AU783765B2 - Stabilized setting and hardening accelerator of low viscosity - Google Patents

Description

AUSTRALIA

PATENTS ACT 1990 COMPLETE SPECIFICATION NAME OF APPLICANT(S): k ch Sikar AG o_ Kapar Winiler Co.

ADDRESS FOR SERVICE: DAVIES COLLISON CAVE Patent Attorneys 1 Little Collins Street, Melbourne, 3000.

INVENTION TITLE: Stabilized setting and hardening accelerator of low viscosity The following statement is a full description of this invention, including the best method of performing it known to me/us:- TECHNICAL FIELD The present invention concerns a stabilized accelerator of low viscosity for the setting and i0 hardening of a hydraulic binder, its use and a method for setting hydraulic binders using said accelerator.

BACKGROUND ART 1 :.Many substances that accelerate the setting and hardening of concrete are already known. The most usual are i.e. strongly alkaline reacting substances such as alkali hydroxides, alkali carbonates, alkali silicates, alkali aluminates and alkaline earth chlorides. With strongly alkaline reacting substances undesired annoyance of the user occurs. Such products may cauterize the skin and cause inflammation of the eye or they may cauterize the cornea thereby affecting the 25 strength of vision. Due to inhalation of the dust or aerosol generated during use, furthermore detrimental effects on the respiratory system may develop.

In view of concrete technology, very alkaline setting accelerators reduce the final strength and enhance the shrinkage, what may cause crack formation and therefore may reduce the long lasting properties, in particular the resistance to sulfates of such concrete.

Besides of the above-mentioned strongly..

alkaline accelerators also already other accelerators have been described.

Accelerators for the setting of hydraulic binders on the basis of amorphous aluminum hydroxide are laalready known from EP-A 0 026 262, in particular claims 1 and 11 to 13, as well as from Chemical Abstracts Vol. 86, No. 18, May 1977, page 300, 126087c.

According to EP-A 0 026 262, page 2, last paragraph, the particle size of the amorphous aluminum hydroxide is in particular in the range between 4.8 and 5.4 pm.

In such hardening accelerators also cellulose products that are able the swell and further admixtures may be present, see EP-A 0 026 262, in particular claims 8 to 10 and the examples.

From DE-A 2 548 687, in particular claim and page 15, the addition of aluminum sulfate or nitrates to setting accelerators on the basis of aluminates and 15 aluminum oxide is known.

From FR-A 2 471 955, in particular claims 1 to 6, the use of formiates and nitrates in accelerators is known.

EP 0 076 927 describes a method for accelerating the setting by addition of amorphous aluminum hydroxide and at least one water-soluble sulfate and/or nitrate and/or formiate.

EP 181 739 Al describes the use of calcium sulfo- aluminate and a mixture of calcium aluminates that together with alkalis or earth alkalis upon addition of 250 water result in a hardenable slurry.

JP 63 206 341 A2 protects an accelerator of calcinated alunit, calcium sulfoaluminate, sodium aluminate, sodium carbonate.

JP 58 190 849 A2 describes a mixture of calcium sulfoaluminate, calcium sulfate hemihydrate and calcium hydroxide for the preparation of fast setting, sprayable coatings.

SU 697 427 mentions a fast setting concrete due to admixture of calcium aluminate, calcium sulfoaluminate, calcium oxide, ferrite, silicate and gypsum.

2 JP 54 027 817 mentions the accelerated hardening of gypsum by addition of calcium sulfoaluminate.

JP 53 099 228 describes an accelerator for casting mortar based on calcium sulfoaluminate and calcium fluoroaluminate and water reducing agents.

In DE-OS 2 163 604 accelerators based on calcium fluoroaluminate are mentioned.

From JP 01 290 543 A2 mixtures of calcium sulfo- aluminate and calcium sulfate and lithium carbonate are known as accelerator for low temperature application.

SU 1 350 135 Al discloses fast setting S. 15 clinker due to supplementation with barium sulfate, calcium aluminate and calcium sulfoaluminate.

WO 97/36839 discloses the use of lithium silicate and/or lithium aluminate and/or aluminum salts.

WO 98/18740 comprises a method for the 20 production of a setting and hardening accelerator for hydraulic binders. The product that according to claim 1 necessarily consists of 5 components is very turbid, has a high viscosity and a low storage stability. Said *."accelerator may lead to the plug up of the spray nozzle.

25 At the construction site, the high viscosity results in problems during the dosing of the product, in particular at low temperatures. A dilution of the product is not possible since thereby a part of the basic salts are precipitated. The low pH-value results in corrosion at the dosing and spraying devices.

The goal of the present invention was to provide a composition that acts as setting and hardening accelerator and that preferably is alkali-free and chloride-free and by which very fast setting can be achieved.

3 P OPER S1n38785-OI Ispl d.c-051=5 -4- BRIEF SUMMARY OF THE INVENTION The present invention provides a composition comprising at least one aluminum salt and furthermore a) at least one complexing agent for the aluminum ion and b) at least one corrosion inhibitor.

The present invention seeks to provide a stabilized composition of low viscosity suitable to act as accelerator for the setting and hardening of a binder or a binder comprising mixture.

The present invention further provides a method wherein 0.1 to 10 by weight referred to the weight of the binder of the composition according to the invention is added to said binder or binder comprising mixture.

Possibilities for the application of the composition according to the invention and the method according to the o invention is in the production of pre-casting elements and the acceleration of concrete produced at the construction site. In the first case, the heating (by means of electro heating, or oil heating, or steam), usually applied for accelerating the hardening, can be reduced or even eliminated. In the second case the demolding times of the concrete may be shortened, or the further application of concrete may be continued also at low temperatures. Further applications are in the production of fast setting cement S. 25 mixtures and mortar mixtures, in particular for fixing prefabricated units, castings etc.

A specific field of use is in particular spraying mortar and spraying concrete. Such mortar and concrete serve the production of buildings of underground and surface engineering as well as the completion and lining of underground, natural or technically produced cavities, such as pit constructions, tunnel constructions or mining constructions, for which the concrete must meet the static requirements as well as being water impermeable. They also serve the consolidation of trenches, slopes, loose walls of rock etc.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will be better understood and objects other than those set forth above will become apparent when consideration is given to the following dei0 tailed description thereof. Such description makes reference to the annexed drawing, wherein the viscosity development of different setting accelerators is shown.

15 DETAILED DESCRIPTION OF THE INVENTION The low viscosity stabilized accelerator for the setting and hardening of a hydraulic binder or hydraulic binder comprising mixtures is for example suitable for binders such as cement and hydraulic lime, each alone or in admixture with latent hydraulic binders and/or inert fillers and examples for mixtures comprising such binders are mortar and concrete.

Further aspects of the present invention are defined in further independent claims and preferred embodiments are the subject of dependent claims.

Particularly preferred accelerators according to the present invention are alkali-free and chloridefree. The aluminum salts are preferably selected from the group comprising or consisting of sulfate, nitrate, glycolate, lactate, acetate, formiate, hydroxy formiate, the respective basic salts of the sulfate, nitrate, glycolate, lactate, acetate, formiate, hydroxy formiate, or mixtures of such salts. Preferably, the accelerator has a pH-value between 2 and 5, said pH-value being generated by a stoichiometric access of acid, for example organic acid. If sulfates and/or nitrates are present, 5 then a molar ratio between sulfate and/or nitrate to organic acid of 0.1 to 10 is preferred. Preferred complexing agents are chosen from the group comprising nitrilotriacetic acid, ethylene diamine tetraacetic acid, gluconic acid, heptonic acid, phosphonic acid or mixtures thereof. Usually such a complexing agent is present in an amount of 0.1 to 5.0 by weight. Preferred corrosion inhibitors are chosen from the group comprising alkines butine diol propargyl alcohol 3-(methylamino)propylamine 3-(dimethylamino)propylamine S 15 3-(diethylamino)propylamine cyclohexylamine N-methylcyclohexylamine N-ethylcyclohexylamine 1-(dimethylamino)-2-propanol l-(ethylamino)-2-propanol 1-(cyclohexylamino)-2-propanol 3-amino-l-propanol 2-aminoethanol 2, 2'-iminodiethanol 2-(methylamino)ethanol 2-(dimethylamino)ethanol 2-(ethylamino)ethanol 2-(diethylamino)ethanol and mixtures thereof.

Usual amounts of such corrosion inhibitors are in the range of 0.1 to 10.0 by weight referred to the weight of the binder. Furthermore, the accelerator may comprise at least one thickening agent that preferably is selected from the group comprising or consisting of bentonite, bentones, fermented organic biopolymers, alginates, polyglycolethers, acrylate thickeners or urethane thickeners, organic carbonic 6 esters and mixtures thereof. The accelerators of the present invention are preferably used to accelerate the setting and hardening of hydraulic binders, hydraulic binders in admixture with latent hydraulic binders and/or inert fillers, in particular for the acceleration of the setting and hardening of mortar or concrete. Particularly preferred is the use of the inventive setting and hardening accelerators in spraying mortar or spraying concrete, whereby they can be processed in the dry spraying process as well as in the wet spraying process.

Thereby, the accelerator can be added to the dry binder, mortar or concrete or to binder, mortar or concrete admixed with water, by means of a liquid dosing apparatus. Said addition by means of a liquid dosing 15 apparatus may be performed directly into the mixture or into the mixing water in the conveyor hose, the prewetting nozzle or the spray nozzle.

For all these applications, the setting and hardening accelerator can be used as solution, preferably 20 with a dry content of 20-60 The setting and hardening accelerator having the inventive composition can also be present as powder, whereby in this case it is preferred that it is dissolved in water prior to its use, e.g. at the construction site. It has been found that such dissolving in water at the construction site only does not bear any disadvantage with regard to the setting and hardening characteristics, however, great advantages with regard to the transport are obtained since no water has to be transported, a fact that is very much desirable in ecologic as well as economic respects.

By the use of the setting and hardening accelerators of the present invention, a very fast setting of the respective binders, or the mixtures comprising such binders, is effected, and high initial and final strength is achieved. The setting and hardening accelerator neither to the user nor to the environment have a caustic or toxic effect. Furthermore, if compared 7 to the use of alkaline accelerators, a significant reduction in the setting time and a fast development of high compressive strength is achieved. In comparison with commercialized alkali-free accelerators solid precipitations of aluminum salts and thereby generated plugging up of spray nozzles are avoided and the corrosion at the spraying apparatuses is eliminated.

Simultaneously, the costs at the construction site can be reduced due to the improved efficiency and the lower maintenance requirements of the apparatuses as well as the reduced breakdown time compared to hitherto used alkali-free accelerators. Besides of the technical advantages also very great economic advantage result.

Since the setting accelerators of the present 15 invention do not need any alkali, neither the development of strength nor the shrinkage are affected.

The following examples shall further describe invention.

Examples Accelerator consisting of: eeoc.

No. Component by mass 1 Water 36.4 Aluminum dihydroxyformiate 21 Aluminum sulfate 14 H 2 0 42 EDTA (stabilizer) 0.1 Butine diol (corrosion inhibitor) No. Component by mass 2 Water 35.4 Aluminum dihydroxyformiate 19 Aluminum sulfate 14 H 2 0 EDTA (stabilizer) 0.1 Butine diol (corrosion inhibitor) 8 No. Component by mass 3 Water 43.4 Aluminum dihydroxyformiate 26 Aluminum sulfate 14 H 2 0 EDTA (stabilizer) 0.1 Butine diol (corrosion inhibitor) EDTA Ethylene diamine tetraacetate (complexing agent for aluminum ions) were compared in the following examples with a usual, commercially available alkali-free accelerator.

In the following examples the influence of the inventive setting accelerator to cementituous systems is shown. As mixtures for examination mortars were 0 chosen, that are intended to simulate concrete. Said mixtures are composed as follows: Portland cement type CEM I 42.5 250.00 g Sand 0-2.2 mm 750.00 g Water 122.50 g Super plastiziser on the basis of melamine 2.50 g The setting samples were examined with a penetrometer of the firm RMU (Italy). Begin of setting and end of setting were recorded at a penetration resistance of the 2 mm needle of 600 g or 2200 g, respectively.

From said mixtures prismatic samples in the dimension 4x4x16 cm were produced and stored at 20 0 C and relative humidity.

9 Example 1 a a This example shows the effect on the setting time of a setting accelerator of the present invention in comparison to a usual accelerator.

Accelerator Resistance to penetration 600 g 2200 g Accelerator according to 20 min. 50 min.

invention No. 1 Accelerator according to 17 min. 53 min.

invention No. 2 Accelerator according to 22 min. 47 min.

invention No. 3 Usual, commercially available 30 min. 65 min.

accelerator Accelerator 6 referred to the cement mixture 0 Example 2 In this example a comparison of the development of strength by means of the samples described at the beginning is shown. Presented are the compressive strength in MPa after 1 day, 7 days and 28 days (day d).

0 Accelerator id 7d 28d Accelerator according to invention No. 1 18 31 48 Accelerator according to invention No. 2 19 32 48 Accelerator according to invention No. 3 16 27 43 Usual, commercially available accelerator 16 30 a.

•6 a a 10 Example 3 In this example the significantly improved or lower viscosity, respectively, of the accelerator according to the invention compared with usual setting accelerators is shown. The viscosity was measured by means of the outflow time from a Ford cup 0 4 mm.

Accelerator Age of sample new 2 months Accelerator according to 16 18 invention No. 1 Accelerator according to 18 19 invention No. 2 Accelerator according to 16 23 invention No. 3 Usual, commercially available 22 32 accelerator 10 Outflow time sec.

Clearly recognizable is the lasting low value of the outflow time of the inventive accelerator compared to the almost twice as long time of the usual accelerator. The viscosity development is shown in Fig.

i.

Example 4 In order to reduce the corrosion of metallic parts of the pump, hose connecting pieces and spray nozzles, a corrosion inhibitor was added to the accelerator of the present invention. The time until the start of the corrosion could be enhanced from 3 days for the commercial accelerator to 9 days in the case of the inventive accelerators.

The measurement was made on polished normed steel platelets (3x3 cm) that were entirely covered with 11 setting accelerator diluted with water in a ratio of 1:10, and stored therein. The platelets were optically examined in one day intervals, leading to the abovementioned result.

While there are shown and described presently preferred embodiments of the invention, it is to be distinctly understood that the invention is not limited thereto but may be otherwise variously embodied and practiced within the scope of the following claims.

Throughout this specification and the claims which follow, unless the context requires otherwise, the word "comprise", and variations such as "comprises" and "comprising", will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps.

S. The reference to any prior art in this specification is not, and should not be taken as, an acknowledgement or any form of suggestion that that prior art forms part of the common general knowledge in Australia.

oooo@ o*o* o* 12

Claims (16)

1. A composition comprising at least one aluminum salt and furthermore a) at least one complexing agent for the aluminum ion and b) at least one corrosion inhibitor.

2. The composition of claim 1 which is alkali-free and chloride-free.

3. The composition of claim 1 or 2 wherein the aluminum salt is selected from the group comprising sulfate, nitrate, glycolate, lactate, acetate, formiate, hydroxyformiate, the respective basic salts of the sulfate, nitrate, glycolate, lactate, acetate, formiate, hydroxyformiate, and mixtures of such salts. *o

4. The composition of any one of the preceding claims that comprises an acid in an amount corresponding to a stoichiometric excess of acid such that the pH-value is between 2 and The composition of claim 4 wherein said acid is an organic acid. o 6. The composition of claim 5 wherein the molar ratio of sulfate and/or nitrate to organic acid is from 0.1 to

7. The composition of any one of the preceding claims wherein the complexing agent is selected from the group consisting of nitrilotriacetic acid, ethylene diamine tetraacetic acid, gluconic acid, heptonic acid, phosphonic acid and mixtures thereof. P:\OPERSan3878OI Ipa doc-OI5/10 -14-

8. The composition of any one of the preceding claims wherein the complexing agent is comprised in an amount of from 0.1 to 5.0 by weight.

9. The composition of any one of the preceding claims wherein the corrosion inhibitor is selected from the group comprising alkines butine diol propargyl alcohol 3-(methylamino)propylamine 3-(dimethylamino)propylamine 3-(diethylamino)propylamine cyclohexylamine N-methylcyclohexylamine N-ethylcyclohexylamine 1-(dimethylamino)-2-propanol 1-(ethylamino)-2-propanol 1-(cyclohexylamino)-2-propanol 3-amino-l-propanol 9999 2-aminoethanol 2, 2' -iminodiethanol S2-(methylamino)ethanol 2-(dimethylamino)ethanol 2-(ethylamino)ethanol 2-(diethylamino)ethanol and mixtures thereof. The composition of any one of the preceding claims wherein the corrosion inhibitor is comprised in an amount of from 0.1 to 10.0 by weight. P.OPERIS.n\8785-) Ispa doc-O5/IO1

11. The composition of any one of the preceding claims that comprises at least one thickening agent.

12. The composition of claim 11 wherein said thickening agent is selected from the group comprising bentonite, bentones, fermented organic biopolymers, alginates, polyglycolethers, acrylate thickeners or urethane thickeners, organic carbonic esters and mixtures thereof.

13. The composition of any one of the preceding claims that is an aqueous solution with a concentration of 20-60 by weight of solid matter.

14. The composition of any one of claims 1 to 12 which is a powder. 0•

15. A composition substantially as hereinbefore described with reference to the drawing and/or Examples. 9"o 16. A method for the use of a composition of claim 14, or the production of a composition of claim 13 wherein at the place of use said powder is transferred into a solution by S: mixing with water. *00.

17. A method substantially as hereinbefore described with reference to the drawing and/or Examples.

18. A method for the acceleration of the setting and hardening of hydraulic binders as well as therefrom produced mortar and concrete wherein a composition according to any one of claims 1 to 15 or a composition produced according to P.\OPER\Snl387a5.01 Ipl docOS105) -16- claim 16 or 17 is added to a mixture comprising said hydraulic binder in an amount of from 0.1 to 10 by weight referred to the weight of hydraulic binder.

19. Use of the composition of any one of claims 1 to 15 for the acceleration of the setting and hardening of hydraulic binders, hydraulic binders in admixture with latent hydraulic binders and/or inert fillers, in particular mortar or concrete. Use of a composition of any one of claims 1 to 15 as setting and hardening accelerator in spraying mortar or spraying concrete according to the dry or wet spraying method.

21. The use of claim 20 wherein the accelerator is added to the dry binder, mortar or concrete, or to the binder, mortar or concrete mixed with water, in the conveyor pipeline, the 0 pre-wetting nozzle and/or the spray nozzle, said addition being performed with a liquid dosing apparatus directly into the mixture or into the mixing water. C 0 DATED this 5th day of October, 2005 *00* Sika Schweiz AG By DAVIES COLLISON CAVE Patent Attorneys for the Applicant