WO2019215139A1

WO2019215139A1 - Ultra-high performance concrete

Info

Publication number: WO2019215139A1
Application number: PCT/EP2019/061665
Authority: WO
Inventors: Stefan Vogt; Ursina JENNY
Original assignee: Baustoffe Schollberg Ag; Kibag Management Ag
Priority date: 2018-05-09
Filing date: 2019-05-07
Publication date: 2019-11-14
Also published as: CH714982A2; CH714982B1

Abstract

The invention relates to a dry mixture for producing an ultra-high solid concrete. The dry mixture comprises aggregate having a CaCO3 content of at least 75 %, a first filler having a grain size of 10 µm to 125 µm, and a second filler having a grain size of 0.7 µm to 10 µm. The first and second fillers have a CaCO3 content of at least 75 %.

Description

Ultra-high performance concrete

Tech nical area

The invention relates to the field of concrete construction, in particular the field of ultra-high-strength concretes. It relates to a dry mix for the production of an ultra-high-strength concrete, a fresh ultra-high-strength concrete, as well as its use in concrete construction, an ultra-high-strength concrete, and a process for its preparation.

State of the art

Ultra-high-performance concrete or ultra-high-strength concrete (UH FB), in contrast to common types of concrete, is characterized by a very high compressive strength of more than 1 20 M Pa. Due to the high compressive strength and strong binding effect of the U H FB fails in a crack around the aggregates around, but is characterized by the fact that cracks pass through them.

Due to its greatly increased pressure resistance, UH FB is particularly suitable for the production of pressure-stressed components, such as columns, columns and walls, in particular high-rise buildings, bridges or tunnels. The beneficial effect of UH FB increases with increasing building height, as more stable support structures with less space are made possible. In addition, the use of UH FB in building construction allows new design and constructive solutions, which are not feasible by other concretes due to the lack of stability. In addition to components subject to pressure, the UH FB is also suitable for the production of bending-stressed components, such as beams or beams of, for example, aluminum. As bridges or oil platforms. Known ultra-high-strength concretes contain not only cement, but also finely ground quartz sand, which is needed to achieve the very high structural density. Furthermore, the ultra high-strength concretes known in the state of the art are characterized by comparatively low water cement values (wz) of 0.3 to 0.2, as a result of which the distance between the individual cement grains is markedly reduced. While the reduction of the water cement value has an advantageous effect on the strength of the concrete, at the same time its processing is made more difficult. For this reason, the fresh ultra-high-strength concrete or the UH FB contains relatively large amounts of flow agent. To avoid brittle fracture failure and increase stability, the ultra high strength concretes may contain fiber materials.

The invention is concerned with the invention

Despite the significant advantages in terms of stability, weight and space requirements compared to the usual types of concrete, no U H FB has yet been able to assert itself as a mass product. One reason for this is the costly production, as well as the relatively high cost of the starting materials, which must be processed separately, processed and stored.

A significant disadvantage of the known ultra-high-strength concretes is the occurrence of the alkali silicic acid reaction. The calcium hydroxide of the cement reacts with the quartz to form various calcium silicates, for example wollastonite. The alkali silicic acid reaction is particularly problematic when the concrete is exposed to moisture and air, since the silicates explode heavily under water absorption, which can lead to cracking in the concrete. In Germany alone, the need for refurbishment of airport runways damaged due to the alkali-silica reaction was estimated in 201 6 at 1 .2 billion euros. It is therefore the object of the invention to further develop the state of the art in the field of ultra-high-strength concretes and preferably to overcome disadvantages of the prior art. In advantageous embodiments, the invention provides a U HFB which has a very high resistance to the alkali silicic acid reaction. In another embodiment, a lower cost UH FB is provided over the prior art.

Another object of the invention is to further develop the state of the art in the field of production methods of U H FB. In advantageous embodiments, a particularly stable and durable UH FB can be provided by a manufacturing method according to the invention.

These objects are solved in a general way by the subject matters of the independent claims.

Further advantageous embodiments will become apparent from the dependent claims, as well as the disclosure as a whole. In a first aspect, the invention relates to a dry blend (the so-called premix) for producing an ultra-high-strength concrete comprising an aggregate having a CaC0 ₃ content of at least 75%. Furthermore, the dry mixture comprises a first filler having a particle size of substantially 1 0 pm to 1 25 pm and a second filler having a particle size of substantially 0.7 pm to 1 0 pm. The first and second filler each have a CaC0 ₃ content of at least 75%. It has been shown that the high CaC0 ₃ content of the aggregate, as well as the first and second filler a particularly dense packing and a particularly strong bond between the particles in the U HFB can be achieved, whereby its strength is further increased. This effect is further enhanced by the use of a first and a second filler with different grain sizes, as a result of vacancies and the formation of pores in the UH FB prepared from the dry mix according to the invention can be avoided. It has been found that a synergistic effect is achieved by the claimed grain size ranges of the first and second fillers, as the first filler efficiently fills the larger voids in the aggregate packing and the second filler fills the smaller voids in the second filler packing ,

The person skilled in the art understands that, as is customary in concrete production, the stated particle sizes are a particle size distribution and thus possibly small fractions of the filler can also be below the stated range. For example, the mean value of the grain size of the second filler is preferably 2 to 6 μm. In addition, the term aggregate is known to the person skilled in the art from the standard EN 1 2620: 201 8, for example.

Typically, at least 75%, in particular 85%, in particular 90%, in particular 95%, preferably substantially 100% of the first filler in a particle size of 1 0 pm to 1 25 pm are present. Typically, at least 75%, in particular 85%, in particular 90%, in particular 95%, preferably substantially 100%, of the second filler may be present in a particle size of from 0.7 μm to 10 μm.

Preferably, the use of quartz sand is dispensed with, whereby a very cost-effective and stable ultrahigh-strength concrete can be obtained by means of a dry mixture according to the invention.

In a further embodiment, a dry mixture according to the invention for producing an ultra-high-strength concrete additionally comprises a binder or an additive, for example cement, lime or fly ash. In some embodiments, the dry blend for making an ultra-high strength concrete additionally comprises a fibrous material. This fiber material may be steel fibers, carbon fibers, mineral fibers, eg. As basalt, plastic fibers, z. B. from polypropylene, textile fibers or glass fibers or mixture thereof.

Typically, the dry mixture additionally comprises microsilica with a particle size of 0.1 μm to 10 μm, preferably 0.1 μm to 5 μm. Typically, commercially available compacted microsilica is used. However, it is alternatively possible to use uncompacted microsilica. The use of microsilica can increase the wear resistance and the service life of the U H FB according to the invention. In a further embodiment, the dry mixture additionally comprises a deaerator, preferably an alkyl phosphate, such as, for example, triisobutyl phosphate, triethyl phosphate or tri-n-butyl phosphate. By using a breather, the air-pore volume in the fresh ultra-high-strength concrete and ultrahigh-strength concrete produced from the dry mix is reduced. The proportion of the deaerator based on the binder 5 is preferably 0.2 to 1%.

In a further embodiment, the aggregate has grain sizes of from 1 25 μm to 2 mm, preferably from 1 25 to 500 μm.

In a preferred embodiment, the aggregate, the first filler and / or the second filler have a CaC0 ₃ content of 75% to 99%, preferably 900 to 99%, particularly preferably 93% to 99%. Preferably, the aggregate, the first filler and / or the second filler is resistant to the alkali silicic acid reaction (alkali aggregate resistant). This resistance can be achieved inter alia by the relatively low silicate and silicate rock content of the aggregate, the first filler and / or the second filler. In particular, by the absence of large quantities of quartz sand, the aggregate is the first filler and / or the second filler resistant to the alkali-silica reaction. The density of the first filler and / or the second filler is typically in a range of 2 to 3 g / cm ³ , preferably between 2.5 and 2.9 g / cm ³ .

In a further embodiment, the aggregate, the first filler and / or the second filler has a pyrite content of at most 0.05%, preferably of at most 0.01%. Furthermore, the sulfur content of the aggregate, the first filler and / or the second filler is below 0.1%.

In advantageous embodiments, the proportion of unsuitable sheet silicates such as mica, kaolinite, chlorite and swellable materials on the aggregate, on the first filler and / or on the second filler is less than 6%. The proportion of swellable minerals is preferably below 0.1%.

In a further embodiment, the aggregate, the first filler and / or the second filler has a silicate rock content of 0.05% to 10%, preferably 0.05% to 5%, particularly preferably 0.05 to 3%. In a preferred embodiment, the binder comprises cement with particle sizes of 0.1 pm to 40 pm.

In a further embodiment, the binder comprises calcium sulfoaluminate or CEM I cement (Portland cement with a maximum of 5% further materials). The proportion of calcium sulfoaluminate in the binder is preferably 50 to 85%, preferably 75 to 85%. In a preferred embodiment, the dry blend for making a UH FB comprises lithium carbonate. By using lithium carbonate, the processing duration and the consistency of the fresh ultra-high-strength concrete produced from the dry mix can be regulated in time. In particular, the solidification of the fresh Ultra-high-strength concrete accelerated. The content of the lithium carbonate is preferably 0.2 to 1%, particularly preferably 0.5%, based on the weight of the binder.

In a further embodiment, the dry mixture for producing a U H FB comprises at least one fruit acid, for example tartaric acid, malic acid or citric acid. 5 These are preferably added to the dry mixture as a 20 to 50% aqueous solution.

It has also been found that the processing time of the fresh ultra-high-strength concrete produced from the dry mix can also be time-regulated by the fruit acid. In particular, this may cause a delay in the start of solidification of the fresh ultra-high-strength concrete. Preferably, the content of the at least one fruit acid is 0.25 to 5%.

In some embodiments, the ratio of aggregate: first filler: second filler in the dry mix may be substantially 8.5: 1: 0.5. As a result, a particularly stable U H FB can be obtained.

In another embodiment, the dry mix additionally comprises hard particles for protection against abrasion of the ultrahigh strength concrete produced from the dry mix. The hard particles are typically made of an abrasion-resistant material, for example corundum or silicon carbide (Lonsicar).

In some embodiments, the dry mix may be comprised of an aggregate having a CaCO ₃ content of at least 75%, a first filler having a grain size of from substantially 10 pm to 1 25 pm, and a second filler having a grain size of from about 0.7 pm to 10 pm exist. Alternatively, the dry mixture may additionally consist of one or more of the abovementioned components, such as binders, fiber material, microsilica, deaerator, lithium carbonate and / or timed acids. Another aspect of the invention relates to a fresh ultrahigh-strength concrete comprising a dry mix according to the invention as described above for producing an ultra-high-strength concrete and water.

In a preferred embodiment, the fresh ultra-high-strength concrete according to FIG. 5 comprises the concrete bulk density [kg / m ³ ]: 29 to 35%, preferably 31 to 33%, aggregate; 0.1 to 7%, preferably 3 to 5%, of the first filler; 0.1 to 5%, preferably 1 to 3%, of the second filler

In further embodiments, the fresh ultra-high-strength concrete comprises, based on the concrete raw density [kg / m ³ ]: 29 to 35%, preferably 31 to 33%, aggregate; From 0.1 to 0.7%, preferably from 3 to 5%, of the first filler; 0.1 to 5%, preferably 1 to 3%, of the second filler and 30 to 41%, preferably 35 to 37%, of binder.

In further embodiments, the fresh ultra-high-strength concrete comprises, based on the concrete raw density [kg / m ³ ]: 29 to 35%, preferably 31 to 33%, aggregate; 0.1 to 7%, preferably 3 to 5%, of the first filler; 0.1 to 5%, preferably 1 to 3%, of the second filler; 30 to 41% preferably 35 to 37%, binder and 5 to 1 7%, preferably 9 to 1 2%, fiber material and 4 to 1 0%, preferably 6 to 9%, water.

Typically, the fresh ultrahigh-strength concrete comprises at least one flow agent comprising in particular acrylic polymers, for example Dynamon NRG 1020 (Mapei), polycarboxylates, polycarboxylate ethers and polycarboxylate esters. Furthermore, the Frisch-0 ultrahigh strength concrete may include at least one deaerator. As deaerators, inter alia, alkyl phosphates, for example triisobutyl phosphate, triethyl phosphate or tri-n-butyl phosphate, can be used. In addition, the fresh ultra-high-strength concrete may have hard particles for protection against abrasion. Another aspect of the invention relates to the use of a fresh ultra-high-strength concrete according to the invention as building material. Typically, the novel ultra-high-strength concrete is used for the production of concrete components, repair or maintenance of concrete structures such as pillars, columns or beams, bridges, drainage systems or channels. The fresh ultra-high-strength concrete according to the invention is additionally used as a building material for traffic routes, such as streets, sidewalks, tracks or airport runways.

Particularly advantageous is the use of fresh ultra-high-strength concrete for the repair and maintenance of bridges, since its use does not significantly alter the statics of the bridge. Typically, the UH FB according to the invention already reaches a compressive strength of more than 1 00 M Pa after two days. Furthermore, the fresh ultra-high-strength concrete can harden very quickly, so that after only 2 hours already a compressive strength of at least 20 M Pa is achieved. Thus, traffic routes, such as a highway bridge, can be repaired quickly without the traffic having to be diverted or jammed for a long time. In further embodiments, the inventive Frisch ultra-high-strength concrete for the production of precast concrete elements, such as stairs, floor or deck slabs used. Furthermore, the fresh ultra high strength concrete can be used in the manufacture of wind turbines. The fresh ultra high strength concrete is typically used as a shotcrete. A further aspect of the invention relates to a process for producing an ultra-high-strength concrete comprising the steps of: a) providing a dry mixture according to the invention and as described above; b) adding water to the dry mixture from step a) and mixing to produce a fresh ultrahigh-strength concrete. The mixing time in step b) is preferably 5 to 15 minutes. Typically, the fresh ultra-high-strength concrete is then used in accordance with the invention, for example via injection molding. Subsequently, in step c) the fresh ultra-high-strength concrete obtained in step b) is dried. optional The fresh ultra-high-strength concrete can be covered to protect it from premature dehydration, mechanical or chemical stress and extreme temperatures.

In a further preferred embodiment, the fresh ultrahigh-strength concrete is smoothed and / or coated. H ebei the fresh ultra-high-strength concrete is preferably coated with a post-treatment product. The aftertreatment product protects the fresh ultra-high-strength concrete from drying out due to heat and wind, thus delaying moisture evaporation on the concrete surface, thereby preventing plastic shrinkage and the formation of cracks. The post-treatment product used is preferably a polymer resin or a mixture of polymer resins. This is preferably present as an aqueous emulsion. For example, the post-treatment product Mapecure E30 (Mapei Suissa SA) or Mapacrete Film 1 4 (Mapei Suisse SA) can be used.

In some preferred embodiments, lithium carbonate can be added to the fresh ultra high strength concrete to adjust the processing time so that the ultra high strength concrete reaches a compressive strength of 20M Pa after only 2 hours.

In preferred embodiments, at least one fruit acid, for example malic acid, tartaric acid or citric acid, may be added to the fresh ultrahigh-strength concrete to adjust the processing time. Preferably, the at least one fruit acid is added as a 20 to 50% aqueous solution.

In further embodiments, the addition of binder (for example calcium sulfonate), hard particles, lithium carbonate, deaerator and / or additionally takes place in step b)

Fiber materials. In a preferred embodiment, in step b) first the water and the binder are added and mixed, preferably for 2 to 15 minutes. Thereafter, the fiber material is added, followed by mixing, preferably for 5 to 10 minutes. The mixing time should not last longer than 20 minutes, as otherwise forms a very unfavorable cement matrix.

Typically, the addition of the fiber material is slow, continuous and with stirring. Particularly preferably, the fiber material is added only after the addition of the binder and mixing. In some embodiments, the fiber materials are already included in the dry mix according to the invention and thus need not be added in an additional step. The addition of the fiber materials to the dry mixture according to the invention can be carried out preferably by means of suitable fiber dosing systems.

After the use of fresh ultrahigh-strength concrete, for example as shotcrete or for repair, this is typically dried. Another aspect of the invention relates to an ultra-high-strength concrete obtainable by an embodiment of the method according to the invention. The U FH FB according to the invention preferably has a compressive strength of at least 20 M Pa after 2 hours.

In preferred embodiments, the inventive ultra high-strength concrete according to the fire protection regulations BSV 21 05 meets the group RF1 and thus provides no fire contribution. Another aspect of the invention relates to a set of parts comprising a dry mixture according to the invention and hard particles as described above. The hard particles are typically made of an abrasion-resistant material, for example corundum or silicon carbide (Lonsicar) and are preferably applied to the fresh mixture produced from the dry mixture. Ultra-high-strength concrete applied. This can typically be done by sprinkling and pressing.

In a preferred embodiment, the set of parts comprises a dry mix according to the invention as described above and an after-treatment product, preferably 5 polymer resins, which are typically present as an aqueous emulsion. Optionally, the kit of parts can additionally comprise hard particles.

Brief explanation of the figure

With reference to the following embodiments and the figures aspects of the invention will be explained in more detail. 1 shows a sieve-line analysis of a first filler according to the invention

Embodiment of the invention;

FIG. 2 shows a sieve-line analysis of a second filler according to the invention of a further embodiment of the invention; FIG.

Fig. 3 is a sieve-line analysis of an aggregate according to the invention of another embodiment of the invention; and

4 shows a sieve-line analysis of a cement according to the invention of another

Embodiment of the invention. Ways to carry out the invention

Listed below are some examples of formulations for dry blends according to the invention for the production of an ultra-high-strength concrete, as well as for a fresh ultra-high-strength concrete. Example 1a: Dry mixture for the production of an ultra-high-strength concrete

Component in kg Comment

Particle size 125 to 500 pm,

Aggregate 835

according to FIG. 3

Particle size 10 to 125 pm, according to

First filler 120

FIG. 1

Particle size 0.7 to 10 pm, according to

Second filler 40

FIG. 2

Mapeplast SF (manufacturer: Mapei),

Microsilica 143

Particle size 0.1 pm to 5 pm

Example 1b: Fresh ultrahigh-strength concrete

Component in kg Comment

Particle size 125 to 500 pm (FIG

Aggregate 835

3)

First filler 120 Particle size 10 to 125 μm (FIG. 1) Second filler 40 Particle size 0.7 to 10 μm (FIG. 2)

Mapeplast SF (manufacturer: Mapei),

Microsilica 143

Particle size 0.1 pm to 5 pm

CEM I 52.5 R (LafargeHolcim Werk

Zement 940 Dotternhausen), particle size 0.1 pm to 40 pm (FIG. 4)

Diameter smaller 0.20 mm,

Steel fiber 280

Fiber length less than 13 mm

Dynamon NRG 1020 (Manufacturer:

Flow agent 37.6

Mapei)

Water 195

Example 2a: Dry mixture for the production of an ultra-high-strength concrete

Component in kg Comment

Particle size 125 to 500 pm (FIG

Aggregate 763

3)

First filler 135 Particle size 10 to 125 μm (FIG. 1)

Second filler 50 Particle size 0.7 to 10 pm (FIG. 2)

Mapeplast SF (manufacturer: Mapei),

Microsilica 175

Particle size 0.1 pm to 5 pm Example 2b: Fresh ultra high strength concrete

Component in kg Comment

Particle size 1 25 to 500 pm (FIG

Aggregate 763

3)

First filler 1 35 Particle size 1 0 to 1 25 μm (FIG. 1) Second filler 50 Particle size 0.7 to 10 μm (FIG. 2)

Mapeplast SF (manufacturer: Mapei),

Microsilica 1 75

Particle size 0.1 pm to 5 pm

CEM I 52.5 R (LafargeHolcim Werk

Zement 940 Dotternhausen), particle size 0.1 pm to 40 pm (FIG. 4)

Diameter smaller 0.20 mm,

Steel fiber 280

Fiber length less than 1 3 mm

Dynamon N RG 1 020 (Manufacturer:

Flow agent 42.3

Mapei)

Triisobutyl phosphate (ENTLÜ FTER - RCT

Breather 4.7

GmbH )

Water 201

To prepare a fresh ultrahigh-strength concrete according to Example 2a, the following procedure can be followed: In a first step, the aggregate, the first and second filler, the microsilica can be weighed and mixed for 30 seconds dry mixing time. In a further step, the cement and water are then added during a continuous mixing. After mixing for 5 to 15 minutes, the steel fibers are added slowly, continuously and with stirring. Alternatively, as described above, the fibers may already be included in the dry blend. After a Mixing time of 5 to 1 0 minutes, the manufactured fresh ultra-high-strength concrete can be used.

In the production of fresh ultrahigh-strength concrete, the mixed water is usually completely consumed, so that no communicating Kapillarporen can form and the water from the outside is negligible.

In the above examples, the aggregate, the first filler and / or the second filler has a CaC0 ₃ content of 95 to 99%.

Claims

Patent claims

1 . A dry blend for producing an ultra high strength concrete comprising:

Aggregate with a CaC0 ₃ content of at least 75%;

a first filler having a grain size of 1 gm to 1 25 gm and a second filler having a grain size of 0.7 gm to 1 0 gm, wherein the first and second filler have a CaC0 ₃ content of at least 75%.

2. Dry mixture according to claim 1 comprising a binder, a fiber material, a deaerator and / or microsilica with a particle size of 0.1 gm to 1 0 gm, preferably 0.1 gm to 5 gm.

3. Dry mixture according to one of the preceding claims, wherein the aggregate

Grain sizes from 1 25 gm to 2 mm, preferably 1 25 to 500 gm having.

4. Dry mixture according to one of the preceding claims, wherein the aggregate, the first filler and / or the second filler have a CaC0 ₃ content of 75% to 99%, preferably 90 to 99%.

5. Dry mixture according to one of the preceding claims, wherein the aggregate, the first filler and / or the second filler have a maximum pyrite content of 0.05%, preferably of at most 0.01%.

6. Dry mixture according to one of the preceding claims, wherein the aggregate, the first filler and / or the second filler have a silicate rock content of 0.05% to 1 0%, preferably 0.05% to 5%.

7. Dry mixture according to one of claims 2 to 6, wherein the fiber material comprises steel fibers, carbon fibers, glass fibers, plastic fibers and / or textile fibers.

8. Dry mixture according to one of claims 2 to 7, wherein the binder cement,

5, preferably calcium sulfoaluminate or CEM I cement.

A dry mix according to claim 8, wherein the cement has grain sizes of 0.1 μm to 40 μm.

1 0. Dry mixture according to one of the preceding claims additionally comprising lithium carbonate and / or at least one fruit acid. 0 1 1. A dry mix according to any one of the preceding claims, wherein the ratio

Aggregate: first filler: second filler is essentially 8.5: 1: 0.5.

1 2. Dry mixture according to one of the preceding claims, wherein the dry mixture additionally comprises hard particles. 5

1 3. Fresh ultra high strength concrete comprising an ultra high strength concrete composition according to any one of the preceding claims and water.

1 4. Fresh ultra high strength concrete according to claim 1 3, comprising

29 to 35%, preferably 31 to 33%, aggregate;

0.1 to 7%, preferably 3 to 5%, of the first filler;

0 0.1 to 5%, preferably 1 to 3%, of the second filler;

30 to 41%, preferably 35 to 37%, binder;

5 to 1 7%, preferably 9 to 1 2%, fiber material; and 4 to 10%, preferably 6 to 9% water.

1 5. fresh ultra-high-strength concrete according to claim 1 3 or 1 4 additionally comprising

Hard particles, a flow agent and / or a deaerator.

1 6. Use of the fresh ultra-high-strength concrete according to one of claims 1 3 to 1 5 as a building material, in particular for the production, repair or maintenance of concrete components, concrete structures, bridges, traffic routes, channels, buildings and tracks.

A method for producing an ultrahigh-strength concrete, comprising the steps of: a) providing a dry mix according to any one of claims 1 to 12; b) adding water to the dry mixture and optionally adding binder, lithium carbonate, at least one fruit acid, hard particles, deaerator and / or fiber materials; and blending to produce a fresh ultra-high strength concrete; c) drying.

1 8. The method of claim 1 7, wherein the fresh ultra-high-strength concrete produced in step b) is smoothed and / or coated with an aftertreatment product.

1 9. Ultra high strength concrete obtainable by the process according to claims 1-7 or 1-8.

20. Ultra-high-strength concrete according to claim 1 9 wherein the concrete after 2 hours has a compressive strength of at least 20 M Pa.

21. Parts set comprising a dry mix according to any one of claims 1 to 1 2 and

Hard particles and / or an aftertreatment product.