FI123552B - Structured binder composition - Google Patents

Description

Structured binder composition

The present invention relates to a structured granular binder composition suitable for the preparation of a concrete mass and a concrete or mortar mass containing a granular composition.

The invention also relates to processes for preparing a granular composition and a concrete or mortar mass.

Concrete is a multi-constituent material whose properties are constantly changing. There are many factors that influence the behavior and properties of concrete, such as changes in humidity and temperature, carbon dioxide content in the air, etc. There is a strong relationship between changes in the moisture content of concrete and its mechanical properties such as strength, shrinkage, fading and elastic modulus. Water, or moisture, is an essential part of old, even hardened concrete.

15 The active ingredient of a concrete, that is, a cured binder, or cement stone, consists of small components of variable shape which are joined together, except by chemical bonding, mainly by physical action, and by small pores filled with water molecules between these components. Such a porous and hygroscopic material with a huge internal surface area (about 200 m2 / g) is sensitive to external influences and undergoes constant structural changes.

Due to these structural changes due to time, ambient temperature and humidity, cement and concrete made from it are difficult to determine. However, most common binders, such as cement, have in common that they are water-hardening and such binders are called hydraulic binders. In this context, we are talking about the granular binder composition and the accompanying and further events of the hydration to which the invention relates. The most typical such hydraulic binder is Portland cement, the main components of which are tricalcium silicate (C3S, 54% in cement chemistry), dicalcium silicate (C2S, 17%), tricalcium aluminate (C3A, 10%) and tetracalcium aluminum σ "" 30 ferrite (C4AF, 10%). The latter two are essentially only clinker formers which do not play a major role in the strength provided by the binder.

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C3S releases 3 moles of Ca (OH) 2 when hydrated, and C2S releases 1 mole of calcium hydroxide, respectively. The fastest cured is C3A, which requires 6 to 2 moles of water to hydrate, as well as C4AF. Initially, the compressive strength of the binder develops mainly from C3S hydration and over a long period (> 90 days) of C2S hydration, which achieves the same final strength as the C3S hydration product, eventually over the same time period of about one year at normal temperature. The theoretical water / cement ratio (w / c ratio) where all water would be moistened for hydration would be 0.245 with the composition described above. In practice, however, the water / cement ratio is higher so-called. gel water, which is about 18%. The water then penetrates into the pores at about 2 nm. This water, which is slowly consumed for hydration, causes shrinkage in the concrete mass, as well as carbonization of released Ca (OH) 2.

10

When making concrete, it is also possible to achieve bond strength by means of side reactions other than those mentioned above. by reaction of clinker minerals and water. The pozzolanic reaction is called when the silicate mineral reacts with lime and water, thus binding the lime rather than releasing it, as happens in the C3S and C2S reactions. The pozzolanic reaction is essentially the reaction of calcium hydroxide [in cement (CH)], silica, S1O2 (S), and water (H) to form CSH as well as CAH and CASH depending on the pozzolanic material. When heat treated at 500-850 ° C, kaolin loses its crystalline water and produces Al 2 O 3 · S 1 O 2, which is pozzolanically active in water. The product is called metakaolin. Metakaolin is sold by several companies and has been researched to be more effective at increasing strength than microsilica while being more effective at compacting concrete, etc.

Previously, U.S. Patent 5,788,762 to Ash Grove Cement Company has patented the use of meta-kaolin as a pozzolan in cement such that after burning, meta-kaolin has been milled to such an extent that the water / binder ratio to be worked is less than or equal to 0.33.

g This means that metakaolin cannot be further refined because the water requirement increases significantly.

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In addition to the aforementioned methods of achieving bond strength, a third way to achieve bond-σί 30 strength in a mineral binder is to allow small particles to crystallize by crystallizing gi is the surface energy of the particle, meaning that small particles always try to grow larger .

o get bigger. This Gibbs Law Σ a; g; - »minimum, where ai is the particle surface area and

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3

The problem with concrete production has been the mixing technique, which aims to mix a homogeneous mixture of fine binder particles and coarse aggregate. The binder-perticles are then easily adhered to each other and form agglomerates, which cause the concrete to deteriorate.

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The crux of the problem is that the fines require a mixing energy of 1-6 kWh / t and the coarse parts only 0.3-0.5 kWh / t.

Equipment that efficiently mixes fines at the required 10-bar power for 1-2 minutes requires more power than is needed to mix all the concrete. Therefore, a kind of compromise has been used in the mixing of concrete, which is used at the expense of product quality.

It is an object of the present invention to provide a composition suitable for making concrete or mortar masses which utilizes several different strength-giving mechanisms at the same time, while still being able to keep mixing this mass simple.

Surprisingly, it has been found that high strength can be achieved by using preformed binder granules (prior to 20 concrete production), thereby reducing the surface energy of the various components of the composition.

The present invention thus relates to a granular composition for the preparation of a concrete mass and a concrete or mortar mass made therefrom.

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More specifically, the composition of the present invention is characterized by what is set forth in the characterizing part of claim 1.

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The process for preparing the composition according to the invention, in turn, is characterized by what is claimed in claim 8, the concrete or mortar according to the invention is characterized by what is claimed in claim 12, and the process for preparing concrete or mortar is characterized by is disclosed in claim 14.

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Further, the apparatus for preparing the granule composition according to the invention is characterized in what is claimed in claim 17.

By means of the present invention, the fines of concrete can be transferred to the mortar 5 of the concrete to form a homogeneous binder portion. This is done by introducing the premixed fines into the aggregate in the correct proportions, in relatively large granules, and not milled, as in the Ash Grove Cement Company patent, whereby the need for mixing water does not increase much due to high fines and in turn viscosity. In this way, the nature of the concrete mix is changed into a homogeneous mix between these granules and the aggregate, with a mixer power of 0.3 kWh / h.

The effects of the invention are quite wide. It has the potential, among other things, of using modern mixing equipment for concrete plants to achieve homogeneous mixing of fine particles of concrete as well as successful placement of nanoscale calcium carbonate particles between hydraulic binder particles, thereby affecting the resulting hydrate structure, consolidation.

Figure 1 illustrates an apparatus suitable for preparing a preferred granule composition of the present invention.

The present invention thus relates to a granular composition for the preparation of a concrete mass consisting of granules each containing a metakaolin sinter as a pozzolanic binder, wherein the pozzolanically reactive portion is metakaolin present in the sinter 10 to 80% and fil-eo 0 25 1 different particles having hydraulic binder particles.

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The invention also relates to a concrete or mortar mass which, in addition to this granular composition, contains 1 fine aggregate and a coarse aggregate.

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h- σ> 30 According to a preferred embodiment, the concrete consists of a mortar part, i.e. a binder part, and a frame part, the binder part preferably comprising: - a hydraulic binder, e.g. Portland cement (OPC), preferably containing C3A and C4AF parts, - a filler, i.e. a filler, preferably of limestone or SiCL, a pozzolanic binder, preferably of the metakaolin sinter (MKS), in which the pososolane reacting portion is metakaolin present in the sinter 10 to 80%, calcium carbonate as nanoscale particles ( nano), a plasticizer, typically a polymer of acrylic acid, and 5-water, which is preferably normal industrial water or treated water [containing e.g. Ca (OH) 2 + 2CO 2 → Ca (HC 3 O) 2], and a builder preferably comprising the following components: - fine aggregate (average particle size <6 mm), preferably 10 limestone, preferably form crushed limestone Or SiO stone of, preferably minced or natural stone, and coarse aggregate (average particle size of 4-16 mm, the largest particles up to 32 mm), preferably, with aggregates SiO, Si02, natural stone, lime, limestone or kikivimursketta so-called extraction. waste rock.

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According to a preferred embodiment, the aggregate comprises 50-85% by weight of fine aggregate, more preferably 70-75% by weight, and 15-50% by weight of coarse aggregate, more preferably 25-30% by weight.

According to the present invention, the concrete components are grouped in a new way prior to mixing the concrete by forming granules according to one of the following alternatives:

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Core bodies are formed from the filler particles, and to these core bodies, first, the calcium carbonate particles with a plasticizer attached thereto are added, followed by a hydraulic binder.

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A granule is formed from the filler and the hydraulic binder, which mainly consists of a core of filler particle-r · »· σ> 30 coils, with a plasterer on its surface, and around which particles of the hydraulic binder are fixed. This granulate is then bonded with 00 calcium carbonate particles (<800 nm in size).

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Rae 3 (special case for granule 2):

A granulate of limestone filler and hydraulic binder is formed, consisting mainly of a limestone filler core with a binder attached to the surface, and the binder particles are attached to this core block by means of the C3A meta-product, 5 Al (OH) 3, and limestone hydrate.

The concrete, in turn, is mixed by adding the following ingredients in said order: 1. granule 2. water or treated water containing Ca (HCO 3) 2, the Ca (HCO 3) 2 in the treated water preferably being about 10 g / l 3. fine aggregate 4. coarse aggregate 5. metakaolin sinter 15 At the beginning of the mixing, a large amount of water is used because the fines of the binder composition are bound to the surface of the microfiller. In this way, fine and coarse aggregates are well watered. At a later stage of the mixing, the water removes the binder particles from the surface of the microfiller and awakens the dry state bulking agent with carrier (calcium carbonate or filler). The plasticizer and the carrier compensate for the water bound by the binder and keep the concrete hel-20 postable for processing.

The cement particles in the granules have an average diameter of about 12 μιη. Correspondingly, the nanoparticles have an average diameter of 50 to 800 nm, preferably 100 to 500 nm, most preferably 100 to 200 nm, and the microfiller has an average diameter of <100 μιη, preferably about 10-40 μιη. These components provide a granule having an average diameter of <300 µm, preferably 20-60 µm, most preferably 20-40 µm.

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According to a particularly preferred embodiment of the invention, the granule composition is prepared by:

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that the projected areas of the hydraulic binder and the calcium carbonate particles are equal to or less than the area of the filler particles of the granules.

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The outermost layer of the surface of the granules preferably consists mainly of cement particles in which C3A has reacted slightly after drying. After formation, the gas retains gas, which, depending on the method of formation, is air, helium or carbon dioxide. The amount of gas is 0.8 - 1.2 dm3 / kg of granule.

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Adhesion of cementitious particles to the surface of limestone particles occurs by utilizing the rapid hydration of CsA in the binder granule. This hydration time remains constant for a period of time from 6 min to 1 h. In this case, the surface-wetted limestone particles together with the Al (OH) 2 binder particle C3A metastable product form a hydrate that binds the binder particle to the limestone particle surface. By drying the resulting product, a granulate is obtained which is preferably miscible with the concrete as a binder. The microfiller-10 binder granule continues to hydrate as water enters the concrete. Surprising is the rapid hydration of the granulate so produced, which is faster than if the various components of the binder composition were added separately to the concrete.

The CaCCbnano particles contained in the granules improve the workability and thereby reduce the need for water in the machining process and further reduce the so-called. formation of capillary pores, which increases the frost, fire and corrosion resistance of the concrete.

The flexibility of the invention can be adjusted by introducing the concrete into the concrete at the final stage of mixing (but before pouring the concrete), a metakaolin sinter powder, which absorbs moving water in the mix and thus acts as a reservoir of water as the hydration progresses.

Adding filler and hydraulic binder to concrete mix in one granule affects the amount of mortar required and can thus use more filler without increasing the water / binder (w / c) ratio, co δ 25 c \ j The use of filler aims to influence this w / c ratio the target value is 0.4: i C \ lo X w _ w

c cred + kF

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CO in o 30 where: ^ won amount of water, c is amount of cement, Cred is amount of cement with effect of filler amount, F is amount of filler and k is coefficient showing effect of filler amount on amount of cement and water (where quantities are expressed by weight). The target value for factor k is 0,25.

The target value is fulfilled, for example, in the case where: 5 * _ 100 k8 _ 100 kg = 0 ^ c 200 kg + 0.25 x 200 kg 250 kg This ratio, in particular the c value of the cement, can be influenced by, inter alia, regulating the amount of binder, hydrate and filler relationship and their quantities, mixability and workability. By adjusting other amounts and ratios, it is also possible to save on the amount of cement, or binder.

When the aforementioned w / c ratio is within the target of 0.4, the space between the particles of the hydraulic binder is about 700 nm in diameter. The nanoparticles of calcium carbonate 15 must fit into this space, where they partially hydrate and reduce the volume that water in the prior art concrete fills. For this reason, the nanoparticles are preferably of average diameter <200 nm. These nanoparticles, when treated with a extender, suppress the binder composition.

20 Dry shrinkage is a common problem in concrete, which impairs the quality of the final concrete. It is caused by the gel water and capillary water trapped between the particles in the concrete. The overall drying shrinkage value is 0.6% o. However, in order to overcome the disadvantages caused by the shrinkage shrinkage in concrete, the shrinkage shrinkage should be:

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o less than the elongation at break of a concrete with an overall value of about 0.2 to 0.3% o. During drying, the shrinkage is reduced in the present invention by introducing finer particles, such as microfillers, between the coarse particles of concrete.

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Granules containing limestone filler and hydraulic binder σ> trapped between concrete aggregate particles increase the volume occupied by the binder composition between aggregate particles o 30. As the binder cures, this reduces the deformation of the formed hydrate, which, among other things, causes the aforementioned drying shrinkage.

The amount of microfiller required and the particle size are affected by the size of the space between the aggregate, which is further influenced by the particle size of the aggregate. As a result, a preferred filter is one whose particles have an average diameter of 10 to 40 µm.

9 5 In the preparation of the preferred granular composition, the amounts of material to be added may be of the following order:% by weight typical example hydraulic binder 30 - 50 250 kg filled 20 - 40 200 kg 10 water 10-20 100 kg calcium carbonate 1-5 20 kg MKS 3-5 38 kg

The present invention also relates to apparatus for preparing granules of the granule composition of the invention. Preferably, the apparatus comprises the following components (Fig. 1): 1 first container 2 cyclone separator 3 pressure roller 20 4 anti-rotor diffuser 5 second container 6 coating apparatus 7 mixing apparatus 8 storage tank co 0 25

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uo According to this preferred embodiment, the apparatus thus includes a first container 1,

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g cyclone separator 2 disposed downstream of first container 1, pressure roller 3, x fixed to the bottom of cyclone separator 2, countercurrent rotor diffuser 4 which is Q.

respectively, mounted on pressure roller 3, a coating apparatus 6 communicating with the upper part of a pulley separator 2 with a second tank 5 connected thereto, a mixing apparatus 7 located o downstream of the coating apparatus 6, and a storage tank 8 located downstream 00 mixing equipment 7.

This granulating device preferably operates in such a way that the material required for the granule, such as a hydraulic binder, can be fed from the first container 1 to the cyclone separator 2. In this separator 2, fine particles are separated from coarse particles. The coarse particles, preferably> 15 µm in size, are comminuted by feeding them through the bottom part 5 of the separator 2 first through a pressure roller 3 and then through a counter-rotor diffuser 4, then being combined with the partially bonded particle separator The fine particles separated from the coarse particles, preferably <15 µm in size, are in turn passed through the top of the separator 2 to the coating apparatus 6, where they are mixed with a feed from the coating apparatus 6, preferably containing a microfiller from the second container 5. coated with calcium carbonate to which a plasticizer is attached. Thus, the coated materials are fed from the coating apparatus 6 to the mixing apparatus 7, where the microfiller-calcium carbonate particles are mixed with the binder particles, whereupon the granules formed 15 are led to a storage container 8 for storage before use.

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Claims (17)

1. Granule composition for the manufacture of concrete or concrete pulp, characterized in that it consists of granules each containing metakaolin as pozzolant binder, the pozzolant reacting part being metakaolin present in 10 to 80% in the sinter, and filler particles, at whose surface the particles of a hydraulic binder are attached. Composition according to claim 1, characterized in that calcium carbonate particles are attached to the surface of the filler particles, the surface of which plasticizer is in turn attached, the hydraulic binder particles being attached to the filler particles via the calcium carbonate softener particles. Granule composition according to claim 1, characterized in that the binder particles are attached to the filler particles by means of the binder CaA meta product, Al (OH) 3, and the hydration product of the limestone. Granule composition according to any of the preceding claims, characterized in that the diameter of the granules ranges from 10 to 100 µm, preferably to 20 to 40 µm, and they are spherical. Granule composition according to any of the preceding claims, characterized in that its granules contain o w - a hydraulic binder, such as Portland cement (OPC), uo 20. a filler, i.e. a filler, which is preferably limestone or S1O2-c \ j Stone, £ - a pozzolant binder made of metakaolin sinter (MKS), wherein the pozzolant reacting portion is metakaolin, and - calcium carbonate in the form of nano-sized particles (CaCCFnano), a plasticizer typically comprised of a acrylic acid polymer, and - the water, which preferably consists of industrial water or treated the water containing Ca (HCO 3) 2. Composition according to any of the preceding claims, characterized in that the pozzolanic binder consists of kaolinite-containing calcined clay or a form thereof, called kaolin, and that the pozzolant-reacting moiety is metakaolin present in this binder 10-80%. . Composition according to claim 5 or 6, characterized in that the projection surfaces of the hydraulic binder and calcium carbonate particles are equal in size to or smaller than the surfaces of the filler particles of the granules. Process for preparing a granule composition according to any one of claims 1-7, characterized in that at the surface of calcium carbonate particles, plasticizers are first attached, after which the formed calcium carbonate plasticizers particles are attached to the surface of filler particles, and finally a hydraulic binder is attached to the surface. filler particles via calcium carbonate plasticizer particles. Method according to claim 8, characterized in that the composition is added to pozzolant binder. 15 Process according to claim 8 or 9, characterized in that the particles of the binder are coated with calcium carbonate particles before they are attached to the filler particles, after which these calcium carbonate particles are coated with plasticizer. co Method according to claim 8 or 9, characterized in that the binder particles and cvJ are attached to the filler particles by means of the binder CsA meta product, Al (OH) 3, and LO cp 20 the hydration product of the limestone. cm o ϊ 12. Concrete or concrete pulp, characterized in that it contains a granular aggregate. composition according to any of claims 1-7 as well as gravel material and coarse stone material. CM σ> LO § 13. Mass according to claim 12, characterized in that the gravel material is made of limestone CM Stone, preferably crushed limestone, or SiO2 stone, preferably crushed or natural stone, and the coarse stone material is SiCV crusher, SiCV natural stone, limestone crusher or s. side stone from limestone quarry. Process for the manufacture of concrete or mortar, characterized in that a granular composition prepared according to any of claims 8-12 is applied to gravel material and coarse stone material. 15. A method according to claim 14, characterized in that the gravel material is supplied as limestone, preferably as crushed limestone, or as Sifvsten, preferably as crush or natural stone, and the coarse stone material is supplied as SiO2 crusher, S1O2 natural stone, limestone crusher or so-called. side stone from limestone quarry. 10 Method according to claim 14 or 15, characterized in that the pulp is added to pozzolant binder. Device for producing a granule composition according to any of claims 1-7, characterized in that it contains a first container (1) for hydraulic binder, a cyclone separator (2) arranged downstream from the first container (1). and intended for separation of fine portions clear from coarse portions clear, - a pressure roller (3) attached to the bottom portion of the cyclone separator (2), an impeller rotor distributor (4) similarly attached to the pressure roller $ 2 (3) , which are intended for atomizing the coarse particles, a coating device (6) which communicates with the upper portion of the cyclone separator (2) LO S5 and to which a second filler container (5) is connected, which C Coating device is intended for coating the film, X £ - a mixing device (7) arranged downstream of the coating device (6) and intended for mixing of adhesive and a σ> S 25 coated filler, and o - a storage container (8) disposed downstream from the mixing device (7).