EP3353134A1

EP3353134A1 - 3d printing of components and structures with bct cement

Info

Publication number: EP3353134A1
Application number: EP16767139.5A
Authority: EP
Inventors: Wolfgang Dienemann; Kai Wortmann
Original assignee: HeidelbergCement AG
Current assignee: Heidelberg Materials AG
Priority date: 2015-09-22
Filing date: 2016-09-10
Publication date: 2018-08-01
Also published as: WO2017050421A1; CA2999088A1; EA201890783A1; CN108025976A; US20190009428A1; AU2016325200A1; EP3147269A1

Abstract

The present invention relates to the use of belite calciumsulfoaluminate ternesite cement for producing components and structures by means of 3D printing and a method for producing components and structures by the 3D printing of belite calciumsulfoaluminate ternesite cement.

Description

3D printing of components and buildings with BCT cement

The present invention relates to the use of belite-calcium sulfoaluminate ternesite (BCT) cement for the production of components and

Buildings using 3D printing and a process of manufacturing components and buildings by 3D printing of BCT cement.

3D printing has been developed as part of the rapid prototyping process, i. For manufacturing processes that have the goal of converting existing CAD data directly into prototypes or workpieces, if possible without manual detours or forms. In rapid prototyping, as a rule, the workpiece is built up layer-by-layer from shapeless or form-neutral material using physical and / or chemical effects.

In addition to the production of prototypes, the production of end products is gaining in importance. Under the name Contour Crafting, Prof. Behrokh Khoshnevis proposed the use of 3D printing in the US for the construction of buildings. The outer contours of the walls are printed in layers with rapid cement and the space, if necessary, after the insertion of a reinforcement, filled with normal concrete. This approach is expensive.

In China, Ma Yihe developed a system in which components such as walls and ceilings are printed and then mounted to the building analogous to the prefabricated house, see, inter alia. CN 104372884 A, CN 204081129 U and CN 203654462 U. The construction of a villa from such parts has been described e.g. by W. Kempkens on www.ingenieur.de on 31.1.2015 under the title "Chinese engineers build villa with 3D printer" reports.

A proposal for a suitable as a building material for 3D printing cement mixture can be found in CN 104310918 A. Accordingly, the building material 33 - 44% cement, 0 - 8% inorganic powder, 32 - 38% special sand, 2.5 - 3% Polymer and a mixture of additives include. The cement used is a mixture of calcium sulfoaluminate cement and Portland cement.

The disadvantage of this is that the complex additive mixture and also the additives polymer and inorganic powder must be continuously adapted to the current cement quality and the required quantities

Additive and polymer also make the building material relatively expensive.

There is therefore the problem that with the currently used techniques / building materials, the cost or expense for a wide application are still too high. Accordingly, it was an object of the invention to provide a cheaper and / or simpler building material.

Surprisingly, it has now been found that a BCT cement, if one adds little or no retarder, both a sufficient early strength and a useful ultimate strength developed and is suitable without complex additive mixtures as a building material for 3D printing of components and buildings.

The above object is therefore achieved by the use of BCT cement for 3D printing of components and buildings, and by a method for manufacturing components and buildings, comprising the steps of providing BCT cement and 3D printing of the component or building.

To simplify the further description, the following abbreviations customary in the cement industry are used: H - H ₂ O, C - CaO, A - Al ₂ O ₃₎ F - Fe ₂ O ₃ , M - MgO, S - SiO ₂ and $ - S0 ₃ . In addition, compounds are usually given in their pure form, without explicit mention of mixed series / substitution by foreign ions, etc. as they are common in technical and industrial materials. As understood by any person skilled in the art, the composition of the compounds mentioned by name in this invention, such as clinker phases, depending on the chemistry of the raw meal and the nature of the Preparation, by substitution with various foreign ions vary. Such compounds are included within the scope of the invention when referring to the pure form, unless otherwise indicated.

Unless otherwise indicated, by "reactive" is meant a hydraulic reactivity.

[0001] In the context of the present invention, clinker means a sintered product which is obtained by firing a starting material at elevated temperature and contains at least one hydraulically reactive phase. Firing means activation by altering one or more of the properties of chemistry, crystallinity, phase composition, three-dimensional arrangement, and bonding behavior of the framework atoms by the addition of thermal energy. The starting material may in individual cases also be a single raw material if it contains all the desired substances in the correct relation, but this is the exception. The starting material may also contain mineralizers. Mineralizers are substances that act as fluxes and / or lower the temperature necessary to form a melt and / or those that promote the formation of the clinker compound, such as by solid solution formation and / or phase stabilization. Mineralizers may be included in the starting material as an ingredient or added in a targeted manner.

Cement is a ground with or without the addition of other components ground clinker, but also other hydraulically hardening materials and mixtures, for example, but not exclusively Sulfathüttenzement Geopolymerzement and obtained by hydrothermal conversion Belitzement. A binder or binder mixture refers to a material which hydraulically hardens in contact with water and which contains cement and typically but not necessarily further finely ground components. The binder comes after addition of water, usually also aggregate and, if necessary, additives, as a building material for use. Clinker substitute material or SCM refers to a pozzolanic and / or latent-hydraulic material that replaces a part of the clinker in a cement or a binder. Latent hydraulic materials have a composition which, when in contact with water, allows for hydraulic hardening, typically requiring an activator for hardening in technically useful periods. By stimulator or activator is meant a material which accelerates the hardening of latent-hydraulic materials. It may be an additive, such as sulfate or calcium (hydr) oxide and / or products of the hydraulic reaction of the clinker, for example, set calcium silicates in the hardening calcium hydroxide free, which acts as an exciter. Pozzolanic materials are characterized by a reactive silica content which, upon hydration of a binder with calcium hydroxide present in the aqueous phase, translates into strength-forming calcium silicate hydrate phases. In practice, the boundary between latent-hydraulic and pozzolanic materials is fluid, eg flyashes may be pozzolanic or latent-hydraulic materials, depending on the content of calcium oxide. By SCM is meant both latent-hydraulic and pozzolanic materials. However, SCM is to be distinguished from unreactive, mineral additives, such as

Rock flour, which have no part in the hydraulic conversion of the binder. Partly, SCM are combined together with such additives as mineral additives.

A clinker can already contain all the necessary or desired phases and come after grinding to cement directly as a binder used. Frequently, the composition of the binder by mixing cement and other components, according to the invention at least the clinker replacement material obtained and also two or more clinker and / or cements are possible, the mixing already before (or during) the grinding and / or in the ground state and / or in the preparation of the binder. Unless a date of mixing is expressly stated, The following descriptions refer to binders (and cements) which are not limited in this respect.

BCT cement is known per se. Its preparation is described, for example, in WO 2013/023731 A1 and WO 2013/023729 A1, BCT cements in WO 2013/023728 A1. Briefly, either a separate production of a ternesite cement and mixing with a calcium sulphate inat cement (C $ A) or the production of a BCT cement in a two-stage process of sintering and tempering can take place. In the two-stage preparation, a raw meal mixture of suitable composition is first sintered above 1200 ° C to achieve good conversion of the starting materials and to form sufficient C5S (Ye'elimit) and C2S (Belit). In the second step, the clinker intermediate product is tempered in a temperature range of 1200 to 750 ° C to obtain sufficient amounts of C ₅ S2 $ (ternesite). If separate production of C $ A and ternesite cement, the C $ A can be generated as known per se. The ternesite cement is produced separately by sintering a suitable raw meal at a temperature that is optimized for high levels of ternesite and does not have to consider the levels of Ye'elimit and Belit. Of course, C $ A can also be added to the BCT cement produced in the two-stage process in order to optimize the composition. Of course, otherwise prepared BCT cement is also suitable for use and the method of the present invention.

The BCT clinker obtained in the two-stage process usually contains the following main phases:

5 to 75% by weight C ₅ S ₂ $

- 5 to 70 wt .-% C ₄ A ₃ $ and

- up to 80 wt .-% C ₂ S.

As secondary phases are, for example, calcium silicates, sulfates, calcium aluminates, spinels, representatives of the melilite group, periclase, free lime, quartz and / or a glass phase, are preferably present at a level of from 0.1% to 30%, preferably from 5% to 20%, and most preferably from 10% to 15%, by weight. The type and amount of one or more secondary phases in relation to the main components can be controlled by the weight ratios CaO / Al ₂ O ₃ (± Fe ₂ O ₃ ), CaO / SiO ₂ and the proportion of the sulfate carrier in the raw meal mixture. A preferred secondary phase is C ₂ A _y Fi _-y , with y being from 0.2 to 0.8, preferably from 0.4 to 0.6, especially in the form C ₄ AF, which is preferably in an amount of from 3 to 30 Wt .-%, particularly preferably from 5 to 25 wt .-% and most preferably from 10 to 20 wt .-% is present. Preferably, the BCT clinker contains the following amounts of the main phases: 10 - 60 wt .-%, in particular 20 - 40 wt .-% C ₅ S ₂ $, 10 - 60 wt .-%, in particular 20 - 45 wt .-% C ₄ A ₃ $ and 10-65% by weight, in particular 20-50% by weight C ₂ S. The free-lime content is preferably below 5% by weight, in particular below 2% by weight and very particularly preferably below 1 wt .-%. It may preferably be an X-ray amorphous phase or glass phase in an amount of 1 to 10 wt .-%, preferably 2 to 8 wt .-% and in particular 3 to 5 wt .-% present. The proportions refer to the total amount of clinker, wherein in each clinker, the sum of all phases contained is 100%.

A separately produced ternesite clinker usually includes

- 20 to 95 wt .-% C ₅ S ₂ $

0 to 15% by weight C ₄ A ₃ $

0 to 30% by weight C ₄ AF

0 to 20% by weight of reactive aluminates

- 0 to 25 wt .-% periclase and

- 0 to 30 wt .-% further secondary phases.

As further minor phases, for example, but not limited to, alkali / alkaline earth sulfates, quartzes, spinels, olivines, pyroxenes, members of the melilite and merwinite group, apatites, ellestadites, silicocarnotite, free lime, Spurrit, quartz and / or an X-ray amorphous Phase existence / a glass phase, in one share from 0.1 wt .-% - 30 wt .-%, preferably from 2 wt .-% - 20 wt .-% and particularly preferably from 5 wt .-% - 15 wt .-% occur. The ternesite clinker preferably contains the following amounts of the phases mentioned: 30-95% by weight, in particular 40-90% by weight C ₅ S ₂ $, 3-12% by weight, in particular 5-10% by weight % C4A ₃ $ and 5-70% by weight, in particular 10-60% by weight C ₂ S, 5-20% by weight, in particular 8-15% by weight C ₂ (A _y F (i _{) y} )), 1 - 15 wt .-%, in particular 3 - 10 wt .-% of reactive aluminates (eg C ₃ A, CA, C12A7 ...) and 1-15 wt .-%, in particular 2-10 wt. -% periclas. The free-lime content of the clinker is below 5 wt .-%, preferably below 2 wt .-% and particularly preferably below

1% by weight. In a preferred embodiment, the ternesite clinker contains 1-10% by weight, preferably 2-8% by weight and even more preferably 3-5% by weight of at least one X-ray amorphous phase / glass phase.

For the production of BCT and ternesite clinker raw materials are used which provide at least CaO, SiO ₂ and for BCT clinker and Al ₂ O ₃ . Secondarily, at least some secondary raw materials are preferably used in order to supply them to an advantageous use and to conserve natural resources. Suitable raw materials include, but are not limited to, limestone, bauxite, clay / cobblestone, basalts, periodites, dunes, ingnimbrites, carbonatites, ashes / slags / high and low quality blastfurnace slags (mineralogy / glass content, reactivity, etc.), various heap materials, Red and brown muds, natural sulphate carriers, desulphurisation sludges, phosphogypsum, etc. Since the raw materials which provide Al ₂ O ₃ almost always contain Fe ₂ O ₃ , ye'elimit is normally in the form of C ₄ (A _x Fi _{). x} ) ₃ $ with x from 0.1 to 1, preferably from 0.8 to 0.95, before, which is advantageous because the mixed phase is particularly reactive with iron.

Suitable C $ A can be prepared in a conventional manner and are also commercially available, for example: Lafarge Aether®:

Bellt (a; +/- ß) C ₂ S 40 - 75%; Ye'elimit C ₄ A ₃ $ 15-35%;

Ferrite C ₂ (A, F) 5-25%; Secondary phases 0.1 - 10%

Lafarge Rockfast®:

Belite (a; +/- β) C ₂ S 0-10%; Ye'elimit C4A3 $ 50 - 65%

Aluminate CA 10-25%; Gehlenite C ₂ AS 10-25%;

Ferrite C ₂ (A, F) 0-10%; Secondary phases 0-10%

Italcementi Alipre®:

Belit (a; +/- β) C ₂ S 10-25%; Ye'elimit C4A ₃ $ 50 - 65%;

Anhydrite C $ 0 - 25%; Secondary phases 1 - 20%

Cemex CSA:

Belit (a; +/- β) C ₂ S 10-30%; Ye'elimit C ₄ A3 $ 20 - 40%

Anhydrite C $>1%; Alite C ₃ S> 1 -30%;

Free lime CaO <0.5 - 6%; Portlandite Ca (OH) ₂ 0-7%;

Secondary phases 0 - 10%

Denka® CSA

Belite (a; +/- β) C ₂ S 0-10%; Ye'elimit C4A ₃ $ 15-25%;

Anhydrite C ₂ (A, F) 30-40%; Portlandite Ca (OH) ₂ 20-35%;

Free Lime CaO 1-10%; Secondary phases 0-10%

China Type II & III CSA

Belit (a; +/- β) C ₂ S 10-25%; Ye'elimit C ₄ A ₃ $ 60 - 70%;

Ferrite C ₂ (A, F) 1-15%; Secondary phases 1 - 15%

Barnstone CSA

Belit (a; +/- β) C ₂ S 22%; Ye'elimit C ₄ A3 $ 60%;

Aluminate Ci ₂ A ₇ 5%; Alit C ₃ S 8%;

Ferrite C2 (A, F) 4%; Secondary phases 1%.

These C $ A cements contain partial ternesite as a secondary phase, but usually (much) not enough. In addition, a separately prepared ternesite is usually more reactive because it has been sintered at a lower temperature. Therefore, to provide the BCT cement used in the present invention, it is preferable Mixture of C $ A and ternesite cement produced or used in a two-step process BCT cement used.

Typical compositions for preferred BCT cements are shown in comparison with Portland cement (OPC) in the following table.

Table 1

While in Portland cement alite is responsible for the early strength, if necessary. With the addition of C $ A also Ye'elimit, the rapid strength development is based on BCT cement alone on the Ye'elimit to 2 days. Its proportion must therefore not be too low according to the invention and is at least 20 wt .-%. Ternesite and Belit are crucial for ultimate strength after 28 days and more. At least 40% by weight of belite and at least 5% by weight of ternesite should be present. One advantage of BCT technology is the higher reactivity of ternesite compared to belit in the OPC. In some cases, after 24 hours, a high conversion in the course of hydration can be detected.

Due to the very high reactivity of Ye'elimit BCT cements have a similar shortened open time as Portland cement, if it does not contain gypsum as a retarder. Time periods measured in laboratory tests range from around one minute to 20 minutes. In contrast to Portland Clinker-based cements without delayed-acting sulfate carriers, high early strengths can be measured with BCT cements. A great advantage of BCT cements is thus that neither the cement nor the building material made from it imperative hardening-controlling additives need. However, it is within the scope of the invention to adjust by the additional use of a further optimization of the properties.

Accordingly, in the building material in addition to aggregate and water and one or more additives may be included, and additives are not excluded. Especially for cost reasons, it is preferable to use no or only a few additives and these only in small quantities.

The fineness of the cement (Blaine value) is usually in

Range of 2500 cm ² / g up to 10000 cm ² / g, preferably in the range of 3500 cm ² / g to 6000 cn Vg.

The aggregate must be adjusted in the fineness of the 3D printing device, therefore, in general, aggregate with a particle size of up to 32 mm, preferably up to 8 mm, in particular up to 4 mm

(Sand), used. It is not necessary to use a special aggregate, all aggregates approved for concrete are suitable. Thus, sand and / or crushed sand and / or gravel and / or rocks and / or recycled aggregates of natural origin and / or from industrial production as well as combinations of two or more thereof may be used.

The weight ratio of BCT cement to aggregate is usually from 1: 2 to 1: 8, preferably from 1: 3 to 1: 5. It depends essentially on the required green strength of the building material.

The water / cement value is typically in the range of 0.25 to 0.8, preferably 0.3 to 0.5. When using clinker replacement materials such as fly ash granulated slag or microsilica, the mass ratio of BCT cement:

Clinker substitute material 1: 0.7 to 1: 0.1, preferably 1: 0.3 to 1: 0.2.

Commercially available concrete admixtures may, if necessary, be used up to the maximum dosages specified by the manufacturer. Should adverse retarding additives be required, gluconates, fruit acids, phosphates, phosphonates and borates and also mixtures thereof, and in particular phosphates, phosphonates or borates and mixtures thereof may be used.

Inert additives may be added to adjust the properties in varying proportions by mass, as required. To improve the green strength z. B. commercially available fibers (steel, plastic, glass or carbonate) are used.

For design elaboration commercial concrete pigments based on carbon black for black or on iron oxide also for black and red, brown or yellow concrete can be used. Chromium dioxide based pigments can be used to obtain green concrete and titanium dioxide (optically inactive) to lighten the predominant gray tone.

A photocatalyst, in particular catalytically active titanium dioxide can be added to achieve air improvements by reducing NO _x at the component surface.

All pigments or other additives are used in the quantities customary for concrete.

Therefore, the building material used in the invention therefore comprises at least BCT cement, aggregate and water and may consist of these. Optionally, at least one of clinker substitute material, additive and additive is additionally included. Preferably clinker replacement material (s) are included. One or more retarding or accelerating additives are added only when needed.

This building material is provided according to the invention and molded by SD printer into a component (e.g., walls, ceilings, floorboards) or buildings. The printer must of course be adapted to the parts to be manufactured and the building material as material. Such printers are known.

The inventive method thus allows to produce components and buildings in 3D printing quickly and according to individual plans. No forms are needed. There is also no or very little waste. In comparison to the known Contuor crafting and the e.g. from CN 104 310918 A known building materials BCT cement based building material is cheaper and easier. Since fewer components are needed, errors in mixing (dosing) are minimized. Even a complex control and adjustment of the amounts of various additives omitted. It can be worked with only one building material.

The invention will be explained with reference to the following examples, but without being limited to the specifically described embodiments. Unless otherwise stated or necessarily different from the context, percentages are based on weight, in case of doubt on the total weight of the mixture.

The invention also relates to all combinations of preferred embodiments, as far as they are not mutually exclusive. The information "about" or "approx." in conjunction with a numerical value mean that at least 10% higher or lower values, or 5% higher or higher lower values and in any case by 1% higher or lower values are included.

Example 1

For a BCT cement solidification start and end according to DIN EN 196 Part 3 and strengths after 1, 2, 7, 28 and 90 days according to DIN EN 196 Part 1 were determined on two sample series. The BCT cement had the following composition according to X-ray fluorescence analysis:

The major phases were 24.8 wt% yelimite (CA ₃ $), 52.4 wt% belite (β-C ₂ S), and 8.7 wt% ferrites (C4AF / C2F). The cement was mixed with sand according to DIN EN 196 part 1 in the ratio 1: 3 and the mixture with water in the ratio cement: water of 1: 0.5 made.

The start of solidification was 20 minutes and the solidification end at 30 minutes. The measured compressive strengths are shown in FIG. Two series were each measured with three specimens, so that each of the two displayed values represents an average value of 6 measurements for one time point. The measured strengths show that even without the addition of retarding or accelerating additives quickly sufficient strength is achieved and the final strength results even without reinforcement or other measures statically stable components or buildings.

Claims

claims

1. Use of Belit-calcium sulfoaluminate-ternesite cement as a building material for the production of components and buildings by 3D printing.

2. Use according to claim 1, characterized in that the

Beiit-calcium sulphoaluminate cement Ternesit

5 to 75% by weight C ₅ S ₂ $

- 5 to 70% by weight CA ₃ $

From 1 to 80% by weight of C ₂ S and

- 0 to 30% by weight, secondary phases

contains, wherein the sum of all phases contained is 100 wt .-%.

3. Use according to claim 1 or 2, characterized in that the secondary phases in the belite-calcium sulfoaluminate-ternesite cement one or more of calcium silicates, sulfates, calcium aluminates,

Spinel, Melilite group, periclase, free lime, quartz and / or a glass phase.

4. Use according to any one of claims 1 to 3, characterized in that the secondary phases in a proportion of 0.1 wt .-% to 30 wt .-%, in particular from 5 wt .-% to 20 wt .-% and especially preferably from 10% to 15% by weight.

5. Use according to one of claims 1 to 4, characterized

in that the belite-calcium sulfoaluminate-ternesite cement contains 10 to 60 wt.%, in particular 20 to 40 wt.% C ₅ S2 $, 10 to 60 wt.%, in particular 20 to 45 wt.% C ₄ A ₃ $ and 10 to 65 wt .-%, in particular 20 to 50 wt .-% C ₂ S contains. Use according to one of claims 1 to 5, characterized in that the free-lime content in Belit-calcium sulfoaluminate-ternesite cement is less than 5 wt .-%, in particular less than 2 wt .-% and most preferably less than 1 wt .-%.

Use according to one of claims 1 to 6, characterized in that in the belite-calcium sulfoaluminate-ternesite cement a X-ray amorphous phase or glass phase in an amount of 1 to

10 wt .-%, preferably 2 to 8 wt .-% and in particular 3 to 5 wt .-% is present.

Process for the production of components and buildings, characterized in that:

providing a belite-calcium sulfoaluminate-ternesite cement,

- mixes the Belit-calcium sulfoaluminate-ternesite cement with aggregate and water to a building material, and

- Forming the building material with a 3D printer in layers to the component or building.

A method according to claim 8, characterized in that as an aggregate sand and / or crushed sand and / or gravel and / or crushed rocks and / or recycled aggregates of natural origin and / or from industrial production with a particle size of up to 32 mm, preferably to used to 8 mm, especially up to 4 mm.

A method according to claim 8 or 9, characterized in that in the building material, a weight ratio of belit-calcium sulfoaluminate ternesite cement to aggregate in the range of 1: 2 to 1: 8, preferably from 1: 3 to 1: 5, is set.

1 1. A method according to any one of claims 8 to 10, characterized in that in the building material, a water / cement value in the range of 0.25 to 0.8, preferably from 0.3 to 0.5, is set.

12. The method according to any one of claims 8 to 11, characterized in that the building material is mixed at least one of clinker replacement material, additive and additive.

13. The method according to claim 12, characterized in that the

Building material Clinker substitute materials such as fly ash, granulated blastfurnace slag and / or microsilica, preferably in a weight ratio of belite-calcium sulfoaluminate-ternesite cement: clinker substitute material in the range of

1: 0.7 to 1: 0.1, in particular from 1: 0.3 to 1: 0.2, are mixed.

14. The method according to claim 12 or 13, characterized in that the building material delaying additives, preferably gluconates,

Fruit acid, phosphates, phosphonates or borates and mixtures thereof and in particular phosphates, phosphonates or borates and mixtures thereof may be added.

15. The method according to any one of claims 12 to 14, characterized in that the building material as an additive fibers, in particular of steel, plastic, glass and / or carbonate, are admixed.

16. The method according to any one of claims 12 to 15, characterized in that the building material as an additive one or more

Concrete pigments and / or photocatalysts are admixed.

17. The method according to any one of claims 8 to 16, characterized in that the belit-calcium sulfoaluminate-ternesite cement by mixing calcium sulfoaluminate cement and ternesite cement obtained by sintering a raw meal from raw materials containing at least CaO and Si0 ₂ bereitsteilen, was obtained at temperatures of 900 to 1300 ° C, is provided.

18. A process according to any one of claims 8 to 16, characterized in that the belite-calcium sulfoaluminate-ternesite cement is provided by grinding a belite-calcium sulfoaluminate-ternesite clinker, wherein the beiite-calcium sulfoaluminate-ternesite clinker is prepared by sintering a raw meal Raw materials providing at least CaO, S1O2 and Al2O3 in a temperature range of> 1200 ° C to 1350 ° C, annealing a clinker intermediate product thereby obtained in a temperature range of 1200 ° C to a lower limit of 750 ° C to the belite calcium sulfoaluminate -Ternesite clinker and cooling of the belite-calcium sulfoaluminate-ternesite-Kiinkers was obtained.