HU212386B - Hydraulic binder for concrete or mortar - Google Patents

Description

The present invention relates to a hydraulic binder for concrete or mortar. The hydraulic binder of the present invention is particularly applicable to concrete or mortar to be processed by the dry or wet injection process and contains commercially available cement (e.g. pumice-portland cement, blast furnace slag cement) and optionally additives and includes fine cement and / or fine clinker.

The binder of the present invention is particularly applicable to aerated concrete or mortar for the production of environmentally friendly aerated concrete by any of the firing methods (dry and wet process). In general, the binder of the present invention may be used in all applications where rapid solidification and high strength are achieved in a short period of time. In addition to aerated concrete and mortar, another example is the use of the finished concrete product in the industry, in the manufacture of cement-bonded fibreboards and in the production of concrete pipes.

The shotcrete is called so-called. In the "new Austrian tunnel construction method", it is installed using the wet and dry process; aerated concrete is one of the most important supporting materials. When the proper compressive strength and layer thickness are achieved, the exposed concrete layer is statically suitable for the final design of the tunnel construction. During the dry process, the dried aggregate is mixed with the cement or transported in the form of a ready-mixed mixture to the construction site and water is added only to the nozzle. The desired rapid solidification is achieved by adding a (liquid) solidification accelerator to the nozzle or by mixing a powder accelerator into the cement / aggregate mixture.

In the wet process, the cement is premixed with wet aggregates and water, then transported to the construction site and applied to the nozzle using a special pump. A hardener accelerator (EB) is mixed on the nozzle and the concrete hardens quickly.

The hardening accelerators currently used consist mainly of alkali metal hydroxides, alkali metal aluminates, alkali metal carbonates and / or water-soluble alkali metal silicates. These hardening accelerators are highly alkaline materials and, when used with care, can lead to significant health damage (dangerous nozzle injuries to persons handling or pre-treating the nozzle). In addition, solidification accelerators must not enter either the groundwater or the receiving equipment. In addition, curing accelerators have a very unfavorable effect on the further development of the strength of the concrete, since the rapid solidification results in the formation of very porous concrete.

A further problem with the application of aerated concrete is the so-called. We refer to “reflection”. The concrete is partially reflected from the wall or roof when applied under pressure. This process changes the composition of the concrete mix, on the one hand, and the reflected material, for example. it must be removed from the tunnel as construction debris. Since the added curing accelerator increases the alkali content compared to conventional concrete, this product is considered a special waste. In addition, reflection significantly increases the material requirement of the launching operation. A significantly longer application time is required to achieve a predetermined (desired) film thickness, and thus health risks are significantly longer for the operator.

Aerated concrete is the outermost layer of the tunnel relative to the bedrock and therefore very often comes into contact with water. Depending on the amount and chemical properties of the water, components may leach from the cracked concrete. This process is greatly facilitated by the aforementioned porous concrete structure produced by cure accelerators. The alkaline substances added as accelerators are primarily responsible for the high pH of the effluent. Under no circumstances should this contaminated water enter the groundwater (drinking water) or damage the drainage system (leaks, further leaching).

Attempts to solve the above problems have been described in the literature. so e.g. AT-B 382 859; In Austrian patent 2000-2008 cm ² / g of Blaine-specific calcium-sulfate-free cement (i.e. for gypsum without gypsum) is proposed for the production of aerated concrete.

The ground clinker hardens directly with the addition of water (fast setting cement), so no curing accelerator is required. However, a major disadvantage is that only fully dried additives can be used. No. AT-B 382 859. The method according to the Austrian patent is therefore limited to dry concrete. A further disadvantage of fast setting cements is that they exhibit a particularly poor strength. In addition, AT-B 382 859 is incorporated herein by reference. It has very low resistance to the action of cement sulfates prepared according to Austrian patent application. The initially formed calcium aluminum hydrate (C ₄ AH ₆ ) is converted to ettringite by secondary reaction transitions. This phase transition leads to a strong volume increase and thus "bending effects".

DE-B 1 800 103. German Patent Application Laid-Open and U.S. Pat. No. 4,405,372. U.S. Pat. No. 4,123,197 and other U.S. patents cited therein also use gypsum-free combs in the presence of small amounts of other binder retardants (e.g., methylcellulose, amine formate or amine acetate) and lime.

JP-A 5,098,514. In order to achieve the properties defined in Japanese Patent Application, Portland cement is mixed with quick-setting cement and high-strength cement in a short period of time. "Fast setting cement" is a product containing sodium gluconate and sodium carbonate. These products are environmentally harmful. JP-A 5,098,514. According to Japanese Patent Application, a PZ 475 cement [Blaine specific surface area of 5300 cm ² / g] is used as Portland cement, not a microcement.

HU 212 386 Β

JP-A 60 180 944. According to the Japanese Patent Application, a standard cement is mixed with up to 40% extrafine cement (Blaine's specific surface area> 6000 cm ² / g, preferably 9000 cm ² / g) to form fast-setting concrete bodies and mixed with <30% water. Particularly fast-setting cement / fine cement mixtures are used in the process. JP-A 60 180 944. however, the high reactivity of microcement to extremely rapid solidification is neither mentioned nor used in Japanese Patent Application, which is more important than high strength for use as shotcrete or mortar.

JP-A 58 223 652. In Japanese Patent Application, the use of a mixture of standard Portland cement with micro-silicic acid and a "calcium expanding agent" is suggested. The latter material has a very high content of CaO (free lime) and CaF ₂ and shows a clinker phase characteristic of certain instant cements (IICaO-7Al ₂ O ₃ CaF ₂ ) Microcement is not mentioned. No particularly fine hydraulic phase is used. JP-A 58 223 652. The mortar obtained according to Japanese Patent Application Laid-Open is used as a filler in the construction of concrete structures.

DE-A-3 503 358. German Patent Application Publication No. 2,968,121 discloses a binder mixture consisting of Portland cement, aluminate cement, limestone and limestone hydrate, and the addition of concrete curing agents and curing accelerators. The use of such mixtures should be avoided for environmental reasons as the curing accelerators used (water glass or similar materials) are harmful to the environment. In addition, the aluminate cement added as a cure accelerator shows known disadvantages (lower strength, low final strength) of such blends.

DE-A 2,055,120. German Patent Application teaches that cement is added to the nozzle as a powder accelerator, but this is not a satisfactory solution in terms of acceleration of solidification. In the German publication cited above, it is proposed to add sprinkler-ground clinker.

DE-B-2 341 493. In German Patent No. 4,198, a mixture of a standard Portland cement with a special calcium aluminate cement is disclosed. However, the bond accelerating component is not based on a high grinding degree, but also to the C] _{2 7} unique properties.

DE-B 1 211 097; German Patent No. 4,198,125 describes a mixture of Portland cement, clay slag cement and anhydrite. However, the special properties are not based on the high grinding fineness and reactivity of part of the binder mixture, but on the blending of the aluminate cement.

DE-A-2 518 799; According to German Patent Application, a slurry or concrete mixture is added directly to the nozzle to the aluminate cement and / or the calcium halide aluminate cement and thereby obtain a rapid solidification.

GB 2,017,673. British Patent Specification discloses hydraulic cements which can be converted into mortar for patching or repairing surfaces damaged by the addition of water. The fine cement described in the disclosure may be a Portland cement. Values for specific surface area are below the range defined in this patent.

EP-A 307 066 is incorporated herein by reference. European Patent Application Publication No. 1, 2000, discloses a dry process for making mortar or cement. In the process, the binder mixture is pneumatically fed to a nozzle where water is added. The publication discloses in particular the use of finely divided silica, which does not involve hydraulic activity. The present patent application relates to the use of a hydraulic binder (fine cement / fine clinker) rather than silica. In addition, the specific surface values reported in said European Patent Application are clearly higher than the range given in this patent.

GB-A 2,139,208. The hydraulic binder described in British Patent Application is a cement clinker ground without gypsum additive. The binder contains 0.01-10% by weight of a salt of a sulfomethylated condensation product made from phenols and formaldehyde. The disclosure does not teach any person skilled in the art the range of specific surface area claimed in this patent.

EP-A-030 408. European Binding Application discloses binders. However, no information is given on the specific surface area of the cementitious component in the binders, only the particle size is given.

EP-A-476 941. The specific surface area of the binders disclosed in European Patent Application Publication No. EP-A-2 is lower than the specific surface area given in this patent.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a binder which, when used, does not require any conventional solidification accelerators at all and can be completely omitted. Thus, the reflection is significantly reduced when the binder is used in the preparation of shotcrete or mortar. Due to the high adherence of the concrete or mortar prepared using the binder of the present invention, the product can be applied without technical modifications to both types of conventional sputtering processes; nevertheless, sufficient strength can be achieved within 1 to 5 hours for tunnel construction.

According to the present invention, the above object is solved by the Blaine specific surface area of the fine cement and / or fine clinker being> 12,000 cm ² / g, preferably 15,000-20,000 cm ² / g.

In particular, the binder of the present invention is suitable for the production of aerated concrete or mortar, which can be processed in a dry and wet process, without affecting the environment. We found that the find3

The task of our invention can be surprisingly and very advantageously solved by the use of a commercially available cement [e.g. widely used in the Austrian tunnel construction "FAT 20" budworm-portland and PZ 287 (H) 5 blast furnace slag Portland cement "tunnel cement"] 5-80% by weight, specially manufactured with a very high grinding fineness [specific surface area according to Blaine, preferably> 12 000C ² / g] cement or clinker. In the dry process we prefer to use high quality cement, while in the wet process we prefer high quality cement (e.g. the product marketed as "Microcem A and B" by Cement Works of Heidelberg or as "Microdur P" by Dyckemoff or any cement product can be easily produced by breeding).

Thus, according to the present invention, a mixture of two different grinding cements (wet process) and a very high grinding mortar is used for 20 [Blaine specific surface area> 12,000 cm ² / g] (dry process).

The term "fine cement" as used in the present specification and claims is intended to mean ground clinker without the use of plaster. 25

Preferred compositions of the binder of the present invention are claimed in the dependent claims.

Preferably, the cementitious mortar or mortar of the present invention can be processed by the wet process as follows. In the process, concrete or mortar containing water and, optionally, additives and a binder containing fines are sprayed onto the surface to be coated; the process is characterized in that the fine clinker is mixed only immediately before the concrete or mortar exits the firing device, and is particularly preferably added to the nozzle. The above procedure prevents premature hardening of concrete or mortar.

The specifications of the fine cement corresponding to the above indications are as follows:

Microcem A:

Blaine specific surface area approx. Particle size

Microcem B:

Blaine specific surface area approx. Particle size

000 cm ² / g 95% <16 gm.

000cm ² / g 100% <10 gm 98% <8 gm.

Below is a Duriment GK4 Formulation [Wietersdorfer-Peggauer Cement Works Prefabricated Dry Ready Concrete; A 5% alkaline material-based commercial accelerator (Addiment BE2) was compared to samples containing no O-type accelerator but containing microcement instead of PZ 275 (H) 20. In addition, we work with and without a fluxing agent (Liquiment from Chemie Linz) and various microcements (Wietersdorfer microcement, Heidelberger microcement "Microcem B" (commercial product), and Wietersdorfer microcement with reduced SO ₃ content). Spraying operations are carried out on site using the Aliva 242 dry type equipment, with an AW / B value (water cement ratio) of about 0.55 for non-fluxing mixtures and about 0.50 for flux containing mixtures.

The composition of Duriment Throat Reinforced Concrete (Sprayed Concrete) GK4 Formula (the formulation is otherwise referred to as "mortar mix"):

Largest particle size

Bulk weight (volumetric weight)

Beginning of consolidation

Completion of consolidation

The Addiment BE-2 accelerator is a sodium aluminate-based alkaline hardening accelerator (manufactured by Heidelberg Baustofftechnik).

Liquiment is a naphthalene sulfonate resin based fluxing agent.

The results obtained are summarized in Table 1 below.

mm approx. 1600 kg / m ³ approx. 30 sec approx. 60 sec

Table 1

Sheaf- price bubble accelerator Mikroce- went Elfolyó- flux Compressive strength (N / mm ² ) Penetrometer needle 3 mm Compressive strength measured in drill core 6 minutes 15 minute 30 minute 1 hour 2 o'clock 3 hours 6 hours dL D3 D7 D28 0 5% BE-2 - - 0.4 0.6 0.7 0.9 1.0 > 1.2 n. t. 12.5 16.5 22.0 31.0 1 - 20% w + p - <0.1 <0.1 0.12 0.2 0.3 0.4 0.7 11.0 31.5 38.0 53.5 2 - 30% w + p - <0.1 0.2 0.3 0.4 0.5 0.7 > 1.2 21.0 27.0 32.8 49.0 3 - 30% w + p 0.53% <0.1 0.2 0.3 0.45 0.55 0.75 > 1.2 23.0 29.0 35.0 53.0 4 - 30% w + p (-SO ₃ ) 0.53% 0.1 0.3 0.45 0.6 0.75 0.95 > 1.2 33.0 39.0 44.5 59.0 5 - 50% w + p 0.53% 0.1 0.2 0.3 0.45 0.6 > 1.2 n. t. 38.2 43.0 62.0 61.0

HU 212 386 Β

Sheaf- price bubble accelerator Mikroce- went Elfolyó- flux Compressive strength (N / mm ² ) Penetrometer needle 3 mm Compressive strength measured in drill core 6 minutes 15 minute 30 minute 1 hour 2 o'clock 3 hours 6 hours dL D3 D7 D28 6 - 75% w + p 0.53% 0.15 0.3 0.4 0.5 0.8 > 1.2 n. t. 41.0 44.0 53.0 58.0 7 - 100% w + p 0.53% 0.15 0.25 0.4 0.6 0.9 > 1.2 n. t. 37.0 40.0 46.0 54.0 8 - 30% Microcem B - <0.1 0.2 0.3 0.45 0.6 1.1 > 1.2 29.0 38.5 40.5 49.0

n. t = not found “Liquiment Fluidizer w + p = microcement with technical specification as follows: Blaine specific surface area approx. 18,000 cm ² / g, particle size: 100% <10 µm, 95% <10 µm. BE-2 Sodium Aluminate Accelerator (trade name: "Addiment BE-2") w + p (-SOj) is a microcement according to the above specification, but the SOj content for the standard microcement is "w + p" compared to 3%.

Dust formation and reflection is the smallest at 10-30% and then up to 75% microcement, only powder is produced, with 100% microcement as powder and reflection as in the 0 mixture.

For all variants, a layer thickness of> 30 cm can be applied without difficulty in one session. Mixtures 3 and 4 are also sprayed through the head. Minimum Requirements for Aerated Concrete (Concrete Guidelines, January 1989

Dl > 5 N / mm ² ) performs smoothly for each formulation variant. The strength achieved in 1 hour is lower than that of the accelerated ready-mixed concrete using the methods used today. This is offset by higher adhesion. The shotcrete produced according to the invention solidifies very rapidly after 1 hour and the strength values obtained after 24 hours are far superior to those of the shotcrete produced by known methods.

The Addiment ST 2 stabilizer used in the mortar formulation for spreading experiments is chemically a cellulose ether.

The following mortar recipe is used for the experiments:

PZ275 (H) 20 170 kg fine cement substitute

Splitt 0 / 0.3 90 kg

0.3 / 0.8 310 kg 45

0.8 / 2.0 171 kg

2.0 / 4.0 250 kg

Addiment St 2 0.25 kg.

The concrete technical advantages of the binder according to the invention are as follows: 50

- less "bleeding";

- higher fastness;

- greater resistance to weather conditions;

- higher impermeability to water; 55

- better corrosion protection of fittings;

- reduced mechanical wear;

- faster hardening;

- higher reactivity on concrete additives. 60

A preferred embodiment of the present invention is described below:

Blain according to > 12,000 cm ² / g, particularly preferably 15,000-20,000 cm ² / g, ground or graded, with normal phase composition or blast, as well as HS-clinker are used for commercial cements in excess of 5%. for the production of. The cement thus produced enables the production of environmentally friendly shot-through concrete without the use of accelerators containing alkaline materials, with minimal reflection, both dry and wet.

As a further advantageous feature of the cement-microcement mixtures of the present invention, it has been found that the binders of the present invention react surprisingly strongly with commercially available concrete additives (e.g. accelerators). In particular, in the manufacture of fast-setting products, any commercially available accelerator (e.g., alkali metal hydroxides, alkali metal aluminates, alkali metal carbonates and / or water soluble alkali metal silicates) may be used to accelerate the bond. In contrast to the amount required for normal cements (often 5-7%), due to the high reactivity of the microcement in the mixture, the amount of accelerator can be reduced by at least 75%. According to laboratory tests, only 6% of the accelerator (sodium aluminate) can be achieved in accordance with the standards for aerated concrete. However, if 30% of the binder is replaced by microcement according to the invention, the desired instant strength can be achieved by adding 0.8% accelerator (sodium aluminate).

In summary, the present invention is, e.g. as follows:

The hydraulic binder of the present invention is a commercially available cement (e.g., pemye-portland cement, blast-furnace slag cement) and optionally an additive material for making concrete or mortar5.

EN 212 386 Β g, fine cement and / or fine clinker. The binder comprises at least 5% by weight of fine cement and / or fine clinker for concrete or mortar to be processed by wet process, and at least 5% for fine clinker for concrete and mortar to be processed by dry process. The specific surface area of fine cement and fine clinker is> 12,000 cm ² / g, preferably 15,000-20,000 cm ² / g. The binder may be combined with concrete additives. Due to the high reactivity of the microcement component in the binder, the amount of concrete additives can be reduced by at least 75% compared to conventional cements. When used in conjunction with commercially available concrete additives, the binder of the present invention can be used in an amount of 10-20% of the amount used in known binders to achieve the desired change in properties.

Claims (7)

Hydraulic binder for concrete or mortar, in particular dry or wet shot or mortar, for use in the manufacture of commercially available cement, e.g. pemye Portland cement, blast furnace slag cement and optionally additives, fine cement and / or fine clinker, characterized in that the fine surface of the fine cement and / or fine clinker is> 12,000 cm ² / g, preferably 15,000-20,000 ctn ² / g. Binder according to claim 1, characterized in that it contains at least 5% by weight of fine cement and / or fine clinker. The binder according to claim 2, characterized in that it contains 5 to 80% by weight, preferably 10 to 50% by weight, particularly preferably 20 to 30% by weight, of fine cement and / or fine clinker. 4. A binder according to any one of claims 1 to 3, characterized in that the concrete applied by the wet process contains fine cement. 5. A binder according to any one of claims 1 to 3, characterized in that the concrete applied by the dry process contains a fine clinker. 6. A binder according to any one of claims 1 to 3, characterized in that it is mixed with commercially available concrete additives. 7. A process for applying aerated concrete or mortar by a wet process comprising water and, where appropriate, additives, and the method of any of claims 1-4. A concrete or mortar containing a binder comprising a binder according to any one of claims 1 to 6 and 6 is injected onto the surface to be coated, characterized in that the fine clinker is mixed just before the concrete or mortar exits the spray equipment, preferably directly on the spray head.