WO2013066192A1 - Hardening-accelerator and a method for accelerating the hardening of hydraulic binders and mixtures thereof - Google Patents
Hardening-accelerator and a method for accelerating the hardening of hydraulic binders and mixtures thereof Download PDFInfo
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- WO2013066192A1 WO2013066192A1 PCT/NO2012/050214 NO2012050214W WO2013066192A1 WO 2013066192 A1 WO2013066192 A1 WO 2013066192A1 NO 2012050214 W NO2012050214 W NO 2012050214W WO 2013066192 A1 WO2013066192 A1 WO 2013066192A1
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- hardening
- fly ash
- thiocyanate
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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
- C04B40/00—Processes, in general, for influencing or modifying the properties of mortars, concrete or artificial stone compositions, e.g. their setting or hardening ability
- C04B40/0028—Aspects relating to the mixing step of the mortar preparation
- C04B40/0039—Premixtures of ingredients
-
- 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
-
- 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
- C04B2103/00—Function or property of ingredients for mortars, concrete or artificial stone
- C04B2103/10—Accelerators; Activators
- C04B2103/12—Set accelerators
-
- 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
- C04B2103/00—Function or property of ingredients for mortars, concrete or artificial stone
- C04B2103/10—Accelerators; Activators
- C04B2103/14—Hardening accelerators
-
- 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
- C04B2111/10—Compositions or ingredients thereof characterised by the absence or the very low content of a specific material
- C04B2111/1062—Halogen free or very low halogen-content materials
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
- Y02W30/00—Technologies for solid waste management
- Y02W30/50—Reuse, recycling or recovery technologies
- Y02W30/91—Use of waste materials as fillers for mortars or concrete
Definitions
- Hardening-accelerator and a method for accelerating the hardening of hydraulic binders and mixtures thereof are provided.
- the present invention relates to a hardening accelerator containing no chloride and a method to accelerate the hardening of hydraulic binders, in particular Portland cement and fly ash with high levels of Portland cement replaced by fly ash and mixtures containing hydraulic binders, in particular of mortar and concrete.
- the hardening accelerator is applied for manufacturing of prefabricated elements and accelerating the manufacture of concrete on the construction site.
- Portland cement is a hydraulic binder that is most commonly used in construction.
- Portland cement mainly includes a mixture of calcium silicate and calcium aluminate minerals that can react with water forming a dense, solid paste.
- Portland cement has some drawbacks when used as a binder for concretes. Materials using Portland cement can be degraded by sulphate attack from seawater or drainage water. Steel used in reinforced Portland concrete is corrosive when pH in the system is under a certain level. Some aggregates can cause alkali-silica reactions in the materials using high alkali Portland cement resulting in cracks and degradation.
- Portland cement has higher heat of hydration than other cement types, and therefore it is not suitable for use in some environments. For example, high heat of hydration can cause cracking when Portland cement is used in hot climates.
- Fly ash is a by-product obtained from coal-burning thermal power plant. Fly ash contains mainly glassy, amorphous components including alumina and silica. ASTM C 618-00 has classified fly ash into two classes: Class C and Class F, depending on the total amount of calcium oxide, silica, alumina and ferric oxide content present. Class F contains more than 70% of the above mentioned oxides , but less than 20% lime (CaO). Class C contains less than 70%, but more than 50% of the abovementioned compounds. Class C fly ash generally contains more than 20% lime (CaO). Class F fly ash has pozzolanic properties, which means that it can react with calcium hydroxide in the presence of water to make calcium aluminate and calcium silicate hydrates. Class C fly ash, in addition to having pozzolanic properties, also has hydraulic properties.
- fly ash Replacing one part of Portland cement by fly ash in cement and concrete productions brings some advantages to environment, technology and economy.
- Using fly ash reduces exploitation of natural recourses for Portland cement production such as limestone, clay and consumes industrial by-product. That helps to decrease the amount of CO2 emitting and fuel burnt during cement production. Those contribute to the protection of the environment and lower the price of the cementitious binder used for concrete production.
- Concrete comprising fly ash has improved workability, lower risks of thermal cracking and decreased damages caused by alkali-silica reactions in the system using high alkali Portland cement.
- fly ash has one main drawback originating from its slow pozzolanic reaction in early ages.
- the early compressive strength of hydraulic binders containing Portland cement and fly ash, particularly at high level of Portland replacement can be increased by applying some alkali compounds such as alkali metal hydroxides, alkali sulphate salts, etc to increase the alkalinity of the system.
- alkali compounds such as alkali metal hydroxides, alkali sulphate salts, etc
- the increase in alkalinity helps to activate the pozzolanic reaction of fly ash due to the increased solubility of fly ash in high pH environment (pH > 13).
- the amount of solid alkali substances required to be added into the system to cause a significant accelerating effect is quite high and this will expense the final strength and long term durability of material using this kind of binder.
- KR 200801 1 1645 A describes an accelerator for increasing the fly ash mixing ratio in concrete, comprising polycarboxylic acid salt, triethanol- amine, sodium thiocyanate, glycine, nitrate and water.
- KR 20060018594 A describes non-alkaline accelerators for concrete admixtures.
- US 2004/0244655 A1 relates to an accelerator used for setting and hardening of hydraulic binders.
- the main components of the accelerator are nitrates, aminoalcohols, hydroxyl- carboxylic acids and polyalcohols.
- US 5605571 A discloses an accelerator used for setting and hardening of hydraulic binders containing at least a nitrate- or sulfite component, at least a thiocyanate component, at least an alkanolamine component and at least a carboxylic acid component.
- the new accelerator should contain no chloride and sharply diminish the drawbacks caused by adding high dosages of chemical into binder systems.
- composition of the new accelerator admixture of the present invention includes: at least one inorganic thiocyanate, at least one organic alkanolamine, at least one organic polyol, and optionally water. All these compounds are known individually producing an accelerating effect on hydration of hydraulic binders, but it has been surprisingly found a synergistic effect when they are combined in the proportion of the present invention.
- the accelerator according to the invention contains no chloride.
- the accelerator according to the invention is suitable for accelerating the hardening of hydraulic binders, particularly for binders comprising of Portland cement and fly ash with high proportions of fly ash.
- the accelerator is suitable for manufacturing prefabricated concretes or for accelerating the hardening of concrete produced on the construction site.
- the components of the accelerator according to the invention can be combined and then added together to other ingredients (binders, aggregates, fillers) to make concrete or they can be added separately.
- the accelerator can also be added to mixing water before being added to the mixture of binders and other ingredients.
- Figure 1 Diagram showing rate of heat of hydration in OPC samples with combinations of the components and components individually and sample with no admixture.
- Figure 2 Diagram showing rate of heat of hydration in OPC samples using 2- and 3-component admixture and with no admixture.
- Figure 3 Diagram showing rate of heat of hydration in OPC (70%) and FA (30%) samples to combinations of the components and components individually and sample with no admixture.
- the accelerator according to the invention comprises at least one inorganic thiocyanate, at least one organic alkanolamine, at least one organic polyol and optionally water.
- a preferred thiocyanate is an alkaline thiocyanate, alkaline earth
- thiocyanate or mixtures thereof.
- a preferred example is sodium thiocyanate.
- a preferred alkanolamine is mono-, di-, triethanolamine, triisopropanol- amine, or mixtures thereof. Diethanolamine is especially preferred.
- a preferred polyol is a lower alcohol with carbon chain from C2 to C6, or mixtures thereof. 1 ,2,3-propanetriol (glycerol) is especially preferred.
- the accelerator according to the invention contains from 5 to 50 % by weight of the at least one inorganic thiocyanate, from 1 to 20% by weight of the at least one organic alkanolamine, from 1 to 20 % by weight of the at least one polyol, and any remainder being water.
- the accelerator according to the invention comprises from 10 to 40 % by weight of the at least one inorganic thiocyanate, from 5 to 15 % by weight of the at least one organic alkanolamine, from 5 to 20 % by weight of the at least one polyol , and any remainder being water.
- the accelerator according to the invention is suitable for accelerating the hardening of hydraulic binders, particularly for binders comprising of Portland cement and fly ash with high proportions of fly ash (>20 % by weight).
- the accelerator is appropriate for manufacturing prefabricated concretes or for accelerating the hardening of concrete produced on the construction site.
- the proportion of fly ash in hydraulic binders can be more than 20 % by weight relative to the total weight of the hydraulic binders.
- the accelerator can be added to hydraulic binders, particularly binders comprising Portland cement and fly ash, in the dosages of from 0.5 to 5 % by weight based on the total weight of the hydraulic binders, more preferably in the dosages of from 1 to 3 % by weight.
- the components of the accelerator according to the invention can be combined in dispersed form in water and then added together to other ingredients (binders, aggregates, fillers) to make concrete or they can be added separately.
- the accelerator according to the invention that was used in the following test mixtures has a composition as disclosed in Table 1 .
- Table 3 shows the effect of the accelerator on the hardening of mortars at 5°C after ageing 2 days and 28 days.
- Table 4 shows the effect of the accelerator on the hardening of mortars at 20°C after ageing 1 day and 28 days.
- Table 6 shows the effect of the accelerator on the hardening of concretes at 5°C after ageing 2 days and 28 days.
- Table 7 shows the effect of the accelerator on the hardening of concretes at 20°C after ageing 18 hours, 2 days and 28 days.
- compositions as disclosed in Table 8 are compositions as disclosed in Table 8:
- Table 9 shows the effect of the accelerator on the hardening of concretes at 5°C after ageing 2 days and 28 days.
- Table 10 shows the effect of the accelerator on the hardening of concretes at 20°C after ageing 18 hours, 2 days and 28 days.
- Table 12 shows the effect of the accelerator on the hardening of concretes at 5°C after ageing 2 days and 28 days.
- Table 13 shows the effect of the accelerator on the hardening of concretes at 20°C after ageing 18 hours, 2 days and 28 days.
- the paste parallels had no admixture (control) and with added NaSCN, DEA, and Glycerol to the water individually with dosages of 0.2%, 0.1 % respectively as well as with the 3- component admixture composed of (0.2% NaSCN + 0.1 % DEA + 0.05% Gly).
- Table 15 The cumulative heat and maximum rate of heat evolution effect of admixture in OPC.
- Table 16 The cumulative heat and maximum rate of heat evolution effect of admixture in OPC (70%) and FA (30%).
- Tables 15 and 16 show that the heat evolutions from the combination of the components are higher than the heat evolutions from the individual components. This synergistic effect is found in Portland cement CEM I and also when 30% of OPC is replaced with fly ash.
- Figures 1 and 3 show how the combination of components affects the heat as function of time. This synergistic effect is clearly shown for the combination of the 3 components admixture in Figure 2.
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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)
- Processing Of Solid Wastes (AREA)
Abstract
Described herein is a novel hardening accelerator including at least one inorganic thiocyanate, at least one alkanolamine, at least one organic polyol and optionally water that accelerates the hardening of hydraulic binders containing Portland cement and in particular Portland cement with a high level of fly ash. Also described herein is a method for accelerating the hardening of hydraulic binders or mixtures containing the hydraulic binders.
Description
Hardening-accelerator and a method for accelerating the hardening of hydraulic binders and mixtures thereof.
Field of the Invention
The present invention relates to a hardening accelerator containing no chloride and a method to accelerate the hardening of hydraulic binders, in particular Portland cement and fly ash with high levels of Portland cement replaced by fly ash and mixtures containing hydraulic binders, in particular of mortar and concrete. The hardening accelerator is applied for manufacturing of prefabricated elements and accelerating the manufacture of concrete on the construction site.
Background of the Invention
Portland cement is a hydraulic binder that is most commonly used in construction. Portland cement mainly includes a mixture of calcium silicate and calcium aluminate minerals that can react with water forming a dense, solid paste. However, Portland cement has some drawbacks when used as a binder for concretes. Materials using Portland cement can be degraded by sulphate attack from seawater or drainage water. Steel used in reinforced Portland concrete is corrosive when pH in the system is under a certain level. Some aggregates can cause alkali-silica reactions in the materials using high alkali Portland cement resulting in cracks and degradation. In addition, Portland cement has higher heat of hydration than other cement types, and therefore it is not suitable for use in some environments. For example, high heat of hydration can cause cracking when Portland cement is used in hot climates.
Fly ash is a by-product obtained from coal-burning thermal power plant. Fly ash contains mainly glassy, amorphous components including alumina and silica. ASTM C 618-00 has classified fly ash into two classes: Class C and Class F, depending on the total amount of calcium oxide, silica, alumina and ferric oxide content present. Class F contains more than 70% of the above mentioned oxides , but less than 20% lime (CaO). Class C contains less than 70%, but more than 50% of the abovementioned compounds. Class C fly ash generally contains more than 20% lime (CaO). Class F fly ash has pozzolanic properties, which means that
it can react with calcium hydroxide in the presence of water to make calcium aluminate and calcium silicate hydrates. Class C fly ash, in addition to having pozzolanic properties, also has hydraulic properties.
Replacing one part of Portland cement by fly ash in cement and concrete productions brings some advantages to environment, technology and economy. Using fly ash reduces exploitation of natural recourses for Portland cement production such as limestone, clay and consumes industrial by-product. That helps to decrease the amount of CO2 emitting and fuel burnt during cement production. Those contribute to the protection of the environment and lower the price of the cementitious binder used for concrete production. Concrete comprising fly ash has improved workability, lower risks of thermal cracking and decreased damages caused by alkali-silica reactions in the system using high alkali Portland cement. However, fly ash has one main drawback originating from its slow pozzolanic reaction in early ages. This slow reaction, particularly at low temperature, results in low early compressive strength that causes the extension of operating time at the jobsite and delays the applications of concrete using this kind of binder into service. It is generally accepted that the amount of Portland cement replaced by fly ash should not exceed about 20% to avoid a significant reduction in early compressive strength. That means the amount of fly ash used in concrete industry is still limited.
The early compressive strength of hydraulic binders containing Portland cement and fly ash, particularly at high level of Portland replacement can be increased by applying some alkali compounds such as alkali metal hydroxides, alkali sulphate salts, etc to increase the alkalinity of the system. The increase in alkalinity helps to activate the pozzolanic reaction of fly ash due to the increased solubility of fly ash in high pH environment (pH > 13). However, the amount of solid alkali substances required to be added into the system to cause a significant accelerating effect is quite high and this will expense the final strength and long term durability of material using this kind of binder.
The prior art also focuses on using chemicals to shorten the setting time to reduce the working time on the construction site and increase the circulation of the forms and moulds. KR 200801 1 1645 A describes an accelerator for increasing the fly ash mixing ratio in concrete, comprising polycarboxylic acid salt, triethanol-
amine, sodium thiocyanate, glycine, nitrate and water. KR 20060018594 A describes non-alkaline accelerators for concrete admixtures. US 2004/0244655 A1 relates to an accelerator used for setting and hardening of hydraulic binders. The main components of the accelerator are nitrates, aminoalcohols, hydroxyl- carboxylic acids and polyalcohols. US 5605571 A discloses an accelerator used for setting and hardening of hydraulic binders containing at least a nitrate- or sulfite component, at least a thiocyanate component, at least an alkanolamine component and at least a carboxylic acid component.
There is a demand to develop a new hardening accelerator for hydraulic binders composing of Portland cement and fly ash with high level of Portland cement replacement at both low and normal temperatures. The new accelerator should contain no chloride and sharply diminish the drawbacks caused by adding high dosages of chemical into binder systems.
Summary of the invention
The composition of the new accelerator admixture of the present invention includes: at least one inorganic thiocyanate, at least one organic alkanolamine, at least one organic polyol, and optionally water. All these compounds are known individually producing an accelerating effect on hydration of hydraulic binders, but it has been surprisingly found a synergistic effect when they are combined in the proportion of the present invention.
The accelerator according to the invention contains no chloride. The accelerator according to the invention is suitable for accelerating the hardening of hydraulic binders, particularly for binders comprising of Portland cement and fly ash with high proportions of fly ash. The accelerator is suitable for manufacturing prefabricated concretes or for accelerating the hardening of concrete produced on the construction site.
The components of the accelerator according to the invention can be combined and then added together to other ingredients (binders, aggregates, fillers) to make concrete or they can be added separately. The accelerator can also be added to mixing water before being added to the mixture of binders and other ingredients.
Figures
Figure 1 : Diagram showing rate of heat of hydration in OPC samples with combinations of the components and components individually and sample with no admixture.
Figure 2: Diagram showing rate of heat of hydration in OPC samples using 2- and 3-component admixture and with no admixture.
Figure 3: Diagram showing rate of heat of hydration in OPC (70%) and FA (30%) samples to combinations of the components and components individually and sample with no admixture.
Detailed Description of the Invention
The accelerator according to the invention comprises at least one inorganic thiocyanate, at least one organic alkanolamine, at least one organic polyol and optionally water.
A preferred thiocyanate is an alkaline thiocyanate, alkaline earth
thiocyanate or mixtures thereof. A preferred example is sodium thiocyanate.
A preferred alkanolamine is mono-, di-, triethanolamine, triisopropanol- amine, or mixtures thereof. Diethanolamine is especially preferred.
A preferred polyol is a lower alcohol with carbon chain from C2 to C6, or mixtures thereof. 1 ,2,3-propanetriol (glycerol) is especially preferred.
The accelerator according to the invention contains from 5 to 50 % by weight of the at least one inorganic thiocyanate, from 1 to 20% by weight of the at least one organic alkanolamine, from 1 to 20 % by weight of the at least one polyol, and any remainder being water. Preferably, the accelerator according to the invention comprises from 10 to 40 % by weight of the at least one inorganic thiocyanate, from 5 to 15 % by weight of the at least one organic alkanolamine, from 5 to 20 % by weight of the at least one polyol , and any remainder being water.
The accelerator according to the invention is suitable for accelerating the hardening of hydraulic binders, particularly for binders comprising of Portland cement and fly ash with high proportions of fly ash (>20 % by weight). The accelerator is appropriate for manufacturing prefabricated concretes or for accelerating the hardening of concrete produced on the construction site.
The proportion of fly ash in hydraulic binders can be more than 20 % by weight relative to the total weight of the hydraulic binders.
The accelerator can be added to hydraulic binders, particularly binders comprising Portland cement and fly ash, in the dosages of from 0.5 to 5 % by weight based on the total weight of the hydraulic binders, more preferably in the dosages of from 1 to 3 % by weight.
The components of the accelerator according to the invention can be combined in dispersed form in water and then added together to other ingredients (binders, aggregates, fillers) to make concrete or they can be added separately.
Examples
The following examples are given to demonstrate the effects of the accelerator according to the invention at low temperature (5°C) and normal temperatures (20°C).
The accelerator according to the invention that was used in the following test mixtures has a composition as disclosed in Table 1 .
Table 1
EXAMPLE 1 :
The effects of the accelerator on the hardening of mortar were tested. The compressive strength was tested with samples of mortar 4x4x16 cm size. The compositions of mortars are made up as disclosed in Table 2.
Table 2
Table 3 shows the effect of the accelerator on the hardening of mortars at 5°C after ageing 2 days and 28 days.
Table 3
Table 4 shows the effect of the accelerator on the hardening of mortars at 20°C after ageing 1 day and 28 days.
Table 4
EXAMPLE 2
The effects of the accelerator on the hardening of concrete were tested. The concrete samples with size of 10x10x10 cm were made for compressive strength test with compositions as disclosed in Table 5:
Table 5
Table 6 shows the effect of the accelerator on the hardening of concretes at 5°C after ageing 2 days and 28 days.
Table 6
Table 7 shows the effect of the accelerator on the hardening of concretes at 20°C after ageing 18 hours, 2 days and 28 days.
Table 7
EXAMPLE 3
The effects of the accelerator on the hardening of concrete with CEM ll/A-V (cement containing minimum 20% FA) were also tested. The concrete samples
with size of 10x10x10 cm were made for compressive strength test with
compositions as disclosed in Table 8:
Table 8
Table 9 shows the effect of the accelerator on the hardening of concretes at 5°C after ageing 2 days and 28 days.
Table 9
Table 10 shows the effect of the accelerator on the hardening of concretes at 20°C after ageing 18 hours, 2 days and 28 days.
Table 10
Compressive strength (MPa)
Mixture
18 hours 1 day 28 days
E (without 9.0
19.3 53.0
accelerator)
F (with accelerator) 17.1 21 .7 54.0
EXAMPLE 4
The effects of the accelerator on the hardening of concrete with CEM I (containing no fly ash) were also tested. The concrete samples with size of 10x10x10 cm were made for compressive strength test with compositions as disclosed in Table 1 1 :
Table 1 1
Table 12 shows the effect of the accelerator on the hardening of concretes at 5°C after ageing 2 days and 28 days.
Table 12
Table 13 shows the effect of the accelerator on the hardening of concretes at 20°C after ageing 18 hours, 2 days and 28 days.
Table 13
Compressive strength (MPa)
Mixture
18 hours 1 day 28 days
G (without
24.8 32.5 60.0
accelerator)
H (with accelerator) 30.5 35.1 63.3
To conclude the accelerator effect in mixtures A-H, the relative increased compressive strength is shown in Table 14.
Table 14
The accelerator has strongest effect at early age or at low temperature. EXAMPLE 5
The heat development cement added the accelerator components combined / not combined are presented in the Tables 15 and 16 below and in Figures 1 to 3.
The binder pastes contained Portland cement CEM I (OPC) and fly ash io class F (FA) with added water water/binder = 0.4. The paste parallels had no admixture (control) and with added NaSCN, DEA, and Glycerol to the water individually with dosages of 0.2%, 0.1 % respectively as well as with the 3- component admixture composed of (0.2% NaSCN + 0.1 % DEA + 0.05% Gly). i s Table 15: The cumulative heat and maximum rate of heat evolution effect of admixture in OPC.
* A¾2^C>H
Table 16: The cumulative heat and maximum rate of heat evolution effect of admixture in OPC (70%) and FA (30%).
Tables 15 and 16 show that the heat evolutions from the combination of the components are higher than the heat evolutions from the individual components. This synergistic effect is found in Portland cement CEM I and also when 30% of OPC is replaced with fly ash.
Figures 1 and 3 show how the combination of components affects the heat as function of time. This synergistic effect is clearly shown for the combination of the 3 components admixture in Figure 2.
Claims
1 . An accelerator for hardening of hydraulic binders, characterized in that it comprises the following components:
at least one inorganic thiocyanate,
at least one organic alkanolamine,
at least one organic polyol, and
optionally water.
2. The accelerator as claimed in claim 1 , in which the at least one inorganic thiocyanate is selected from the group of alkaline thiocyanate, alkaline earth thiocyanate or mixtures thereof.
3. The accelerator as claimed in claim 2, in which the at least one thiocyanate is sodium thiocyanate.
4. The accelerator as claimed in any of claims 1 to 3, in which the at least one organic alkanolamine is selected from the group of mono-, di-, triethanolamines and triisopropanolamine or mixtures thereof.
5. The accelerator as claimed in claim 4, in which the at least one alkanolamine is diethanolamine.
6. The accelerator as claimed in any of claims 1 to 5, in which the at least one organic polyol is selected from the group of C2-C6 polyols or mixtures thereof.
7. The accelerator as claimed in claim 6, in which the polyol is 1 ,2,3-propanetriol .
8. The accelerator as claimed in any of claims 1 to 7, in which the accelerator contains from 5 to 50 % by weight of the at least one inorganic thiocyanate, from 1 to 20% by weight of the at least one organic alkanolamine, from 1 to 20 % by weight of the at least one polyol, and any remainder being water.
9. A composition for producing mortar or concrete comprising hydraulic binder, sand and water, characterized in that the composition further comprises the accelerator according to claims 1 to 8.
10. The composition as claimed in claim 9, wherein the hydraulic binder comprises a mixture of Portland cement and fly ash, wherein the content of fly ash is more than 20 % by weight relative to the total weight of the hydraulic binders.
1 1 . The composition according to claims 9 or 10, comprising the accelerators, in dosages of 0.5 to 5 % by weight based on the total weight of the hydraulic binders.
12. A method of accelerating the setting and hardening of a hydraulic binder, or of mortars or concrete produced therefrom, wherein the accelerator as claimed in claims 1 to 8 is added in dosages of from 0.5 to 5 % by weight to the hydraulic binder.
13. The method as claimed in claim 12, wherein the accelerator is dispersed in water and subsequently added to a mixture of binders and other ingredients to make concrete.
14. Use of the accelerator of claims 1 to 8 for accelerating the hardening of hydraulic binders, particularly for binders comprising Portland cement and fly ash with proportions of fly ash > 20%.
15. Use according to claim 14 for manufacturing prefabricated concretes or for accelerating the hardening of concrete produced on the construction site.
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NO20111524 | 2011-11-04 | ||
NO20111524A NO20111524A1 (en) | 2011-11-04 | 2011-11-04 | Curing accelerator and a method for accelerating the curing of hydraulic binders and mixtures thereof |
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Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2015161672A (en) * | 2014-02-28 | 2015-09-07 | 清水建設株式会社 | Determination method and determination device for admixture in cement |
EP3109216A1 (en) | 2015-06-22 | 2016-12-28 | HeidelbergCement AG | Hardening and setting accelerator for hydraulic binding agents |
JP2017537053A (en) * | 2014-11-04 | 2017-12-14 | エスエムテク カンパニー リミテッドSmtech Co., Ltd | Cement-free admixture and cement-free composition containing the same |
EP3438073A1 (en) * | 2017-07-31 | 2019-02-06 | Chryso | Additive for hydraulic binder useful to prevent the formation of rust-colored stains at the surface of hydraulic compositions |
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KR20060018594A (en) | 2004-08-25 | 2006-03-02 | 요업기술원 | Process of producing non-alkaline accelerators admixtures for concrete complex |
CN101289293A (en) * | 2008-06-13 | 2008-10-22 | 北京工业大学 | Polycarboxylic acids anti-freeze agent for cement concrete and method for preparing same |
KR20080111645A (en) | 2007-06-19 | 2008-12-24 | 주식회사 실크로드시앤티 | Accelerating admixture compositions for increasing fly ash mixing ratios in winter season |
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US5605571A (en) | 1994-03-03 | 1997-02-25 | Sika Ag, Vorm. Kaspar Winkler & Co. | Setting- and hardening-accelerator containing no chloride and nitrite and a method to accelerate the setting and hardening of hydraulic binders and mixtures thereof |
US20040244655A1 (en) | 2001-06-22 | 2004-12-09 | Christian Buerge | Method for accelerating the setting and hardening of hydraulic binding agents and mixtures containing the same |
KR20060018594A (en) | 2004-08-25 | 2006-03-02 | 요업기술원 | Process of producing non-alkaline accelerators admixtures for concrete complex |
KR20080111645A (en) | 2007-06-19 | 2008-12-24 | 주식회사 실크로드시앤티 | Accelerating admixture compositions for increasing fly ash mixing ratios in winter season |
CN101289293A (en) * | 2008-06-13 | 2008-10-22 | 北京工业大学 | Polycarboxylic acids anti-freeze agent for cement concrete and method for preparing same |
Cited By (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2015161672A (en) * | 2014-02-28 | 2015-09-07 | 清水建設株式会社 | Determination method and determination device for admixture in cement |
JP2017537053A (en) * | 2014-11-04 | 2017-12-14 | エスエムテク カンパニー リミテッドSmtech Co., Ltd | Cement-free admixture and cement-free composition containing the same |
EP3109216A1 (en) | 2015-06-22 | 2016-12-28 | HeidelbergCement AG | Hardening and setting accelerator for hydraulic binding agents |
WO2016206780A1 (en) | 2015-06-22 | 2016-12-29 | Heidelbergcement Ag | Solidification and hardening accelerator for hydraulic binders |
EP3438073A1 (en) * | 2017-07-31 | 2019-02-06 | Chryso | Additive for hydraulic binder useful to prevent the formation of rust-colored stains at the surface of hydraulic compositions |
US11560337B2 (en) | 2017-07-31 | 2023-01-24 | Chryso | Additive for hydraulic binder useful to prevent the formation of rust-colored stains at the surface of hydraulic compositions |
Also Published As
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