COMPOSITE CEMENT AND METHOD OF MANUFACTURING COMPOSITE CEMENT

Abstract

The present invention relates to a composite cement obtainable by grinding Portland cement clinker and latent hydraulic material together, preferably in the presence of at least one amine grinding aid, to provide a ground mixture and combining the ground mixture with a mineral filler. It further relates to a method of manufacturing the composite cement comprising the steps of grinding a latent hydraulic material and a portland cement clinker together, preferably in the presence of at least one amine, to provide a ground mixture and combining the ground mixture with one or more mineral fillers as well as to binders and to using the cement or binders as building material.

Claims

1. A composite cement obtainable by grinding a latent hydraulic material and a portland cement clinker together to provide a ground mixture and combining the ground mixture with one or more mineral fillers.

2. The composite cement according to claim 1, wherein the latent hydraulic material is slag, especially granulated blast furnace slag, and/or calcium rich fly ash.

3. The composite cement according to claim 1, wherein the mineral filler is stone dust, preferably selected from limestone, dolomite, marl, granite or a mixture of two or more of these, most preferably limestone.

4. The composite cement according to claim 1, wherein the composite cement comprises 30 to 75% by weight Portland cement clinker, 20 to 60% by weight latent hydraulic material, and 5 to 20% by weight mineral filler, preferably 50 to 65% by weight Portland cement clinker, 30 to 40% by weight latent hydraulic material, and 5 to 15% by weight mineral filler, more preferred 50% by weight of Portland cement clinker, 40% by weight of latent hydraulic material, and 10% by weight mineral filler, all with respect to the total amount of composite cement.

5. The composite cement according to claim 1, wherein a ratio of the Portland cement clinker to the latent hydraulic material is from 0.8 to 3.0, preferably from 1.0 to 2.0.

6. The composite cement according to claim 1, further containing a calcium sulfate, as anhydrite, hemi hydrate or gypsum or any mixture of the foregoing.

7. The composite cement according to claim 1, wherein an amine grinding aid is present during grinding of the Portland cement clinker and latent hydraulic material.

8. The composite cement according to claim 7, wherein the amine grinding aid is selected from Triethanolamine, Triisopropanolamine, Diethanolisopropanolamine or any mixture of the foregoing.

9. A method of manufacturing a composite cement comprising the steps of grinding a latent hydraulic material and a portland cement clinker together, preferably in the presence of at least one amine, to provide a ground mixture and combining the ground mixture with one or more mineral fillers.

10. The method according to claim 9, wherein the latent hydraulic material and portland cement clinker are ground to a fineness from 2500 cm.sup.2/g to 8000 cm.sup.2/g according to Blaine

11. The method according to claim 9, wherein the ground mixture is combined with the mineral filler by homogenising in a device used for grinding and/or in a static or dynamic powder mixing device.

12. A binder containing the composite cement according to claim 1 and an admixture and/or an additive.

13. The binder according to claim 12, containing a plasticizer as the admixture, preferably one or more of lignosulfonates, hydroxy carboxylic acids and salts thereof, gluconates, fruit acids, phosphonates, phosphates, boric acid and salts thereof.

14. The binder according to claim 13, further containing a sulfate, preferably calcium sulfate-anhydrite, calcium sulfate-hemi hydrate, calcium sulfate-dihydrate (gypsum), sodium sulfate, potassium sulfate or any mixture of the foregoing.

15. A use of the composite cement according to claim 1 as building material, wherein the composite cement is mixed with aggregates to form concrete for pre-cast units, such as panels, beams, road parts, or to form cast-in situ concrete for the construction of buildings, dams, etc., or to provide a construction material such as mortar, screed, or tile adhesive.

Description

EXAMPLES

[0044] Two clinkers from a cement plant of HeidelbergCement AG, granulated blast furnace slag used by HeidelbergCement AG for cement production and limestone from a cement plant of HeidelbergCement AG were used. The chemical composition determined by XRF is listed in table 1. LOI means loss on ignition, i.e. calcination at the given temperature. Limestone was used as the mineral filler.

TABLE-US-00001 TABLE 1 Clinker Clinker Lime- Calcium 1 2 Slag stone sulfate LOI 0.29 (at 0.23 (at (+1.66) (at 42.8 (at 4.1 (at 950 C.) 950 C.) 950 C.) 1050 C.) 1050 C.) SiO2 20.42 21.27 35.77 1.69 2.44 Al2O3 5.58 5.72 11.76 0.55 0.77 TiO2 0.29 0.28 1.02 0.03 0.023 MnO 0.05 0.04 0.26 0.04 0.00 Fe2O3 3.77 3.26 0.42 0.21 0.27 CaO 65.19 65.64 42.73 53.71 37.89 MgO 1.59 1.81 5.07 0.71 1.63 K2O 1.2 0.9 0.39 0.05 0.18 Na2O 0.18 0.07 0.08 0.01 0 SO3 0.94 0.54 2.41 0.09 51.44 P2O5 0.19 0.13 0.02 0.04 0.02 Sum 99.69 99.89 99.93 99.93 98.77 LOI

[0045] The cement clinker, slag and limestone were ground in a laboratory 3.5 kg ball mill (load of the mill). The time of grinding was 90 minutes for examples 1 to 3 and 60 minutes for example 4. Materials were ground separately or coground with and without addition of amines. Amines were introduced directly into the mill. The same energy was used for grinding the materials without and with additives. If needed, materials were crushed in a laboratory jaw crusher before grinding. Subsequently the composite cements were prepared by homogenization by grinding in the ball mill for 15 minutes. The cement composition was 50% by weight cement clinker, 40% by weight of slag and 10% by weight limestone according to EN197-1 standard. SO.sub.3 content was 2.7% by weight. The performance of the cement in mortar was tested according to EN196-1 (compressive strength) and EN196-3 (water demand).

Example 1

[0046] The effect of grinding binder components together or separately was tested. Further the effect of adding amines during grinding was examined. Clinker 1 and slag were ground either together (Inv1, Inv2) or separately (Com1, Com2, Com3) with the same amount of Diethanolisopropanolamine (DEIPA) added relative to the binder (Inv 2, Com2, Com3) or without added amine (Inv1, Com1). Further, the effect of co-grinding the mineral filler was examined (Com4 and Com5). Table 2 summarizes the samples, measured water demands, and compressive strengths.

[0047] It is readily apparent that co-grinding of clinker and slag in the samples according to the invention resulted in better compressive strength, independently of the amine additions, as compared to the separately ground samples. Also, co-grinding the mineral filler adversely affects the final strength and additionally results in the highest water demand. While an addition of amine during grinding generally improves the strength achieved, the optimal strength is only provided by co-grinding and addition of amine. The composite cement according to the invention can be made without investment into a separate mill for the latent hydraulic material.

TABLE-US-00002 TABLE 2 compressive Amount of water strength [MPa] after Sample clinker and slag ground DEIPA added to demand 1 d 2 d 7 d 28 d Inv1 together 27.0% 8.4 18.1 35.4 51.6 Inv2 together 0.0278 wt % combined clinker + slag 28.0% 12.0 21.4 40.9 60.0 Com1 separately 26.5% 6.4 15.8 33.1 51.1 Com2 separately 0.05 wt % clinker 27.0% 11.5 20.7 38.1 57.1 Com3 separately 0.0627 wt % slag 27.5% 10.5 19.1 38.6 57.3 Com4 together with limestone 28.5% 8.0 17.3 34.1 47.8 Com5 together with limestone 0.025 wt % clinker + slag + limestone 27.0% 10.1 19.1 36.9 54.2

Example 2

[0048] In this example another clinker was tested and the effect of different amounts of DEIPA. Clinker 2 and slag were ground either together (Inv10, Inv11, Inv12) or separately (Com10-18) and different amounts of DEIPA were added (Inv11, Inv12 and Com11-18). Table 3 summarizes the samples, measured water demands, and compressive strengths.

[0049] This example confirms that co-grinding cement and slag increases strength compared to separate grinding. Grinding with DEIPA results in an additional strength increase. Thus, with co-grinding of clinker and slag together with the addition of an amine the amount of filler can be considerably increased still obtaining sufficient strength.

Example 3

[0050] In this example Triisopropanolamine (TIPA) was used as amine, in all other respects it was proceeded as in example 2. The samples listed in table 4 were made and examined, the results are also listed in table 4.

[0051] This example shows that the effect of TIPA is the same as that of DEIPA. But again, contrary to the prior art, grinding clinker and slag together achieves a significant strength increase.

TABLE-US-00003 TABLE 3 compressive clinker and slag Amount of water strength [MPa] after Sample ground DEIPA added to demand 1 d 2 d 7 d 28 d Inv10 together 31.0% 10.4 19.3 39.2 55.0 Inv11 together 0.025 wt % combined clinker + slag 33.5% 13.6 24.5 47.2 62.8 Inv12 together 0.05 wt % combined clinker + slag 33.5% 15.1 25.9 48.2 63.2 Com10 separately 33.5% 8.0 14.9 35.1 51.7 Com11 separately 0.05 wt % clinker 33.0% 13.1 22.5 43.1 60.6 Com12 separately 0.1 wt % clinker 35.5% 13.3 23.8 43.8 61.9 Com13 separately 0.005 wt % clinker 29.5% 9.4 18.3 38.3 57.0 Com14 separately 0.01 wt % clinker 31.0% 12.0 20.9 41.2 58.1 Com15 separately 0.025 wt % clinker 30.0% 10.0 19.0 37.6 57.4 Com16 separately 0.1 wt % slag 33.0% 9.7 18.7 40.6 59.7 Com17 separately 0.2 wt % clinker 36.0% 11.4 22.0 45.1 60.4 Com18 separately 0.1 wt % each of clinker and slag 37.0% 10.0 22.7 46.2 65.1

TABLE-US-00004 TABLE 4 compressive clinker and slag Amount of water strength [MPa] after Sample ground TIPA added to demand 1 d 2 d 7 d 28 d Inv20 together 0.05 wt % combined clinker + slag 34.5% 12.4 23.5 46.9 65.3 Com20 separately 0.1 wt % clinker 34.5% 11.2 21.9 43.3 59.5