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EP-3638635-B1 - COMPOSITE CEMENT AND METHOD OF MANUFACTURING COMPOSITE CEMENT

EP3638635B1EP 3638635 B1EP3638635 B1EP 3638635B1EP-3638635-B1

Inventors

  • Zajac, Maciej
  • Ben Haha, Mohsen
  • BOLTE, GERD

Dates

Publication Date
20260513
Application Date
20180604

Claims (14)

  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, wherein the composite cement comprises 30 to 65 % by weight Portland cement clinker, 20 to 40 % by weight latent hydraulic material, and 15 to 20 % by weight mineral filler, all with respect to the total amount of composite cement.
  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 or 2, 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 anyone of claims 1 to 3, 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.
  5. The composite cement according to anyone of claims 1 to 4, further containing a calcium sulfate, as anhydrite, hemi hydrate or gypsum or any mixture of the foregoing.
  6. The composite cement according to anyone of claims 1 to 5, wherein an amine grinding aid is present during grinding of the Portland cement clinker and latent hydraulic material.
  7. The composite cement according to claim 6, wherein the amine grinding aid is selected from Triethanolamine, Triisopropanolamine, Diethanolisopropanolamine or any mixture of the foregoing.
  8. 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, wherein the composite cement comprises 30 to 65 % by weight Portland cement clinker, 20 to 40 % by weight latent hydraulic material, and 15 to 20 % by weight mineral filler, all with respect to the total amount of composite cement.
  9. The method according to claim 8, wherein the latent hydraulic material and portland cement clinker are ground to a fineness from 2500 cm 2 /g to 8000 cm 2 /g according to Blaine
  10. The method according to claim 8 or 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.
  11. A binder containing the composite cement according to anyone of claims 1 to 7 and an admixture and/or an additive.
  12. The binder according to claim 11, 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.
  13. The binder according to claim 12, 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.
  14. A use of the composite cement according to anyone of claims 1 to 7 or the binder according to anyone of claims 11 to 13 as building material, wherein the composite cement or the binder 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

The present invention relates to a composite cement obtainable by grinding Portland cement clinker and a latent hydraulic material together to provide a ground mixture and combining the ground mixture with a mineral filler, to a method of manufacturing the cement as well as to binders containing the cement and to using the cement or binder as building material. Portland composite cements are increasingly used. In composite cements the Portland cement clinker, frequently referred to as clinker hereinafter, is replaced by other constituents like granulated blast furnace slag, abbreviated slag or GBFS hereinafter, fly ash and limestone. The composite cement is typically composed of two reactive components. Within the last years the production of composite cements has reached a constant level due to the limited availability of GBFS and fly ash. Thus, ternary blends including limestone move into focus. In order to increase the amount of composite cement an increase of the proportion of ternary blends including the high limestone proportions is required. Increasing amounts of limestone (or other inert fillers) affect the strength of the hardened binder. The early compressive strength of the composite cements also suffers from a low reactivity of the slag. One solution is the addition of alkali sulphate that improves the evolution of the compressive strength of composite cements. This measure is limited by allowable total alkali content. Another typical solution is an increase of the fineness of the cement clinker. The grindability of clinker and the other components slag, fly ash, limestone differs from each other and also a given component shows some variability of grinding behaviour depending on actual composition. Thus, it is generally believed that higher fineness in turn requires a separate grinding of clinker and the other cement components. Several technical reports indicate that separate grinding of the cement components followed by blending them (homogenization) is particularly suited to Portland-slag cement or blast furnace cement production, where the significant difference in grindability of the different constituents can be problematic for the inter-grinding process and blending separately ground slag with cement or clinker is beneficial: Cementitious Materials, Technical Report No. 74 Concrete Society Working Party, Published December 2011, http://www.concrete.org.uk/publications-technical-reports.aspFuture Grinding Technologies - Report about Phase 1: Evaluation of Roundtable Event, technical report TR 127/2015, European Cement Research Academy, Published 2015, https://ecra-online.org/research/future-grinding-technologies/J. Trenkwald, H.M. Ludwig, Herstellung hüttensandhaltiger Zemente durch getrenntes Mahlen und Mischen im Zementwerk Karlstadt, ZKG 09/2001. WO 2015/045194 A1 describes composite cements containing cement, granulated blast furnace slag, limestone powder, and an alkanolamine and states that 1 to 10 % by weight limestone powder are possible. Grinding cement and limestone together and adding separately ground slag is recommended. Several publications find that a tailored particle size distribution of cement components provides appropriate performance of composite cements that have high cement clinker replacement ratio: M. Onera, K. Erdogdu, A. Gunlu, Effect of components fineness on strength of blast furnace slag cement, Cement and Concrete Research 33 (2003) 463 - 469Tongsheng Zhang, Qijun Yu, Jiangxiong Wei, Pingping Zhang, Peixin Chen, A gap-graded particle size distribution for blended cements: Analytical approach and experimental validation, Powder Technology 214 (2011) 259 - 268Tongsheng Zhang, Qijun Yu, Jiangxiong Wei, Pingping Zhang, A new gap-graded particle size distribution and resulting consequences on properties of blended cement, Cement & Concrete Composites 33 (2011) 543 - 550Tongsheng Zhang, Qijun Yu, Jiangxiong Wei, Pingping Zhang, Effects of size fraction on composition and fundamental properties of Portland cement, Construction and Building Materials 25 (2011) 3038 - 3043S. Palm, A. Wolter, Strength development of multi-composite cements with optimized void filling, CEMENT INTERNATIONAL 01/2011, pp. 56 - 64 Separate grinding requires more installation and thereby increases capital expenditure. Thus, there exists a need to provide composite binders that develop sufficient strength while allowing a high clinker replacement ratio. An improvement of the early compressive strength evolution as well as a reduction of the water demand of the composite cement is desirable. It was now surprisingly found that ternary cements from latent hydraulic materials and Portland cement clinker ground together and combined with separately ground mineral fillers, especially limestone, show good performance while limiting clinker demand. Accordingly, the present invention solves the above mentioned problems by providing a composite cement according to claim 1. The invention further solves