Solidification and hardening accelerator for hydraulic binding agents and method for the production thereof
US20060236895A1
2006-10-26
10/532,791
2003-11-11
Abstract:
A setting and curing accelerator for hydraulic binders comprises: Al2(SO4)3 aluminum sulfate, Al(OH)3 aluminum hydroxide and mineral acid in aqueous solution. The setting and curing accelerator preferably comprises:
-
- 10-50% of Al2(SO4)3 aluminum sulfate,
- 5-30% of Al(OH)3 aluminum hydroxide, 0.5-10% of a mineral acid in aqueous solution.
Inventors:
- Urs MADER 13 🇨🇭 Frauenfeld, Switzerland
- Benedikt Lindlar 8 🇩🇪 Konstanz, Germany
- Franz Wombacher 6 🇨🇭 Oberlunkhofen, Switzerland
- Marcel Sommer 2 🇨🇭 Pfungen, Switzerland
Assignee:
- SIKA TECHNOLOGY AG 1,037 🇨🇭 Baar, Switzerland
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Classification:
C04B2111/00155 » CPC further
Mortars, concrete or artificial stone or mixtures to prepare them, characterised by specific function, property or use; Physico-chemical characteristics of the mixtures; Sprayable or pumpable mixtures Sprayable, i.e. concrete-like, materials able to be shaped by spraying instead of by casting, e.g. gunite
Y02E60/32 » CPC further
Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation; Hydrogen technology Hydrogen storage
Y02E60/32 » CPC further
Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation; Hydrogen technology Hydrogen storage
C04B28/02 » CPC further
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
C04B2103/10 » CPC further
Function or property of ingredients for mortars, concrete or artificial stone Accelerators; Activators
C04B22/165 » CPC further
Use of inorganic materials as active ingredients for mortars, concrete or artificial stone, e.g. accelerators, shrinkage compensating agents; Acids or salts thereof containing phosphorus in the anion, e.g. phosphates Acids
C04B22/0013 » CPC further
Use of inorganic materials as active ingredients for mortars, concrete or artificial stone, e.g. accelerators, shrinkage compensating agents Boron compounds
C04B40/0039 » CPC main
Processes, in general, for influencing or modifying the properties of mortars, concrete or artificial stone compositions, e.g. their setting or hardening ability; Aspects relating to the mixing step of the mortar preparation Premixtures of ingredients
C04B14/062 » CPC further
Use of inorganic materials as fillers, e.g. pigments, for mortars, concrete or artificial stone; Treatment of inorganic materials specially adapted to enhance their filling properties in mortars, concrete or artificial stone; Granular materials, e.g. microballoons; Silica-rich materials; Silicates; Quartz; Sand Microsilica, e.g. colloïdal silica
C04B14/303 » CPC further
Use of inorganic materials as fillers, e.g. pigments, for mortars, concrete or artificial stone; Treatment of inorganic materials specially adapted to enhance their filling properties in mortars, concrete or artificial stone; Granular materials, e.g. microballoons; Oxides other than silica Alumina
C04B22/082 » CPC further
Use of inorganic materials as active ingredients for mortars, concrete or artificial stone, e.g. accelerators, shrinkage compensating agents; Acids or salts thereof Acids
C04B22/148 » CPC further
Use of inorganic materials as active ingredients for mortars, concrete or artificial stone, e.g. accelerators, shrinkage compensating agents; Acids or salts thereof containing sulfur in the anion, e.g. sulfides; Sulfates Aluminium-sulfate
C04B24/122 » CPC further
Use of organic materials as active ingredients for mortars, concrete or artificial stone, e.g. plasticisers; Nitrogen containing compounds organic derivatives of hydrazine Hydroxy amines
C04B24/2641 » CPC further
Use of organic materials as active ingredients for mortars, concrete or artificial stone, e.g. plasticisers; Macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds Polyacrylates; Polymethacrylates
C04B28/26 IPC
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 alkyl, ammonium or metal silicates; containing silica sols Silicates of the alkali metals
C04B7/00 IPC
Cements
C04B7/00 IPC
Hydraulic cements
C04B40/00 IPC
Processes, in general, for influencing or modifying the properties of mortars, concrete or artificial stone compositions, e.g. their setting or hardening ability
Description
TECHNICAL FIELDThe invention relates to a setting and curing accelerator for hydraulic binders according to the preamble of the first claim.
The invention likewise relates to a process for producing a setting and curing accelerator for hydraulic binders according to the preamble of the independent process claim.
PRIOR ARTMany substances which accelerate the setting and curing of concrete are known. Customary substances are, for example, strongly alkaline substances such as alkali metal hydroxides, alkali metal carbonates, alkali metal silicates, alkali metal aluminates and alkaline earth metal chlorides. However, the strongly alkaline substances have undesirable effects on the processor, e.g. burns, and they reduce the final strength and durability of the concrete.
EP 0 076 927 B1 discloses alkali-free setting accelerators for hydraulic binders which are said to avoid these disadvantages. To accelerate the setting and curing of a hydraulic binder such as cement, lime, hydraulic lime and plaster of Paris and mortar and concrete produced therefrom, from 0.5 to 10% by weight, based on the weight of this binder, of an alkali-free setting and curing accelerator comprising aluminum hydroxide is added to the mixture comprising the binder mentioned.
Such mortars and concretes are particularly well-suited as spray mortar and concrete as a result of the accelerated setting and curing.
EP 0 946 451 B1 discloses setting and curing accelerators in dissolved form for hydraulic binders, which can be more easily mixed into the concrete when spraying the concrete. Such a setting and curing accelerator comprises, inter alia, aluminum hydroxide, aluminum salts and organic carboxylic acids. However, a disadvantage of such setting and curing accelerators is the stability of the solution.
SUMMARY OF THE INVENTIONIt is an object of the invention to achieve a very high accelerating action combined with a very long life of the accelerator for a setting and curing accelerator for hydraulic binders of the type mentioned at the outset.
According to the invention, this is achieved by the features of the first claim.
The advantages of the invention are, inter alia, that a high stability, i.e. stabilization of the accelerator solution, is achieved by means of the accelerators of the invention and that high acceleration of the setting and curing of hydraulic binders is achieved.
Hydraulic binders with addition of the accelerator of the invention can be processed advantageously by spraying because of their accelerated setting and curing behavior.
Further advantageous embodiments of the invention are disclosed in the subordinate claims.
WAY OF CARRYING OUT THE INVENTIONA setting and curing accelerator according to the invention for hydraulic binders comprises:
Al2(SO4)3 aluminum sulfate, Al(OH)3 aluminum hydroxide and mineral acid in aqueous solution.
Such a setting and curing accelerator according to the invention advantageously consists essentially of (in % by weight):
10-50% of Al2(SO4)3 aluminum sulfate,
5-30% of Al(OH)3 aluminum hydroxide,
0.5-10% of mineral acid,
0-10% of alkanolamine,
0-5.0% of fluidizer,
0-20% of stabilizer,
in aqueous solution.
As mineral acid, preference is given to using phosphoric or boric acid, but it is also possible to use other mineral acids having a similar action, e.g. nitric acid, sulfuric acid, etc.
Diethanolamine is advantageously used as alkanolamine. Polycarboxylates, particularly advantageously Sika ViscoCrete®, in particular Sika ViscoCrete® 20HE are advantageously used as fluidizers.
Silica sol is advantageously used as stabilizer.
Particularly advantageous setting and curing accelerators consist essentially of (in % by weight):
30-50% of Al2(SO4)3 aluminum sulfate, in particular 40-45%, and/or
5-20% of Al(OH)3 aluminum hydroxide, in particular 10-17%, and/or
0.5-8% of mineral acid and/or
0-5% of alkanolamine and/or
0.1-3.0% of fluidizer, in particular from 0.1 to 1.0%, and/or
0-10% of stabilizer.
It is also advantageous to add the mineral acid fraction of 0.5-10% as H3PO4 phosphoric acid and/or H3BO3 boric acid. Particularly advantageous ranges are 1-5% of H3PO4 phosphoric acid and/or 0.5-3.0% of H3BO3 boric acid.
A number of samples of an accelerator according to the invention were produced in the above-described ranges. The composition of these samples is indicated in the following examples.
EXAMPLE 17.60 kg of aluminum hydroxide Al(OH)3 are added to a solution of 22.50 kg of aluminum sulfate with water of crystallization Al2(SO4)3×14H2O in 17.06 kg of water H2O at 70-80° C. 1.14 kg of a phosphoric acid solution H3PO4 (75%), 2 kg of a silica sol (10% solids content) and 1.70 kg of a corrosion inhibitor, viz. a 90% solution of diethanolamine, are subsequently added to the resulting solution and this mixture is stirred for half an hour.
The stability of this mixture was at least 70 days.
EXAMPLE 27.60 kg of aluminum hydroxide Al (OH)3 are added to a solution of 22.50 kg of aluminum sulfate with water of crystallization Al2(SO4)3×14H2O in 14.86 kg of water H2O at 70-80° C. 2.84 kg of a phosphoric acid solution H3PO4 (75%), 0.50 kg of polycarboxylates, e.g. Sika ViscoCrete® 20HE which is a high-performance fluidizer, and 1.70 kg of a corrosion inhibitor, viz. a 90% solution of diethanolamine, are subsequently added to the solution obtained and this mixture is stirred for half an hour.
The stability of this mixture was at least 70 days.
EXAMPLE 38.00 kg of aluminum hydroxide Al(OH)3 are added to a solution of 22.50 kg of aluminum sulfate with water of crystallization Al2(SO4)3×14H2O in 16.56 kg of water H2O at 70-80° C. 1.14 kg of a phosphoric acid solution H3PO4 (75%), 0.10 kg of boric acid H3BO3 and 1.70 kg of a corrosion inhibitor, viz. a 90% solution of diethanolamine, are subsequently added to the solution obtained and this mixture is stirred for half an hour. The stability of this mixture was at least 70 days.
EXAMPLE 48.10 kg of aluminum hydroxide Al(OH)3 are added to a solution of 20.60 kg of aluminum sulfate with water of crystallization Al2(SO4)3×14H2O in 21.00 kg of water H2O at 70-80° C. 0.30 kg of boric acid H3BO3 is subsequently added to the resulting solution and this mixture is stirred for half an hour.
The stability of this mixture was at least 70 days.
EXAMPLE 58.00 kg of aluminum hydroxide Al(OH)3 are added to a solution of 21.00 kg of aluminum sulfate with water of crystallization Al2(SO4)3×14H2O in 20.00 kg of water H2O at 70-80° C. 1.00 kg of boric acid H3BO3 and 0.50 kg of polycarboxylates, e.g. Sika ViscoCrete® 20HE which is a high-performance fluidizer, are subsequently added to the solution obtained and this mixture is stirred for half an hour.
The stability of this mixture was at least 70 days.
From 0.1 to 10% by weight of the accelerator of the invention can be added to the hydraulic binder.
To determine the effectiveness of the accelerator of the invention from Examples 1 to 5, 6% of the accelerator from the above examples was in each case mixed into portland cement and penetrometer values were determined. The following table shows the penetrometer values together with the time required in each case to reach strengths of 200 g, 600 g and 2200 g. These penetrometer values were determined using a needle having a diameter of 3 mm and a test apparatus from RMU.
A sample of portland cement without accelerator was used as comparison and the penetrometer values for the same sample composition when the accelerator was left out without replacement and when the accelerator was replaced by a corresponding amount of water were determined.
| Penetrometer value for |
| 200 g | 600 g | 2200 g | |
| Example 1 | 5 | min | 7 | min | 15 | min |
| Example 2 | 6 | min | 8 | min | 16 | min |
| Example 3 | 6 | min | 9 | min | 20 | min |
| Example 4 | 7 | min | 14 | min | 40 | min |
| Example 5 | 12 | min | 20 | min | 55 | min |
| Sample without accelerator | 450 | min | 485 | min | 540 | min |
| Sample without accelerator | 490 | min | 522 | min | 579 | min |
| but with equivalent amount | ||||||
| of water | ||||||
The accelerators prepared as described in Examples 1 to 5 thus gave solutions which display satisfactory acceleration values and remain stable for a sufficiently long time.
The accelerators of the invention can also be used for hydraulic binders other than cement, e.g. blended cements, lime, hydraulic lime and plaster of Paris and also mortar and concrete produced therefrom.
Of course, the invention is not restricted to the example presented and described. The accelerators present in aqueous solution can also be used in dried form, e.g. after drying by means of a generally known spray drying process. The dried powder obtained in this way, which is readily soluble in water, is dissolved in water before use and then used in the same way as the liquid accelerator. The samples prepared as described in Examples 1 to 5 can also be produced in a temperature range from room temperature RT to 90° C., but preferably in a range from 50 to 80° C.
Claims
1. A setting and curing accelerator for hydraulic binders, comprising:
Al2(SO4)3 aluminum sulfate, Al(OH)3 aluminum hydroxide and mineral acid in aqueous solution.
2. The setting and curing accelerator as claimed in claim 1,
characterized in that (in % by weight) the proportion of aluminum sulfate is 10-50% and/or the proportion of aluminum hydroxide is 5-30% and/or the proportion of mineral acid is 0.5-10%.
3. The setting and curing accelerator as claimed in claim 1, characterized in that (in % by weight) the proportion of aluminum sulfate is 30-50% and/or the proportion of aluminum hydroxide is 5-20%.
4. The setting and curing accelerator as claimed in claim 1, characterized in that (in % by weight) the proportion of aluminum sulfate is 40-45% and/or the proportion of aluminum hydroxide is 10-17% and/or the proportion of mineral acid is 0.5-8%.
5. The setting and curing accelerator as claimed in claim 1,
characterized in that the mineral acid present comprises (in % by weight) 1-5% of H3PO4 phosphoric acid and/or 0.5-3.0% of H3BO3 boric acid.
6. The setting and curing accelerator as claimed in claim 1,
characterized in that (in % by weight) 0-10% of alkanolamine and/or 0-5.0% of fluidizer and/or 0-20% of stabilizer are present.
7. The setting and curing accelerator as claimed in claim 1,
characterized in that (in % by weight) 0-5% of alkanolamine and/or 0-10% of stabilizer and/or 0-3.0% of fluidizer are present.
8. The setting and curing accelerator as claimed in claim 6, characterized in that the alkanolamine is a diethanolamine.
9. The setting and curing accelerator as claimed in claim 6, characterized in that the stabilizer is a silica sol.
10. The setting and curing accelerator as claimed in claim 6, characterized in that the fluidizer is a polycarboxylate.
11. A process for producing a setting and curing accelerator, characterized in that a setting and curing accelerator as claimed in claim 1 which is present in aqueous solution is dried, in particular by a spray drying process.
12. The process for producing a setting and curing accelerator as claimed in claim 11,
characterized in that the dried mixture obtained is dissolved in water before addition to the hydraulic binder.
13. A process for producing a setting and curing accelerator as claimed in any of claim 1,
characterized in that in the production of the aqueous solution and the addition of the components in the production of the solution, the solution is heated in a range from room temperature to 90° C.
14. The process for producing a setting and curing accelerator as claimed in claim 13,
characterized in that the solution is heated to 50-80° C.
15. A method of accelerating the setting and curing of hydraulic binders and also mortar or concrete produced therefrom,
characterized in that a setting and curing accelerator as claimed in claim 1 is added in an amount of from 0.1 to 10% by weight to a mixture comprising hydraulic binders, with the percentages by weight being based on the weight of the hydraulic binder.
16. The use of the setting and curing accelerator as claimed in claim 1 in a spray concrete or spray mortar.