WO2017214108A1 - Strength enhancing admixtures for hydraulic cements - Google Patents
Strength enhancing admixtures for hydraulic cements Download PDFInfo
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- WO2017214108A1 WO2017214108A1 PCT/US2017/036101 US2017036101W WO2017214108A1 WO 2017214108 A1 WO2017214108 A1 WO 2017214108A1 US 2017036101 W US2017036101 W US 2017036101W WO 2017214108 A1 WO2017214108 A1 WO 2017214108A1
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- hydrogen atom
- cement
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- hydraulic
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Links
- 239000011396 hydraulic cement Substances 0.000 title claims description 36
- 230000002708 enhancing effect Effects 0.000 title description 5
- 239000004568 cement Substances 0.000 claims abstract description 83
- 239000000203 mixture Substances 0.000 claims abstract description 83
- -1 glycol ether acetates Chemical class 0.000 claims abstract description 10
- 125000004435 hydrogen atom Chemical group [H]* 0.000 claims description 49
- 239000004567 concrete Substances 0.000 claims description 41
- 239000000463 material Substances 0.000 claims description 38
- 239000004570 mortar (masonry) Substances 0.000 claims description 33
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 28
- 238000000034 method Methods 0.000 claims description 28
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 27
- 238000002156 mixing Methods 0.000 claims description 24
- 239000011398 Portland cement Substances 0.000 claims description 22
- 239000000126 substance Substances 0.000 claims description 18
- 125000002887 hydroxy group Chemical group [H]O* 0.000 claims description 7
- 125000000217 alkyl group Chemical group 0.000 claims description 6
- 239000000377 silicon dioxide Substances 0.000 claims description 6
- 229910021532 Calcite Inorganic materials 0.000 claims description 5
- 235000019738 Limestone Nutrition 0.000 claims description 5
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 claims description 5
- QXJJQWWVWRCVQT-UHFFFAOYSA-K calcium;sodium;phosphate Chemical compound [Na+].[Ca+2].[O-]P([O-])([O-])=O QXJJQWWVWRCVQT-UHFFFAOYSA-K 0.000 claims description 5
- 239000010433 feldspar Substances 0.000 claims description 5
- 239000010438 granite Substances 0.000 claims description 5
- 239000006028 limestone Substances 0.000 claims description 5
- 239000004579 marble Substances 0.000 claims description 5
- 239000010453 quartz Substances 0.000 claims description 5
- 230000000717 retained effect Effects 0.000 claims description 5
- XEKOWRVHYACXOJ-UHFFFAOYSA-N Ethyl acetate Chemical compound CCOC(C)=O XEKOWRVHYACXOJ-UHFFFAOYSA-N 0.000 abstract description 9
- NQBXSWAWVZHKBZ-UHFFFAOYSA-N 2-butoxyethyl acetate Chemical compound CCCCOCCOC(C)=O NQBXSWAWVZHKBZ-UHFFFAOYSA-N 0.000 abstract description 4
- 230000036571 hydration Effects 0.000 description 12
- 238000006703 hydration reaction Methods 0.000 description 12
- 239000004576 sand Substances 0.000 description 11
- BCAARMUWIRURQS-UHFFFAOYSA-N dicalcium;oxocalcium;silicate Chemical compound [Ca+2].[Ca+2].[Ca]=O.[O-][Si]([O-])([O-])[O-] BCAARMUWIRURQS-UHFFFAOYSA-N 0.000 description 10
- 229910021534 tricalcium silicate Inorganic materials 0.000 description 10
- 235000019976 tricalcium silicate Nutrition 0.000 description 10
- 230000008569 process Effects 0.000 description 6
- 230000001603 reducing effect Effects 0.000 description 6
- 230000001133 acceleration Effects 0.000 description 5
- 239000000654 additive Substances 0.000 description 5
- 239000012071 phase Substances 0.000 description 5
- 230000015572 biosynthetic process Effects 0.000 description 4
- 239000011575 calcium Substances 0.000 description 4
- AXCZMVOFGPJBDE-UHFFFAOYSA-L calcium dihydroxide Chemical compound [OH-].[OH-].[Ca+2] AXCZMVOFGPJBDE-UHFFFAOYSA-L 0.000 description 4
- 238000006243 chemical reaction Methods 0.000 description 4
- 238000005336 cracking Methods 0.000 description 4
- QTBSBXVTEAMEQO-UHFFFAOYSA-M Acetate Chemical compound CC([O-])=O QTBSBXVTEAMEQO-UHFFFAOYSA-M 0.000 description 3
- OYPRJOBELJOOCE-UHFFFAOYSA-N Calcium Chemical compound [Ca] OYPRJOBELJOOCE-UHFFFAOYSA-N 0.000 description 3
- 229910052791 calcium Inorganic materials 0.000 description 3
- 239000003638 chemical reducing agent Substances 0.000 description 3
- 239000013068 control sample Substances 0.000 description 3
- 238000011161 development Methods 0.000 description 3
- MTHSVFCYNBDYFN-UHFFFAOYSA-N diethylene glycol Chemical compound OCCOCCO MTHSVFCYNBDYFN-UHFFFAOYSA-N 0.000 description 3
- 238000004090 dissolution Methods 0.000 description 3
- 230000006698 induction Effects 0.000 description 3
- 239000004615 ingredient Substances 0.000 description 3
- 230000007246 mechanism Effects 0.000 description 3
- 230000009467 reduction Effects 0.000 description 3
- 238000012360 testing method Methods 0.000 description 3
- 229910000831 Steel Inorganic materials 0.000 description 2
- 230000000996 additive effect Effects 0.000 description 2
- 150000001412 amines Chemical class 0.000 description 2
- 239000000920 calcium hydroxide Substances 0.000 description 2
- 229910001861 calcium hydroxide Inorganic materials 0.000 description 2
- 235000011116 calcium hydroxide Nutrition 0.000 description 2
- 230000015556 catabolic process Effects 0.000 description 2
- 239000004035 construction material Substances 0.000 description 2
- 230000007797 corrosion Effects 0.000 description 2
- 238000005260 corrosion Methods 0.000 description 2
- 238000006731 degradation reaction Methods 0.000 description 2
- 239000000835 fiber Substances 0.000 description 2
- 239000012530 fluid Substances 0.000 description 2
- 238000009472 formulation Methods 0.000 description 2
- 230000001965 increasing effect Effects 0.000 description 2
- 238000005259 measurement Methods 0.000 description 2
- 125000005702 oxyalkylene group Chemical group 0.000 description 2
- 239000000049 pigment Substances 0.000 description 2
- 239000011148 porous material Substances 0.000 description 2
- 238000002360 preparation method Methods 0.000 description 2
- 230000002035 prolonged effect Effects 0.000 description 2
- 239000000523 sample Substances 0.000 description 2
- 239000002893 slag Substances 0.000 description 2
- 239000007787 solid Substances 0.000 description 2
- 241000894007 species Species 0.000 description 2
- 239000010959 steel Substances 0.000 description 2
- 125000000008 (C1-C10) alkyl group Chemical group 0.000 description 1
- 241000196324 Embryophyta Species 0.000 description 1
- SLINHMUFWFWBMU-UHFFFAOYSA-N Triisopropanolamine Chemical compound CC(O)CN(CC(C)O)CC(C)O SLINHMUFWFWBMU-UHFFFAOYSA-N 0.000 description 1
- 238000007792 addition Methods 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- 239000012615 aggregate Substances 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- 230000008901 benefit Effects 0.000 description 1
- 239000011230 binding agent Substances 0.000 description 1
- 229910052918 calcium silicate Inorganic materials 0.000 description 1
- JHLNERQLKQQLRZ-UHFFFAOYSA-N calcium silicate Chemical compound [Ca+2].[Ca+2].[O-][Si]([O-])([O-])[O-] JHLNERQLKQQLRZ-UHFFFAOYSA-N 0.000 description 1
- 235000012241 calcium silicate Nutrition 0.000 description 1
- 239000003153 chemical reaction reagent Substances 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 230000000536 complexating effect Effects 0.000 description 1
- 239000002131 composite material Substances 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 239000000470 constituent Substances 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 238000002425 crystallisation Methods 0.000 description 1
- 230000008025 crystallization Effects 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 230000002939 deleterious effect Effects 0.000 description 1
- HOOWDPSAHIOHCC-UHFFFAOYSA-N dialuminum tricalcium oxygen(2-) Chemical compound [O--].[O--].[O--].[O--].[O--].[O--].[Al+3].[Al+3].[Ca++].[Ca++].[Ca++] HOOWDPSAHIOHCC-UHFFFAOYSA-N 0.000 description 1
- 238000009792 diffusion process Methods 0.000 description 1
- 239000002270 dispersing agent Substances 0.000 description 1
- 230000009429 distress Effects 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 239000010881 fly ash Substances 0.000 description 1
- 230000000855 fungicidal effect Effects 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 230000002070 germicidal effect Effects 0.000 description 1
- 239000010440 gypsum Substances 0.000 description 1
- 229910052602 gypsum Inorganic materials 0.000 description 1
- 230000000887 hydrating effect Effects 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 239000003112 inhibitor Substances 0.000 description 1
- 229910052500 inorganic mineral Inorganic materials 0.000 description 1
- 230000000749 insecticidal effect Effects 0.000 description 1
- 238000002334 isothermal calorimetry Methods 0.000 description 1
- 238000002386 leaching Methods 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 238000012423 maintenance Methods 0.000 description 1
- 239000011159 matrix material Substances 0.000 description 1
- 239000011707 mineral Substances 0.000 description 1
- 235000010755 mineral Nutrition 0.000 description 1
- 239000011412 natural cement Substances 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 230000035699 permeability Effects 0.000 description 1
- 230000000704 physical effect Effects 0.000 description 1
- 239000004033 plastic Substances 0.000 description 1
- 229920005646 polycarboxylate Polymers 0.000 description 1
- 238000001556 precipitation Methods 0.000 description 1
- 238000005086 pumping Methods 0.000 description 1
- 239000000376 reactant Substances 0.000 description 1
- 230000009257 reactivity Effects 0.000 description 1
- 239000011150 reinforced concrete Substances 0.000 description 1
- 230000002787 reinforcement Effects 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 238000004904 shortening Methods 0.000 description 1
- 239000007790 solid phase Substances 0.000 description 1
- 238000001179 sorption measurement Methods 0.000 description 1
- 239000004575 stone Substances 0.000 description 1
- 230000035882 stress Effects 0.000 description 1
- 230000007704 transition Effects 0.000 description 1
- 239000002023 wood Substances 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B24/00—Use of organic materials as active ingredients for mortars, concrete or artificial stone, e.g. plasticisers
- C04B24/04—Carboxylic acids; Salts, anhydrides or esters thereof
- C04B24/045—Esters, e.g. lactones
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B28/00—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements
- C04B28/02—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements containing hydraulic cements other than calcium sulfates
- C04B28/04—Portland cements
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B2111/00—Mortars, concrete or artificial stone or mixtures to prepare them, characterised by specific function, property or use
- C04B2111/70—Grouts, e.g. injection mixtures for cables for prestressed concrete
Definitions
- the present invention relates to strength enhancing admixtures for hydraulic cements and methods of making the same. More particularly, this invention relates to chemicals of the glycol ether acetate family for which compressive strength enhancement is demonstrated in hydraulic cement concrete. These admixtures of the glycol ether acetate family have also shown some shrinkage reducing activity in hydraulic cement concrete.
- Concrete is a composite material that primarily consists of hydraulic cement, aggregates such as sand and stone, and water.
- concrete is one of the most affordable construction materials and is used twice (on a volume basis) as much as the sum of all other construction materials, including steel, aluminum, wood, and plastic.
- Hydraulic cement an essential part of concrete, is the matrix and binder for the aggregate material.
- the properties and overall performance of concrete depends on many factors including the chemical composition of the cement, the relative properties of the constituent materials, the physical and chemical nature of the aggregates, the way in which the fluid mixture was process and placed, and the curing conditions among other factors.
- One of the major hydraulic cements is Portland cement.
- Ordinary portland cement (OPC) is a mixture of synthetic and natural mineral phases including tricalcium silicate, dicalcium silicate, tricalcium aluminate, tetra calcium ferrate and gypsum along with much smaller amounts of other phases.
- tricalcium silicate comprises the majority (50-75%) in OPC and it is the phase primarily responsible for the ultimate strength of hydrated-cement pastes.
- stage (I) as soon as tricalcium silicate comes into contact with water, calcium and hydroxyl ions are released into the solution. Thus, this state represents initial dissolution of the tricalcium silicate.
- stage (II) the reaction becomes very slow therefore it is referred to as the dormant or induction stage. In this stage, dissolution of calcium and hydroxyl ions continues but at a very slow rate.
- Stage (III) involves initial crystallization (precipitation) of calcium hydroxide and acceleration in the rate of hydration of tricalcium silicate. Thus, this stage is called the acceleration stage.
- the mechanism that causes the end of induction and the onset of acceleration is largely unknown.
- Stage (IV) is characterized by continuous formation of the hydration products (CH and C-S-H). Likewise, the onset of stage (IV) hydration is largely unknown.
- stage (V) the reaction continues with the slower rates for a prolonged period of time likely caused by the reaction becoming diffusion controlled.
- Shrinkage is a major disadvantage of hydraulic cement concrete during the hydration (curing) process.
- shrinkage frequently produces cracking when the concrete is restrained, such as with steel reinforcements or aggregate material.
- This form of shrinkage cracking is a common source of distress in concrete structures. These cracks serve to accelerate other forms of damage in concrete including corrosion, freeze-thaw related degradation and leaching of soluble hydration products, thereby altering the structural integrity and shortening the service life of the structure.
- a chemical admixture can be defined as an organic or inorganic (solid or liquid) chemical that is added to concrete before or during its mixing to alter or control property development.
- Admixtures can alter the properties of concrete by many mechanisms including but not limited to: reduction in surface tension of water in the pores of concrete; adsorption onto various solid surfaces; altering the solubility of one or more species; and complexing with various soluble species.
- the present invention provides a cement admixture composition for cementitious compositions comprising the chemical structure:
- R, R', and R" are each the same or different and selected from the group consisting of a hydrogen atom, a C 1-10 alkyl group, and a hydroxyl group (OH), and n represents an integer from 1 to 4.
- the present invention provides a cement admixture as in any of the forgoing embodiments, wherein R is a hydrogen atom, R' is a hydrogen atom, R" is a hydrogen atom, and n is 1.
- the present invention provides a cement admixture composition of any of the forgoing embodiments, wherein R is a hydrogen atom, R' is a hydrogen atom, R" is a hydrogen atom, and n is 2. [0016] In a fourth embodiment, the present invention provides a cementitious composition comprising a hydraulic cementitious mix; an aggregate material; water; and a cement admixture comprising the chemical structure:
- R, R', and R" are each the same or different and selected from the group consisting of a hydrogen atom, a Ci-io alkyl group, and a hydroxyl group (OH), and n represents an integer from 1 to 4.
- the present invention provides a cementitious composition of any foregoing embodiments, wherein R is a hydrogen atom, R' is a hydrogen atom, R" is a hydrogen atom, and n is 1 for the cement admixture.
- the present invention provides a cementitious composition of any foregoing embodiments, wherein R is a hydrogen atom, R' is a hydrogen atom, R" is a hydrogen atom, and n is 2 for the cement admixture.
- the present invention provides a cementitious composition of any foregoing embodiments, wherein the hydraulic cementitious mix is selected from the group consisting of portland cement concretes, grouts and mortars; high alumina cement concretes, grouts and mortars; and dry mixes for making such concretes, grouts, and mortars.
- the hydraulic cementitious mix is selected from the group consisting of portland cement concretes, grouts and mortars; high alumina cement concretes, grouts and mortars; and dry mixes for making such concretes, grouts, and mortars.
- the present invention provides a cementitious composition of any foregoing embodiments, wherein the aggregate material is selected from the group consisting of fine aggregate materials that almost entirely pass through a Number 4 sieve according to ASTM C 125 and ASTM C 33, or coarse aggregate materials that are retained on a Number 4 sieve according to ASTM C 125 and ASTM C 33.
- the present invention provides a cementitious composition of any foregoing embodiments, wherein the course aggregate material is selected from the group consisting of silica, quartz, crushed round marble, glass spheres, granite, limestone, calcite, feldspar, alluvial sands, sands or any other durable aggregate, and mixtures thereof.
- the present invention provides a method of preparing a cementitious composition comprising: mixing water; aggregate material; hydraulic cement; and a cement admixture comprising the chemical structure:
- R, R', and R" are each the same or different and selected from the group consisting of a hydrogen atom, a Ci-io alkyl group, and a hydroxyl group (OH), and n represents an integer from 1 to 4.
- the present invention provides a method as in any of the forgoing embodiments, wherein said step of mixing includes: adding the water, aggregate material, and cement admixture together to form a pre-mixture; and mixing the pre-mixture together with the hydraulic cement to form the cementitious composition.
- the present invention provides a method as in any of the forgoing embodiments, wherein the pre-mixture contains from 0.5 wt % or more to 4 wt% or less of the cement admixture for every one part of the hydraulic cement.
- the present invention provides a method as in any of the foregoing embodiments, wherein the pre-mixture contains from 0.30 or more to about 0.60 or less parts of water for every one part of the hydraulic cement, and from 0.30 or more to about 0.70 or less parts of the aggregate material for every one part of the hydraulic cement.
- the present invention provides a method as in any of the foregoing embodiments, wherein R is a hydrogen atom, R' is a hydrogen atom, R" is a hydrogen atom, and n is 1 for the cement admixture.
- the present invention provides a method as in any of the foregoing embodiments, wherein R is a hydrogen atom, R' is a hydrogen atom, R" is a hydrogen atom, and n is 2 for the cement admixture.
- the present invention provides a method as in any of the foregoing embodiments, wherein the hydraulic cementitious mix is selected from the group consisting of portland cement concretes, grouts and mortars; high alumina cement concretes, grouts and mortars; and dry mixes for making such concretes, grouts, and mortars.
- the present invention provides a method as in any of the foregoing embodiments, wherein the aggregate material is selected from the group consisting of fine aggregate materials that almost entirely pass through a Number 4 sieve according to ASTM C 125 and ASTM C 33, or coarse aggregate materials that are retained on a Number 4 sieve according to ASTM C 125 and ASTM C 33.
- the present invention provides a method as in any of the foregoing embodiments, wherein the aggregate material is course aggregate material and is selected from the group consisting of silica, quartz, crushed round marble, glass spheres, granite, limestone, calcite, feldspar, alluvial sands, sands or any other durable aggregate, and mixtures thereof.
- the aggregate material is course aggregate material and is selected from the group consisting of silica, quartz, crushed round marble, glass spheres, granite, limestone, calcite, feldspar, alluvial sands, sands or any other durable aggregate, and mixtures thereof.
- the present invention provides a method as in any of the foregoing embodiments, wherein mixing in said step of mixing is carried out for between 1 or more and 10 or less minutes.
- An admixture for hydraulic cement mixes is provided, as well as a novel hydraulic cement composition containing such an admixture composition and a method for preparing such a hydraulic cement composition.
- the admixture shows strength enhancing properties, and in some embodiments, shrinkage reducing properties, and in some embodiments both shrinkage reducing and strength-enhancing properties.
- the cement admixture of the present invention is of the following generic chemical structure: wherein R, R', and R" are each the same or different and selected from the group consisting of a hydrogen atom, a Ci-io alkyl group, and a hydroxyl group (OH), and n represents an integer from 1 to 4.
- the cement admixture is 2- butoxyethyl acetate wherein R is a hydrogen atom, R' is a hydrogen atom, R" is a hydrogen atom, and n is 1. This has been shown to reduce shrinkage.
- the cement admixture is 2-2-(butoxyethoxy)ethyl acetate wherein R is a hydrogen atom, R' is a hydrogen atom, R" is a hydrogen atom, and n is 2. This has been shown to reduce shrinkage and increase strength.
- the cement admixture of the present invention is added to hydraulic cement mixes, such as portland cement concretes, grouts and mortars, high alumina cement concretes, grouts and mortars, and dry mixes for making such concretes, grouts, and mortars in amounts sufficient to increase the compressive strength of the hydraulic cement mix and/or to reduce the shrinkage.
- hydraulic cement it is meant those cements that set as a result of a chemical reaction with water.
- the present invention employs a cementitious compositions which has a high content of tricalcium silicate and includes portland cement and cements that are chemically similar or analogous to portland cement, the specification for which is set forth in ASTM specification C 150-00.
- cementitious materials are materials that alone have hydraulic cementing properties, and set and harden in the presence of water. Included in cementitious materials are ground granulated blast-furnace slag, natural cement, hydraulic hydrated lime, and combinations of these and other materials.
- Aggregate can be included in the cementitious formulation to provide mortars including fine aggregate, and concretes including coarse aggregate.
- the fine aggregate are materials that almost entirely pass through a Number 4 sieve (ASTM C 125 and ASTM C 33), such as silica sand.
- the coarse aggregate are materials that are predominantly retained on a Number 4 sieve (ASTM C 125 and ASTM C 33), such as silica, quartz, crushed round marble, glass spheres, granite, limestone, calcite, feldspar, alluvial sands, sands or any other durable aggregate, and mixtures thereof.
- cementitious composition described herein may contain other additives or ingredients and should not be limited to the stated formulations.
- Cement additives that may be added include, but are not limited to: retarders, accelerators, air-entraining or air detraining agents, corrosion inhibitors, pigments, damp- proofing admixtures, gas formers, permeability reducers, pumping aids, fungicidal admixtures, germicidal admixtures, insecticidal admixtures, fibers, alkali-reactivity reducer, bonding admixtures, shrinkage reducing admixtures, pigment and any other admixture or additive that does not adversely affect the properties of the admixture of the present invention.
- strength-enhancing fibers may be used in lesser amounts in light of the strength enhancement resulting from the glycol ether acetate admixtures of this invention.
- the cement admixtures of the present invention have been shown to increase compressive strength in hydraulic cement compositions such as portland cement concretes.
- the cement admixtures of the present invention have also been shown to reduce the surface tension of the pore solution (water remaining in the porosity of hydrating or hydrated cement) and thus inhibit shrinkage under sealed or evaporative drying conditions.
- the cement admixtures of the present invention have less environmental impact and are more workplace safe than existing cement admixtures, such as amine-based compounds.
- the cement admixture of the present invention is introduced into the hydraulic cement composition at the job site or at a ready-mix batching plant as part of the water of hydration.
- the amount of the cement admixture may be governed by factors such as cement type and reactivity, ambient temperature, and concrete mixture proportions.
- the admixture is employed at from 0.5 wt% or more to 4 wt% or less based on the total weight of hydraulic cement added, in other embodiments from about 0.8 wt. % to about 3 wt. %, and in yet other embodiments from about 1 wt. % to about 2 wt. %.
- a mortar mix is prepared by adding from about 0.30 to about 0.60 parts of water for every one part of cement, in other embodiments from about 0.40 to about 0.55 parts of water for every one part of cement, and in yet other embodiments from about 0.45 to about 0.50 parts of water for every one part of cement. In one embodiment, the mortar mix is prepared by adding 0.46 part of water for every one part of cement.
- the mortar mix is prepared by adding from about 0.30 to about 0.70 parts of aggregate sand for every one part of cement, in other embodiments from about 0.40 to about 0.60 parts of aggregate sand for every one part of cement, and in yet other embodiments 0.45 to about 0.55 parts of aggregate sand for every one part of cement. In one embodiment, the mortar mix is prepared by adding 0.5 parts aggregate sand to every one part cement.
- the mortar mix is prepared by adding from about 0.5 wt. % to about 4 wt. % of the cement admixture for every one part of cement, in other embodiments from about 0.8 wt. % to about 3 wt. % of the cement admixture for every one part of cement, and in yet other embodiments from about 1 wt. % to about 2 wt. % of the cement admixture for every one part of cement.
- the mortar mix is prepared by adding 1 wt. % of the cement admixture for every one part of cement.
- the mortar mix is prepared by adding 0.46 parts water to every one part cement, 0.50 parts aggregate sand to every one part cement, and 1 wt. % of the cement admixture to every one part cement.
- the mixing of all the ingredients of the mortar mix including but not limited to water, aggregate sand, the cement admixture of the present invention, and cement, are mixed from about 1 to about 10 minutes, in other embodiments from about 2 to about 8 minutes, and in yet other embodiments from about 3 to about 6 minutes. In one embodiment the mixing is performed for about 4 minutes. In one or more embodiments the mixing takes place on the slowest speed of a commercial stand mixer fit with a mixing hoop.
- the cement admixture is used with an hydraulic cement mixture to create a novel hydraulic cement composition that can be used to increase the strength of an ultimately formed concrete object and/or to reduce the surface tension of the cement so as to reduce shrinkage.
- the hydraulic cement mixture is based on ordinary portland cement, and contains the following ingredients:
- the admixture is added to this portland cement of Table 1 to create the novel hydraulic cement composition,
- the admixture is employed at from 0.5 wt% or more to 4 wt% or less based on the total weight of portland cement, in other embodiments from about 0.8 wt. % to about 3 wt. %, and in yet other embodiments from about 1 wt. % to about 2 wt. % to create portland cement premixtures.
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Ceramic Engineering (AREA)
- Materials Engineering (AREA)
- Structural Engineering (AREA)
- Organic Chemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Inorganic Chemistry (AREA)
- Curing Cements, Concrete, And Artificial Stone (AREA)
Abstract
A cement admixture composition for cementitious compositions is based on glycol ether acetates, and particularly includes 2-butoxyethyl acetate and 2-2-(butoxyethoxy)ethyl acetate. The admixture can enhance the strength of a resultant cementitious composition and reduce shrinkage during curing.
Description
STRENGTH ENHANCING ADMIXTURES FOR HYDRAULIC CEMENTS
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of provisional U.S. Patent Application Serial No. 62/346,008 filed June 6, 2016, and provisional U.S. Patent Application Serial No. 62/419,162 filed November 8, 2016, the contents of which are both herein incorporated by reference.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
[0002] This invention was made with government support under IIP-1343447 awarded by the National Science Foundation. The government has certain rights in the invention.
FIELD OF THE INVENTION
[0003] The present invention relates to strength enhancing admixtures for hydraulic cements and methods of making the same. More particularly, this invention relates to chemicals of the glycol ether acetate family for which compressive strength enhancement is demonstrated in hydraulic cement concrete. These admixtures of the glycol ether acetate family have also shown some shrinkage reducing activity in hydraulic cement concrete.
BACKGROUND OF THE INVENTION
[0004] Concrete is integral to the growth of modern infrastructure. Approximately 200,000 bridges in the United States are constructed of conventional reinforced concrete. Recent figures for the United States showed that the US needs at least $3.6 trillion over a five-year period to improve the overall reliability of its infrastructure from poor to acceptable. This infrastructure maintenance bill is in part caused by crack formation in concrete roads and bridges. While cracking is inevitable with the present state of concrete technology, crack formation unfortunately leads to accelerated degradation, aesthetically unacceptable and difficult to drive on surfaces and eventual failure of the structure.
[0005] Concrete is a composite material that primarily consists of hydraulic cement, aggregates such as sand and stone, and water. In the construction industry, concrete is one of the most affordable construction materials and is used twice (on a
volume basis) as much as the sum of all other construction materials, including steel, aluminum, wood, and plastic.
[0006] Hydraulic cement, an essential part of concrete, is the matrix and binder for the aggregate material. The properties and overall performance of concrete depends on many factors including the chemical composition of the cement, the relative properties of the constituent materials, the physical and chemical nature of the aggregates, the way in which the fluid mixture was process and placed, and the curing conditions among other factors. One of the major hydraulic cements is Portland cement. Ordinary portland cement (OPC) is a mixture of synthetic and natural mineral phases including tricalcium silicate, dicalcium silicate, tricalcium aluminate, tetra calcium ferrate and gypsum along with much smaller amounts of other phases. Among all the reactant phases, tricalcium silicate comprises the majority (50-75%) in OPC and it is the phase primarily responsible for the ultimate strength of hydrated-cement pastes.
[0007] When hydraulic cement is mixed with water, the resulting cement paste begins to stiffen after a period of time. This transition process is characterized as, initial set, final set, and development of strength. These processes are the result of the formation of hydration products, which percolate the solid phases and hold the individual granular components together. Most of the previous studies related to the hydration of hydraulic cement have focused on the hydration of the tricalcium silicate phase because it is the key component and most abundant in OPC. The hydration of tricalcium silicate is an exothermic process and can be monitored continuously using isothermal calorimetry. The hydration process of tricalcium silicate has five distinct stages: (1) dissolution, (II) induction, (III) acceleration, (IV) deceleration, and (V) slow prolonged hydration. In stage (I) as soon as tricalcium silicate comes into contact with water, calcium and hydroxyl ions are released into the solution. Thus, this state represents initial dissolution of the tricalcium silicate. In stage (II), the reaction becomes very slow therefore it is referred to as the dormant or induction stage. In this stage, dissolution of calcium and hydroxyl ions continues but at a very slow rate. Also, foil-like nuclei of C-S-H appear on the tricalcium silicate particle surfaces resulting in lower Ca/Si rations and higher U2O/S1 ratios. Stage (III) involves initial crystallization (precipitation) of calcium hydroxide and acceleration in the rate of hydration of tricalcium silicate. Thus, this stage is called the
acceleration stage. The mechanism that causes the end of induction and the onset of acceleration is largely unknown. Stage (IV) is characterized by continuous formation of the hydration products (CH and C-S-H). Likewise, the onset of stage (IV) hydration is largely unknown. Finally, in stage (V), the reaction continues with the slower rates for a prolonged period of time likely caused by the reaction becoming diffusion controlled.
[0008] Shrinkage is a major disadvantage of hydraulic cement concrete during the hydration (curing) process. In particular, shrinkage frequently produces cracking when the concrete is restrained, such as with steel reinforcements or aggregate material. This form of shrinkage cracking is a common source of distress in concrete structures. These cracks serve to accelerate other forms of damage in concrete including corrosion, freeze-thaw related degradation and leaching of soluble hydration products, thereby altering the structural integrity and shortening the service life of the structure.
[0009] In addition to hydraulic cement, aggregates, and water, various chemical admixtures are frequently used to alter either the fluid or hardened properties of concrete. A chemical admixture can be defined as an organic or inorganic (solid or liquid) chemical that is added to concrete before or during its mixing to alter or control property development. Admixtures can alter the properties of concrete by many mechanisms including but not limited to: reduction in surface tension of water in the pores of concrete; adsorption onto various solid surfaces; altering the solubility of one or more species; and complexing with various soluble species.
[0010] The many and different mechanisms induce various and useful effects such as shrinkage reduction, strength enhancement, set acceleration/retardation, water requirement reduction, decreased or increased viscosity or yield stress, etc. Therefore, chemical admixtures are indispensable materials that are used in formulating and specifying concrete based on application needs, such as to reduce the cost of handling and placing the concrete or to make the hardened material more durable, ultimately reducing the life-cycle cost and improving the life-cycle performance of the concrete.
[0011] There have been previous attempts at creating chemical admixtures in order to enhance the strength of portland cement compositions. US Patent No. 4,318,744 teaches the use of pozzolans such as fly ash and blast furnace slag to
enhance the strength of portland cement compositions. US Patent No. 7,972,435 teaches the use a of polycarboxylate dispersant and amine based strength improvement additives to enhance the strength of portland cement compositions. US Patent No. 5,641,352 teaches the use of a nitrogenous compound to enhance the strength of portland cement compositions. US Patent No. 4,990,190 teaches the use of a strength enhancing additive comprising triisopropanolamine to enhance the strength of portland cement compositions.
[0012] There have also been previous attempt at creating admixtures in order to reduce shrinkage cracking in concrete. U.S. Patent No. 4,547,223 teaches that linear oxyalkylene have been proven to reduce shrinkage. U.S. Patent Nos. 5,556,460 and 5,603,760 teach the use of low molecular weight oxyalkylene compounds as shrinkage reducing agents. There is a continuing need however for alternative and/or improved admixtures. SUMMARY OF THE INVENTION
[0013] In a first embodiment, the present invention provides a cement admixture composition for cementitious compositions comprising the chemical structure:
wherein R, R', and R" are each the same or different and selected from the group consisting of a hydrogen atom, a C 1-10 alkyl group, and a hydroxyl group (OH), and n represents an integer from 1 to 4.
[0014] In a second embodiment, the present invention provides a cement admixture as in any of the forgoing embodiments, wherein R is a hydrogen atom, R' is a hydrogen atom, R" is a hydrogen atom, and n is 1.
[0015] In a third embodiment, the present invention provides a cement admixture composition of any of the forgoing embodiments, wherein R is a hydrogen atom, R' is a hydrogen atom, R" is a hydrogen atom, and n is 2.
[0016] In a fourth embodiment, the present invention provides a cementitious composition comprising a hydraulic cementitious mix; an aggregate material; water; and a cement admixture comprising the chemical structure:
wherein R, R', and R" are each the same or different and selected from the group consisting of a hydrogen atom, a Ci-io alkyl group, and a hydroxyl group (OH), and n represents an integer from 1 to 4.
[0017] In a fifth embodiment, the present invention provides a cementitious composition of any foregoing embodiments, wherein R is a hydrogen atom, R' is a hydrogen atom, R" is a hydrogen atom, and n is 1 for the cement admixture.
[0018] In a sixth embodiment, the present invention provides a cementitious composition of any foregoing embodiments, wherein R is a hydrogen atom, R' is a hydrogen atom, R" is a hydrogen atom, and n is 2 for the cement admixture.
[0019] In a seventh embodiment, the present invention provides a cementitious composition of any foregoing embodiments, wherein the hydraulic cementitious mix is selected from the group consisting of portland cement concretes, grouts and mortars; high alumina cement concretes, grouts and mortars; and dry mixes for making such concretes, grouts, and mortars.
[0020] In an eighth embodiment, the present invention provides a cementitious composition of any foregoing embodiments, wherein the aggregate material is selected from the group consisting of fine aggregate materials that almost entirely pass through a Number 4 sieve according to ASTM C 125 and ASTM C 33, or coarse aggregate materials that are retained on a Number 4 sieve according to ASTM C 125 and ASTM C 33.
[0021] In a ninth embodiment, the present invention provides a cementitious composition of any foregoing embodiments, wherein the course aggregate material is selected from the group consisting of silica, quartz, crushed round marble, glass
spheres, granite, limestone, calcite, feldspar, alluvial sands, sands or any other durable aggregate, and mixtures thereof.
[0022] In a tenth embodiment, the present invention provides a method of preparing a cementitious composition comprising: mixing water; aggregate material; hydraulic cement; and a cement admixture comprising the chemical structure:
C "-€— O - CH2 CH2— O— CH2 H™™€-
wherein R, R', and R" are each the same or different and selected from the group consisting of a hydrogen atom, a Ci-io alkyl group, and a hydroxyl group (OH), and n represents an integer from 1 to 4.
[0023] In an eleventh embodiment, the present invention provides a method as in any of the forgoing embodiments, wherein said step of mixing includes: adding the water, aggregate material, and cement admixture together to form a pre-mixture; and mixing the pre-mixture together with the hydraulic cement to form the cementitious composition.
[0024] In a twelfth embodiment, the present invention provides a method as in any of the forgoing embodiments, wherein the pre-mixture contains from 0.5 wt % or more to 4 wt% or less of the cement admixture for every one part of the hydraulic cement.
[0025] In a thirteenth embodiment, the present invention provides a method as in any of the foregoing embodiments, wherein the pre-mixture contains from 0.30 or more to about 0.60 or less parts of water for every one part of the hydraulic cement, and from 0.30 or more to about 0.70 or less parts of the aggregate material for every one part of the hydraulic cement.
[0026] In a fourteenth embodiment, the present invention provides a method as in any of the foregoing embodiments, wherein R is a hydrogen atom, R' is a hydrogen atom, R" is a hydrogen atom, and n is 1 for the cement admixture.
[0027] In a fifteenth embodiment, the present invention provides a method as in any of the foregoing embodiments, wherein R is a hydrogen atom, R' is a hydrogen atom, R" is a hydrogen atom, and n is 2 for the cement admixture.
[0028] In a sixteenth embodiment, the present invention provides a method as in any of the foregoing embodiments, wherein the hydraulic cementitious mix is selected from the group consisting of portland cement concretes, grouts and mortars; high alumina cement concretes, grouts and mortars; and dry mixes for making such concretes, grouts, and mortars.
[0029] In a seventeenth embodiment, the present invention provides a method as in any of the foregoing embodiments, wherein the aggregate material is selected from the group consisting of fine aggregate materials that almost entirely pass through a Number 4 sieve according to ASTM C 125 and ASTM C 33, or coarse aggregate materials that are retained on a Number 4 sieve according to ASTM C 125 and ASTM C 33.
[0030] In an eighteenth embodiment, the present invention provides a method as in any of the foregoing embodiments, wherein the aggregate material is course aggregate material and is selected from the group consisting of silica, quartz, crushed round marble, glass spheres, granite, limestone, calcite, feldspar, alluvial sands, sands or any other durable aggregate, and mixtures thereof.
[0031] In a nineteenth embodiment, the present invention provides a method as in any of the foregoing embodiments, wherein mixing in said step of mixing is carried out for between 1 or more and 10 or less minutes.
DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS
[0032] An admixture for hydraulic cement mixes is provided, as well as a novel hydraulic cement composition containing such an admixture composition and a method for preparing such a hydraulic cement composition. In some embodiments, the admixture shows strength enhancing properties, and in some embodiments, shrinkage reducing properties, and in some embodiments both shrinkage reducing and strength-enhancing properties.
[0033] The cement admixture of the present invention is of the following generic chemical structure:
wherein R, R', and R" are each the same or different and selected from the group consisting of a hydrogen atom, a Ci-io alkyl group, and a hydroxyl group (OH), and n represents an integer from 1 to 4.
[0034] In one embodiment of the present invention, the cement admixture is 2- butoxyethyl acetate wherein R is a hydrogen atom, R' is a hydrogen atom, R" is a hydrogen atom, and n is 1. This has been shown to reduce shrinkage.
[0035] In another embodiment of the present invention, the cement admixture is 2-2-(butoxyethoxy)ethyl acetate wherein R is a hydrogen atom, R' is a hydrogen atom, R" is a hydrogen atom, and n is 2. This has been shown to reduce shrinkage and increase strength.
[0036] The cement admixture of the present invention is added to hydraulic cement mixes, such as portland cement concretes, grouts and mortars, high alumina cement concretes, grouts and mortars, and dry mixes for making such concretes, grouts, and mortars in amounts sufficient to increase the compressive strength of the hydraulic cement mix and/or to reduce the shrinkage. By hydraulic cement it is meant those cements that set as a result of a chemical reaction with water. In some embodiments, the present invention employs a cementitious compositions which has a high content of tricalcium silicate and includes portland cement and cements that are chemically similar or analogous to portland cement, the specification for which is set forth in ASTM specification C 150-00.
[0037] Cementitious materials are materials that alone have hydraulic cementing properties, and set and harden in the presence of water. Included in cementitious materials are ground granulated blast-furnace slag, natural cement, hydraulic hydrated lime, and combinations of these and other materials.
[0038] Aggregate can be included in the cementitious formulation to provide mortars including fine aggregate, and concretes including coarse aggregate. The fine aggregate are materials that almost entirely pass through a Number 4 sieve (ASTM C 125 and ASTM C 33), such as silica sand. The coarse aggregate are materials that are
predominantly retained on a Number 4 sieve (ASTM C 125 and ASTM C 33), such as silica, quartz, crushed round marble, glass spheres, granite, limestone, calcite, feldspar, alluvial sands, sands or any other durable aggregate, and mixtures thereof.
[0039] The cementitious composition described herein may contain other additives or ingredients and should not be limited to the stated formulations. Cement additives that may be added include, but are not limited to: retarders, accelerators, air-entraining or air detraining agents, corrosion inhibitors, pigments, damp- proofing admixtures, gas formers, permeability reducers, pumping aids, fungicidal admixtures, germicidal admixtures, insecticidal admixtures, fibers, alkali-reactivity reducer, bonding admixtures, shrinkage reducing admixtures, pigment and any other admixture or additive that does not adversely affect the properties of the admixture of the present invention. These will be used, as and when desired, in normal amounts as practiced in the art, except where the properties leant to the resultant cementitious composition by the admixtures of this invention would allow for lesser or more additions. For example, it may be found that strength-enhancing fibers may be used in lesser amounts in light of the strength enhancement resulting from the glycol ether acetate admixtures of this invention.
[0040] The cement admixtures of the present invention have been shown to increase compressive strength in hydraulic cement compositions such as portland cement concretes. The cement admixtures of the present invention have also been shown to reduce the surface tension of the pore solution (water remaining in the porosity of hydrating or hydrated cement) and thus inhibit shrinkage under sealed or evaporative drying conditions. In addition, the cement admixtures of the present invention have less environmental impact and are more workplace safe than existing cement admixtures, such as amine-based compounds.
[0041] In one or more embodiments, the cement admixture of the present invention is introduced into the hydraulic cement composition at the job site or at a ready-mix batching plant as part of the water of hydration. The amount of the cement admixture may be governed by factors such as cement type and reactivity, ambient temperature, and concrete mixture proportions.
[0042] In one or more embodiments, the admixture is employed at from 0.5 wt% or more to 4 wt% or less based on the total weight of hydraulic cement added, in
other embodiments from about 0.8 wt. % to about 3 wt. %, and in yet other embodiments from about 1 wt. % to about 2 wt. %.
[0043] In one embodiment, a mortar mix is prepared by adding from about 0.30 to about 0.60 parts of water for every one part of cement, in other embodiments from about 0.40 to about 0.55 parts of water for every one part of cement, and in yet other embodiments from about 0.45 to about 0.50 parts of water for every one part of cement. In one embodiment, the mortar mix is prepared by adding 0.46 part of water for every one part of cement.
[0044] In addition to water, the mortar mix is prepared by adding from about 0.30 to about 0.70 parts of aggregate sand for every one part of cement, in other embodiments from about 0.40 to about 0.60 parts of aggregate sand for every one part of cement, and in yet other embodiments 0.45 to about 0.55 parts of aggregate sand for every one part of cement. In one embodiment, the mortar mix is prepared by adding 0.5 parts aggregate sand to every one part cement.
[0045] In one or more embodiment, the mortar mix is prepared by adding from about 0.5 wt. % to about 4 wt. % of the cement admixture for every one part of cement, in other embodiments from about 0.8 wt. % to about 3 wt. % of the cement admixture for every one part of cement, and in yet other embodiments from about 1 wt. % to about 2 wt. % of the cement admixture for every one part of cement. In one embodiment the mortar mix is prepared by adding 1 wt. % of the cement admixture for every one part of cement. In one embodiment, the mortar mix is prepared by adding 0.46 parts water to every one part cement, 0.50 parts aggregate sand to every one part cement, and 1 wt. % of the cement admixture to every one part cement.
[0046] In one embodiment, the mixing of all the ingredients of the mortar mix, including but not limited to water, aggregate sand, the cement admixture of the present invention, and cement, are mixed from about 1 to about 10 minutes, in other embodiments from about 2 to about 8 minutes, and in yet other embodiments from about 3 to about 6 minutes. In one embodiment the mixing is performed for about 4 minutes. In one or more embodiments the mixing takes place on the slowest speed of a commercial stand mixer fit with a mixing hoop.
[0047] In one or more embodiments of the present invention, the cement admixture is used with an hydraulic cement mixture to create a novel hydraulic cement composition that can be used to increase the strength of an ultimately formed
concrete object and/or to reduce the surface tension of the cement so as to reduce shrinkage. In one or more embodiments, the hydraulic cement mixture is based on ordinary portland cement, and contains the following ingredients:
Table 1. Properties of ordinary portland cement
The admixture is added to this portland cement of Table 1 to create the novel hydraulic cement composition, In some embodiments using the portland cement of Table 1, the admixture is employed at from 0.5 wt% or more to 4 wt% or less based on the total weight of portland cement, in other embodiments from about 0.8 wt. % to about 3 wt. %, and in yet other embodiments from about 1 wt. % to about 2 wt. % to create portland cement premixtures.
[0048] In light of the foregoing, it should be appreciated that the present invention significantly advances the art by providing a cement admixture for hydraulic cement concrete that is structurally and functionally improved in a number of ways and which can supply both strength-enhancing and shrinkage reducing properties to the formed cement product. While particular embodiments of the invention have been disclosed in detail herein, it should be appreciated that the invention is not limited thereto or thereby inasmuch as variations on the invention herein will be readily appreciated by those of ordinary skill in the art. The scope of the invention shall be appreciated from the claims that follow.
EXAMPLES
[0049] Ordinary type I/I I cement was provided by Buzz Unicom USA (see table 1 above for details of the composition and physical properties of the cement). Pine Bluff Ohio river sand was used as a fine aggregate. All chemicals were purchased as reagent grade materials. The list of chemicals is provided in Table 2 below.
Table 2. List of Chemicals used in Testing
[0050] Sample preparation and compressive strength measurements were conducted based on ASTM standard ASTM C39-14. Mortar mix was prepared by adding 0.46 parts of water for one part of cement and sand with twice the weight of cement. For admixed trials, 1 wt. % admixture for one part of cement was first dissolved in the mix prior to mixing with the cement. The details of mixing ratios are listed in Table 3. The mixing was performed for four minutes on the second slowest speed of a commercial stand mixer fit with a mixing hoop. The prepared mortar paste was cast into 51 x 102 mm cylindrical molds and cured for 24 hours in a humidity chamber at 23.7 °C and 50% relative humidity. After 24 hours, the harden mortar was remolded and kept at 23±1 °C in saturated lime water for seven days.
Table 3. Mixing proportion ratios for control and admixture samples.
[0051] After seven days, the specimens were tested for compressive strength using a hydraulic strength-testing machine. Load was applied continuously at a rate of about 250 lbs/sec. Final maximum load was recorded when the samples fractured completely.
[0052] Sample preparation and compressive strength measurements were conducted based on ASTM standard ASTM C39-14. Mortar mix was prepared by adding 0.46 parts of water for one part of cement and sand with twice the weight of cement. For admixed trials, 1 wt. % admixture for one part of cement was first dissolved in the mix prior to mixing with the cement. The details of mixing ratios are listed in Table 3. The mixing was performed for four minutes on the second slowest speed of a commercial stand mixer fit with a mixing hoop. The prepared mortar paste was cast into 51 x 102 mm cylindrical molds and cured for 24 hours in a humidity chamber at 23.7 °C and 50% relative humidity. After 24 hours, the harden mortar was remolded and kept at 23±1 °C in saturated lime water for seven days.
[0053] The seven day compressive strength data of the 2-butoxy ethyl acetate was compared against the seven-day compressive strength data of the Eclipse 4500 and against the seven day compressive strength data for the control sample, which contained no admixture. The results showed that the 2-butoxy ethyl acetate increased the compressive strength by roughly 12% as compared to the control sample, while the Eclipse 4500 showed a slight deleterious effect on the strength enhancement. Table 4 shows the seven-day compressive strength values and percentage of strength increase or decrease with respect to the control sample.
Table 4. Seven day compressive strength testing data
2 -butoxy 3 Cement 42 + 12% ethyl acetate Mortar
Eclipse 4500 3 Cement 37 - 1.3%
Mortar
* Average of the three replicates
Claims
What is claimed is:
A cement admixture composition for cementitious compositions comprising the chemical structure:
4.
The cement admixture composition of claim 1 wherein R is a hydrogen atom, R' is a hydrogen atom, R" is a hydrogen atom, and n is 1.
The cement admixture composition of claim 1 wherein R is a hydrogen atom, R' is a hydrogen atom, R" is a hydrogen atom, and n is 2.
A cementitious composition comprising:
a. a hydraulic cementitious mix;
b. aggregate material;
c. water; and
d. a cement admixture comprising the chemical structure:
~~
5. The cementitious composition of claim 4 wherein R is a hydrogen atom, R' is a hydrogen atom, R" is a hydrogen atom, and n is 1 for the cement admixture.
6. The cementitious composition of claim 4 wherein R is a hydrogen atom, R' is a hydrogen atom, R" is a hydrogen atom, and n is 2 for the cement admixture.
The cementitious composition of claim 4 wherein the hydraulic cementitious mix is selected from the group consisting of portland cement concretes, grouts and mortars; high alumina cement concretes, grouts and mortars; and dry mixes for making such concretes, grouts, and mortars.
8. The cementitious composition of claim 4 wherein the aggregate material is selected from the group consisting of fine aggregate materials that almost entirely pass through a Number 4 sieve according to ASTM C 125 and ASTM C 33, or coarse aggregate materials that are retained on a Number 4 sieve according to ASTM C 125 and ASTM C 33.
9. The cementitious composition of claim 8 wherein the course aggregate material is selected from the group consisting of silica, quartz, crushed round marble, glass spheres, granite, limestone, calcite, feldspar, alluvial sands, sands or any other durable aggregate, and mixtures thereof.
10. A method of preparing a cementitious composition comprising:
mixing water, aggregate material, hydraulic cement, and a cement admixture comprising the chemical structure:
wherein R, R', and R" are each the same or different and selected from the group consisting of a hydrogen atom, a Ci-io alkyl group, and a hydroxyl group
(OH), and n represents an integer from 1 to 4.
11. The method of claim 10, wherein said step of mixing includes:
adding the water, aggregate material, and cement admixture together to form a pre-mixture; and
mixing the pre-mixture together with the hydraulic cement to form the cementitious composition.
12. The method of claim 11, wherein the pre-mixture contains from 0.5 wt % or more to 4 wt% or less of the cement admixture for every one part of the hydraulic cement.
13. The method of claim 12, wherein the pre-mixture contains from 0.30 or more to about 0.60 or less parts of water for every one part of the hydraulic cement, and from 0.30 or more to about 0.70 or less parts of the aggregate material for every one part of the hydraulic cement.
14. The method of claim 10 wherein R is a hydrogen atom, R' is a hydrogen atom, R" is a hydrogen atom, and n is 1 for the cement admixture.
15. The method of claim 10 wherein R is a hydrogen atom, R' is a hydrogen atom, R" is a hydrogen atom, and n is 2 for the cement admixture.
16. The method of claim 10 wherein the hydraulic cementitious mix is selected from the group consisting of portland cement concretes, grouts and mortars; high alumina cement concretes, grouts and mortars; and dry mixes for making such concretes, grouts, and mortars.
17. The method of claim 10 wherein the aggregate material is selected from the group consisting of fine aggregate materials that almost entirely pass through a Number 4 sieve according to ASTM C 125 and ASTM C 33, or coarse aggregate materials that are retained on a Number 4 sieve according to ASTM C 125 and ASTM C 33.
18. The method of claim 17 wherein the aggregate material is course aggregate material and is selected from the group consisting of silica, quartz, crushed round marble, glass spheres, granite, limestone, calcite, feldspar, alluvial sands, sands or any other durable aggregate, and mixtures thereof.
19. The method of claim 10 wherein mixing in said step of mixing is carried out for between 1 or more and 10 or less minutes.
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EP4119519A1 (en) | 2021-07-12 | 2023-01-18 | Mapei S.p.A. | Strength enhancing admixture for low-carbon cementitious compositions |
EP4353699A1 (en) | 2022-10-12 | 2024-04-17 | Mapei S.p.A. | Low carbon concrete admixture |
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EP3006423A1 (en) * | 2013-05-29 | 2016-04-13 | Silkroad C&T Co., LTD | Macromonomer for preparing cement admixture and method for preparing same, and cement admixture comprising polycarboxylic acid copolymer, derived from macromonomer, and layered double hydroxide and method for preparing same |
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GB1075459A (en) * | 1964-12-04 | 1967-07-12 | Pollycell Products Ltd | Cementitious compositions |
EP3006423A1 (en) * | 2013-05-29 | 2016-04-13 | Silkroad C&T Co., LTD | Macromonomer for preparing cement admixture and method for preparing same, and cement admixture comprising polycarboxylic acid copolymer, derived from macromonomer, and layered double hydroxide and method for preparing same |
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Publication number | Priority date | Publication date | Assignee | Title |
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EP4119519A1 (en) | 2021-07-12 | 2023-01-18 | Mapei S.p.A. | Strength enhancing admixture for low-carbon cementitious compositions |
WO2023285386A1 (en) | 2021-07-12 | 2023-01-19 | Mapei S.P.A. | Strength enhancing admixture for low-carbon cementitious compositions |
EP4353699A1 (en) | 2022-10-12 | 2024-04-17 | Mapei S.p.A. | Low carbon concrete admixture |
WO2024078964A1 (en) | 2022-10-12 | 2024-04-18 | Mapei S.P.A. | Low carbon concrete admixture |
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