ACCELERATOR POWDER AND QUICK-SETTING BINDER COMPOSITION

Abstract

An accelerator powder for cement and also rapid-setting binder compositions which contain the accelerator powder and the use in mortar or concrete. The accelerator powder includes from 10 to 99.7% by weight of a water-insoluble mineral powder P and from 0.3 to 90% by weight of at least one compound V selected from the group consisting of alkali metal halides and alkaline earth metal halides, alkali metal nitrates and alkaline earth metal nitrates, alkali metal nitrites and alkaline earth metal nitrites, alkali metal thiocyanates and alkaline earth metal thiocyanates and hydroxyalkylamines or salts thereof, and mixtures thereof.

Claims

1. An accelerator powder for cement, comprising from 10 to 99.7% by weight of a water-insoluble mineral powder P and from 0.3 to 90% by weight of at least one compound V selected from the group consisting of alkali metal halides and alkaline earth metal halides, alkali metal nitrates and alkaline earth metal nitrates, alkali metal nitrites and alkaline earth metal nitrites, alkali metal thiocyanates and alkaline earth metal thiocyanates and hydroxyalkylamines or salts thereof, and mixtures thereof.

2. The accelerator powder as claimed in claim 1, wherein the mineral powder P is selected from the group consisting of calcium carbonate, dolomite, metakaolin and quartz flour.

3. The accelerator powder as claimed in claim 1, wherein the mineral powder P has an average particle size D50 of from 1 to 150 m.

4. The accelerator powder as claimed in claim 1, wherein the compound V comprises at least one hydroxyalkylamine.

5. The accelerator powder as claimed in claim 1, wherein the hydroxylalkylamine has been partially or completely neutralized with an inorganic or organic acid.

6. The accelerator powder as claimed in claim 1, wherein it comprises at least two different compounds V selected from the group consisting of alkali metal halides and alkaline earth metal halides, alkali metal nitrates and alkaline earth metal nitrates, alkali metal nitrites and alkaline earth metal nitrites, alkali metal thiocyanates and alkaline earth metal thiocyanates and hydroxyalkylamines, or salts thereof.

7. The accelerator powder as claimed claim 1, wherein the accelerator powder comprises from 50 to 99.7% by weight of powder P and from 0.3 to 50% by weight of at least one compound V, based on 100% by weight of the accelerator powder.

8. The accelerator powder as claimed in claim 1, wherein it also comprises a plasticizer, in an amount of from 0.3 to 10% by weight calculated as dry plasticizer and based on 100% by weight of accelerator powder.

9. The accelerator powder as claimed in claim 1, wherein it also comprises a retarder, a sugar, a phosphate or a phosphonate or salt thereof, or mixtures thereof.

10. A binder composition comprising from 10 to 95% by weight of cement and from 5 to 90% by weight of accelerator powder as claimed in claim 1, based on 100% by weight of the binder composition.

11. A concrete or mortar containing the accelerator powder as claimed in claim 1, wherein the accelerator powder is present in an amount of from 6 to 100% by weight, based on the weight of the cement present in the concrete or mortar.

12. A mortar mixture comprising: from 55 to 85 parts by weight of sand having a particle size of not more than 4 mm, from 15 to 45 parts by weight of cement, from 5 to 45% by weight of mineral powder P, based on the weight of the cement, from 0.15 to 5.0% by weight of compound V, based on the weight of the cement, from 0 to 1.0% by weight of plasticizer, based on the weight of the cement, from 0 to 1.0% by weight of retarder, based on the weight of the cement, and from 0 to 5% by weight of further additives, based on the weight of the cement, with all constituents being calculated as water-free components.

13. A method for accelerating a concrete or mortar mixture, comprising adding the accelerator powder as claimed in claim 1 to a concrete or mortar mixture, wherein the concrete or mortar mixture after mixing with water has a commencement of setting of less than 90 minutes, and an end of setting of less than 3 hours, measured using an automatic Vicat needle apparatus in accordance with DIN EN 196-3 at 20 C.

14. A method for accelerating an aqueous concrete or mortar mixture, comprising adding the accelerator powder as claim 1 to an aqueous concrete or mortar mixture, wherein the concrete or mortar mixture has such a composition that the concrete or mortar mixture containing the accelerator powder has a viscosity of from 1 to 100 Pa.Math.s, at a shear rate of 10 s.sup.1 after mixing with water, where the viscosity is determined on a concrete or mortar sample which has a maximum particle size of 2 mm, using a rheometer and the method indicated in the description.

15. A shaped body produced from a concrete or mortar mixture containing the accelerator powder as claimed in claim 1 after mixing with water and curing of the resulting mixture.

Description

EXAMPLES

[0140] Working examples which are intended to illustrate the invention described in more detail are set forth below. Of course, the invention is not restricted to these working examples described.

1. Materials Used

[0141] Omyalite 90 is a fine calcium carbonate powder having an average particle size D50 of 1.5 m, obtainable from Omya, Switzerland.

[0142] Nekafill 15 is a fine calcium carbonate powder obtainable from Kalkfabrik Netstal, Switzerland.

[0143] Sika ViscoCrete: pulverulent high-performance plasticizer Sika

[0144] ViscoCrete-225 P based on modified polycarboxylate, obtainable from Sika Deutschland GmbH.

[0145] RW fller is an uncompacted microsilica (amorphous SiO.sub.2) obtainable from RW silicium GmbH, Germany.

2. Composition and Production of the Accelerator Powders and Binder Compositions

Accelerator Powder B1 (Comparative Mixture)

[0146] 0.8 g of sodium nitrate and 0.2 g of sodium thiocyanate were mixed.

Accelerator Powder B2 (Comparative Mixture)

[0147] 1.0 g of sodium nitrate and 1.0 g of sodium thiocyanate were mixed.

Accelerator Powder B3 (Comparative Mixture)

[0148] 0.25 g of sodium nitrate, 0.14 g of sodium thiocyanate, 0.11 g of N-methyldiethanolamine and 0.7 g of Sika ViscoCrete-225 P were mixed.

Accelerator Powder B4 (According to the Invention)

[0149] 10 g of Omyalite 90 were mixed with 0.2 g of N-methyldiethanolamine.

Accelerator Powder B5 (According to the Invention)

[0150] 10 g of Omyalite 90 were mixed with 1.0 g of sodium nitrate and 0.2 g of N-methyldiethanolamine.

Accelerator Powder B6 (According to the Invention)

[0151] 10 g of Omyalite 90 were mixed with 0.25 g of sodium nitrate, 0.14 g of sodium thiocyanate, 0.11 g of N-methyldiethanolamine and 0.7 g of Sika ViscoCrete-225 P.

Accelerator Powder B7 (According to the Invention)

[0152] 10 g of Nekafill 15 were mixed with 0.25 g of sodium nitrate, 0.14 g of sodium thiocyanate, 0.11 g of N-methyldiethanolamine and 0.7 g of Sika ViscoCrete-225 P.

Accelerator Powder B8 (According to the Invention)

[0153] 10 g of Omyalite 90 were mixed with 0.2 g of sodium nitrate, 0.13 g of sodium thiocyanate, 0.1 g of N-methyldiethanolamine and 0.2 g of Sika ViscoCrete-225 P.

Accelerator Powder B9 (According to the Invention)

[0154] 20 g of Omyalite 90 were mixed with 0.2 g of sodium nitrate and 0.8 g of sodium thiocyanate.

Accelerator Powder B10 (According to the Invention)

[0155] 10 g of Omyalite 90 were mixed with 1.0 g of sodium nitrate, 0.2 g of sodium thiocyanate and 0.1 g of N-methyldiethanolamine.

Accelerator Powder B11 (According to the Invention)

[0156] 5 g of RW fller were mixed with 1.0 g of sodium nitrate, 0.2 g of sodium thiocyanate and 0.1 g of N-methyldiethanolamine.

Accelerator Powder B12 (According to the Invention)

[0157] 10 g of Omyalite 90 were mixed with 1.0 g of sodium nitrate, 0.2 g of sodium thiocyanate, 0.1 g of N-methyldiethanolamine and 0.05 g of tartaric acid.

Accelerator Powder B13 (According to the Invention)

[0158] 10 g of Omyalite 90 were mixed with 1.0 g of sodium nitrate, 0.2 g of sodium thiocyanate and 0.1 g of triethanolamine.

Rapid-Setting Binder Composition M1 (According to the Invention)

[0159] 90 g of cement (CEM I 52.5) were mixed with 10.63 g of accelerator powder B8.

Rapid-Setting Binder Compositions M2 and M3 (According to the Invention)

[0160] M2 and M3 were produced like M1 but 0.2 g of tartaric acid in the case of M2 and 0.4 g of tartaric acid in the case of M3 were added to the accelerator powder B8. Correspondingly, 10.83 g of accelerator powder in the case of M2 and 11.03 g of accelerator powder in the case of M3 were mixed with 90 g of cement.

3. Use Tests

[0161] The commencement of setting and the end of setting were determined by means of an automatic Vicat needle apparatus in accordance with DIN EN 196-3, at 20 C.

[0162] The setting time is for the purposes of this document the time interval between the end of mixing and the commencement or end of setting.

[0163] The compressive strength was determined on test specimens having dimensions of 4040160 mm in accordance with DIN EN 196-1. The test specimens were stored covered in the mold at 20 C. until testing was carried out.

3.1 Testing of the Accelerator Powders in Cement Paste

[0164] The cement and the accelerator powder were mixed for 30 seconds in a mixer (KitchenAid model ARTISAN, 5KSM150). The water in which the fluidizer had been dissolved was subsequently added and the cement paste was mixed for a further 3 minutes.

[0165] The composition of the cement pastes and the setting times measured and also compressive strengths after 2 hours are reported in Table 1 and Table 2.

TABLE-US-00001 TABLE 1 T1* T2* T3* T4* T5 T6 T7 Cement CEM I 100 90 100 100 90 90 80 52.5 R (g) Accelerator Omya- B1 B2 B4 B5 B9 powder lite 90 Amount (g) 10.0 1.0 2.0 10.2 11.2 21.0 Sika 0.2 0.2 0.2 0.2 0.2 0.2 0.2 ViscoCrete (g) Water (g) 23 23 23 23 23 23 23 Commencement 8:38 4:01 3:42 3:57 0:03 0:02 2:09 of setting (h:min) End of setting 10:53 6:38 7:31 7:17 0:13 0:07 5:39 (h:min) *Reference mixture

TABLE-US-00002 TABLE 2 T8 T9 T10 T11 Cement CEM I 90 95 90 90 52.5 R (g) Accelerator B10 B11 B12 B13 powder Amount (g) 11.3 6.3. 11.35 11.3 Sika 0.2 0.2 0.2 0.2 ViscoCrete (g) Water (g) 23 25.sup.1) 23 23 Commencement 0:03 0:07 0:07 n.m..sup.2) of setting (h:min) End of setting 0:07 0:10 0:11 n.m. (h:min) Compressive 10.4 8.5 10.7 n.m strength after 2 hours (MPa) .sup.1)In order to be able to process the cement paste, 25 g of water rather than 23 g of water had to be added. .sup.2)n.m: not measurable; setting commences during mixing.

3.2 Testing of the Rapid-Setting Binder Compositions M1 to M3

[0166] The binder compositions M1, M2 and M3 were mixed in the amounts indicated in Table 2 with water in a mixer (KitchenAid model ARTISAN, 5KSM150) for 3 minutes. Commencement of setting and end of setting of the mixtures were subsequently determined. The values found are reported in Table 3.

TABLE-US-00003 TABLE 3 T12 T13 T14 Binder composition M1 M2 M3 Amount (g) 100.63 100.83 101.03 Water (g) 22.5 22.5 22.5 Commencement of setting 0:11 0:18 0:41 (h:min) End of setting (h:min) 0:16 0:36 1:26

3.3 Testing of the Accelerator Powders in a Mortar Mixture

[0167] The cement was homogeneously mixed with the accelerator powder in a mixer (KitchenAid model ARTISAN, 5KSM150). The sand and the water were subsequently added and the mortar was mixed again for 3 minutes. The composition of the mortars and the setting times measured are reported in Table 4.

TABLE-US-00004 TABLE 4 T15* T16* T17* T18* T19 T20 Sand 0.08/2 mm 300 300 300 300 300 300 (g) Cement CEM 100 100 100 100 100 100 I 52.5 (g) Accelerator B3 Omya- Nekafill B6 B7 powder lite 90 15 Amount (g) 1.2 10 10 11.2 11.2 Sika 0.5 0.7 0.7 ViscoCrete (g) Water (g) 39 39 39 39 39 39 Commencement 5:49 4:09 5:40 7:10 0:12 0:13 of setting (h:min) End of setting 8:39 6:58 7:34 9:27 0:44 1:17 (h:min) *Reference mixture