or more monomer components which are both represented by the structure of the first monomer (A). In other embodiments of the invention, the copolymer may contain two or more monomer components which are both represented by the structure of the second monomer (B).

(34) In preferred embodiments of the invention, the copolymer has a Brookfield viscosity of 5 to 500 Centipoise (hereinafter “cps”) at 30 wt % aqueous solution at 20 degrees C.; and, more preferably, the copolymer has a Brookfield viscosity of 10 to 200 cps at 30 wt % aqueous solution at 20 degrees C.

(35) Preferably, in methods and compositions of the invention, the amount of the copolymer introduced to the clay is 5% to 40%, and more preferably 8% to 20% by weight, based on the weight of the clay being treated.

(36) In one exemplary method of the invention, the sand treated by the copolymer may then be combined with the components for making concrete, mortar, or asphalt. The present invention also relates to concrete, mortar, or asphalt containing the sand, clay, and above-described copolymer. The copolymer may be introduced to the sand by application to the clay-containing aggregates at the quarry or mine, or at the concrete mix plant where the aggregates are combined with cement to form hydratable mortar or concrete. The copolymer may be incorporated into the aggregates at the concrete mix plant before the cement binder is added, or into dry or wet mortar or concrete.

(37) Thus, the invention also provides chemical admixtures containing the copolymer described above as well as to aggregate compositions, cementitious compositions, and concrete compositions containing the hydrophobicaly modified cationic copolymer. It is contemplated that conventional chemical admixtures may be used in combination with the above-described copolymer in exemplary methods, admixture compositions, cementitious compositions, aggregate compositions, and concrete compositions of the invention. Such conventional admixtures may include for example, lignin sulfonate, naphthalene sulfonate formaldehyde condensate (NSFC), melamine sulfonate formaldehyde condensate (MSFC), polycarboxylate polymer cement dispersants (such as the ethylene oxide/propylene oxide (EO/PO) type described above), gluconate, set retarders, set accelerators, defoamers, air entraining agents, surface active agents, or mixtures thereof.

(38) Hence, the present invention also provides chemical admixture compositions comprising the above-mentioned copolymer in combination with at least one conventional admixture, such as water reducing admixtures (e.g., superplasticizers), defoamers, air entraining agents, surfactants, or mixtures thereof.

(39) Exemplary cement and cementitious compositions, aggregate compositions, and concrete compositions of the invention contain the hydrophobically-modified cationic polymer derived from the aforementioned monomer components (A), (B), and optionally (C). Thus, exemplary cementitious compositions of the invention comprise at least one hydratable cement binder in combination with the above-described copolymer for treating clay, and optionally aggregates containing clay which requires the treatment described herein. Exemplary aggregate compositions of the invention comprise sand aggregate in combination with the above-described hydrophobically-modified cationic polymer. The sand aggregate may contain clay which requires treatment by the above-described hydrophobically-modified cationic polymer, or it may be added to sand aggregate that contains the clay which requires said treatment. Exemplary concrete compositions of the invention comprise aggregate containing the clay which requires the treatment, cement, and the above-described hydrophobically-modified cationic polymer

(40) 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. All parts and percentages in the examples, as well as in the remainder of the specification, are by percentage weight unless otherwise specified.

Example 1

(41) A diallyl dimethyl ammonium chloride (DADMAC) monomer aqueous solution (78.8 g, 65% active), n-propanol (40 ml), and distilled water (50 ml) were transferred into a 500 ml flask equipped with a condenser, a mechanical stirrer, a thermocouple and a nitrogen inlet. The system was purged with nitrogen gas to remove air, and the solution temperature was increased to 70 degrees C. Into the flask, three solutions, 55 g of DADMAC monomer aqueous solution (65% active), a solution of 1 ml of 3-mercaptopropionic acid, 11 g of 2-ethyhexyl acrylate (2-EHA, 11 g) in 49 ml n-propanol, and 40 ml aqueous solution of ammonium persulfate (9.12 g) were added into the flask simultaneously over a period of 8 hours. After addition, the reaction was held at 70° C. for 12 hours, then stopped by cooling to ambient temperature. The resulting material is called Polymer A.

(42) Using the same procedure, the following polymers were synthesized and summarized in Table 1.

(43) TABLE-US-00001 TABLE 1 Cationic polymers synthesized via procedure described in Example 1 Hydrophobic DADMAC monomer Brookfield (wt %) Type.sup.a) wt % Viscosity.sup.b) Polymer A 78 2-EHA 22 48 Polymer B 89 2-EHA 11 21 Polymer C 74 t-BA 26 104  Polymer D 84 t-BA 16 65 Polymer E 92 t-BA 8 31 Polymer F 95 BMA 5 NA Polymer G 95 MMA 5 NA Reference-1 100 none 0 36 .sup.a)2-EHA: 2-ethylhexyl acrylate; t-BA: tert-butyl acrylate; BMA, n-butyl methacrylate; MMA: methyl methacrylate. .sup.b)Brookfield viscosity was measured at 30 wt % solution, 20° C. using spindle S61 on model DV-II+ Brookfield viscometer.

Example 2

(44) Another exemplary polymer (Polymer H) was synthesized as follows. Degassed water (50 ml) and n-propanol (50 ml) were charged into a 500 ml flask equipped with a condenser, a mechanical stirrer, a thermocouple and a nitrogen inlet. The system was then purged with nitrogen gas and heated to 70° C. Into the flask, three solutions, 112.5 g of 2-(methacryloyloxy)ethyl trimethylammonium chloride (METAC) monomer aqueous solution (80 wt % active), a solution of 1 ml of 3-mercaptopropionic acid, 10 g of t-butyl acrylate (t-BA) in 50 ml n-propanol, and 40 ml aqueous solution of ammonium persulfate (7.77 g) were added into the flask simultaneously over a period of 8 hours. After addition, the reaction was hold at 70° C. for 12 hours then stopped by cooling to ambient temperature. The resulting material is called Polymer H.

(45) Using the above descried procedure, the following polymers were synthesized and summarized in Table 2.

(46) TABLE-US-00002 TABLE 2 Cationic copolymer synthesized via procedure described in Example 2. METAC t-BA Brookfield (wt %) (wt %) Viscosity.sup.a) Polymer H 90 10 26 Polymer I 95 5 22 Reference-2 100 0 15 .sup.a)Brookfield viscosity was measured at 30 wt % solution, 20° C. using spindle S61 on model DV-II+ Brookfield viscometer.

Example 3

(47) The effects of Polymers A, B, C, D and E on mortar workability were tested against the Reference-1, which is a homopolymer of DADMAC synthesized using the same procedure. The mortar test results are illustrated in Table 2. Mortar was prepared in the traditional manner and was formulated as follows for 10 wt % treatment dosage: sand (1350 g), cement (650 g), sodium montmorillonite (2.7 g), water (240 g), 1.95 g of 40 wt % aqueous polycarboxylate superplasticizer (0.12% active by weight of cement), and 2.7 g of 10 wt % aqueous polymer solution of this invention. The aqueous polymer solution of this invention was added to a pre-blended mixture of sodium montmorillonite and sand, followed by addition of cement water and polycarboxylate superplastisizer. The workability of mortar was determined by measuring the slump and flow and was calculated by the following equation, workability=slump+(flow 1+flow 2)/2−100.

(48) TABLE-US-00003 TABLE 3 Mortar workability test wt % on sodium w/c Workability montmorillonite ratio (mm) Polymer A 10 0.37 215 Polymer B 10 0.37 181 Polymer C 10 0.37 178 Polymer D 10 0.37 190 Polymer E 10 0.37 198 Reference-1 10 0.37 178 Polymer A 25 0.36 208 Polymer B 25 0.36 227 Polymer C 25 0.36 209 Polymer D 25 0.36 241 Polymer E 25 0.36 231 Reference-1 25 0.36 190

(49) As shown in Table 3, at equal w/c ratio and polymer dosage, the hydrophobically modified Polymers A, B, C, D and E exhibited higher workability as compared to the unmodified polymer (Reference-1), indicating the effectiveness of these materials as clay mitigating agents.

Example 4

(50) The performance of the Polymers F and G were evaluated by mortar test. The test procedure of Example 3 was employed except that the workability was measured as a function of time. The mortar workability performance results of mortars containing the polymers are summarized below in Table 4.

(51) TABLE-US-00004 TABLE 4 Mortar workability test Wt % on sodium Workability (mm) montmorillonite 4 min. 30 min. 60 min. Polymer F 6% 203 158 85 Polymer G 6% 215 153 81 Reference-1 6% 206 138 60 Reference 0 140 30 20
The results in Table 4 indicate that the polymer of this invention clearly enhanced workability retention of the mortar.

Example 5

(52) The performance of the Polymer I was evaluated by mortar test against Reference-2 following the test protocol described in Example 3 except that the polymer of this invention was used at 15 weight percent based on the weight of sodium montmorillonite. The results of mortar workability performance is shown below in Table 5.

(53) TABLE-US-00005 TABLE 5 Mortar Workability Test Workability (mm) 9 min. 30 min. 60 min. Polymer I 290 223 165 Reference-2 257 199 135
As shown in Table 5, incorporation of hydrophobic monomers was seen to enhance workability of the mortar.

Example 6

(54) The effects of the Polymers B and D on concrete slump were tested against Reference-1, which is a homopolymer of DADMAC.

(55) Concrete was prepared in the traditional manner as follows: sand (1374 lb/yd3), stone (1800 lb/yd3), cement X (Ordinary Portland Cement, 658 lb/yd3), water (42 wt % based on cement), sodium montmorillonite (2.75 lb/yd3), polycarboxylate superplasticizer (0.135% active by weight of cement), and the polymers of this invention were added at 30 wt % active based on the weight of sodium montmorillonite. Sand was blended with sodium montmorillonite and then mixed with the cationic polymer prior to mixing into the concrete. The performance of the sand containing the polymers is shown below in Table 6.

(56) TABLE-US-00006 TABLE 6 Concrete slump test Concrete slump (inch) at 9 min 30 min 50 min Polymer B 24.50 19.25 16.25 Polymer D 24.75 19.25 16.75 Reference-1 21.75 18.00 NA
As shown in Table 6, both Polymer B and D outperformed Reference-1 in providing higher initial slump and higher slump over time.

Example 7

(57) The effects of the Polymers B and D on concrete slump and slump retention were also evaluated against Reference-1 using a different cement. The test protocol of Example 6 was employed except that cement X was replaced with cement Y, also an OPC.

(58) TABLE-US-00007 TABLE 7 Concrete slump test Concrete slump (inch) at Entry 9 min 30 min 50 min Polymer B 25.25 22.25 19.25 Polymer D 26.00 21.25 16.75 Reference-1 21.00 19.50 16.75

(59) The higher slumps for both Polymer B and D shown in Table 7 confirm that the polymers of this invention performed as effective clay mitigating agents.

Example 8

(60) The effects of the Polymer H on concrete slump were tested against Reference-2, which is a homopolymer of METAC, using the test protocol of Example 6 and OPC cement Z. The concrete slump test results are tabulated in Table 8.

(61) TABLE-US-00008 TABLE 8 Concrete slump test Concrete slump (inch) at 9 min 30 min 50 min Polymer H 24.25 19.25 18.00 Reference-2 24.75 17.75 16.50

(62) As shown in Table 8, although the initial slumps of Polymer H and Reference-2 are comparable, Polymer G is capable of maintaining a higher slump than Reference-2 over time, indicating its effectiveness as a clay mitigating polymer.

(63) The foregoing examples and embodiments were presented for illustrative purposes only and not intended to limit the scope of the invention.