Classifications

• • C—CHEMISTRY; METALLURGY
  • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
  • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
  • C04B7/00—Hydraulic cements
  • C04B7/36—Manufacture of hydraulic cements in general
  • C04B7/48—Clinker treatment
  • C04B7/52—Grinding ; After-treatment of ground cement
  • C04B7/527—Grinding ; After-treatment of ground cement obtaining cements characterised by fineness, e.g. by multi-modal particle size distribution
• • C—CHEMISTRY; METALLURGY
  • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
  • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
  • C04B2111/00—Mortars, concrete or artificial stone or mixtures to prepare them, characterised by specific function, property or use
  • C04B2111/00034—Physico-chemical characteristics of the mixtures
  • C04B2111/00146—Sprayable or pumpable mixtures
  • C04B2111/00155—Sprayable, i.e. concrete-like, materials able to be shaped by spraying instead of by casting, e.g. gunite

Definitions

• the invention relates to a hydraulic binder for concrete or mortar, in particular for concrete or mortar to be processed in the dry or wet spray process, preferably tunnel concrete, with a content of commercially available cement, such as fly ash cement, slag cement and optionally aggregates and with a content on fine cement and / or fine clinker.
• a hydraulic binder for concrete or mortar in particular for concrete or mortar to be processed in the dry or wet spray process, preferably tunnel concrete, with a content of commercially available cement, such as fly ash cement, slag cement and optionally aggregates and with a content on fine cement and / or fine clinker.
• the binder according to the invention is particularly suitable for shotcrete or mortar for producing environmentally friendly shotcrete in any (conventional) spraying technique (dry and wet spraying methods).
• the binder according to the invention can be used wherever rapid solidification and high early strength are important.
• the use in shotcrete and mortar in the production of cement-bound wood fiber boards and in the production of concrete pipes can be mentioned as examples.
• Shotcrete is installed in the so-called “new Austrian tunnel construction" using the wet or dry spray method and is one of the most important supporting measures. If sufficient compressive strengths and layer thicknesses are achieved, the shotcrete layer can be statically tightened for the final tunnel expansion.
• the dry spraying process the dried aggregate is mixed with the cement or delivered to the construction site as a finished mixture and water is only added at the nozzle.
• the desired rapid setting can be achieved by adding a (liquid) setting accelerator to the nozzle, but also by mixing a powdered setting in the cement / aggregate mixture.
• the cement In the wet spraying process, the cement is premixed with moist aggregates and water, delivered to the construction site and conveyed to the spray nozzle with a special pump.
• a solidification accelerator (EB agent) is attached to the nozzle. mixed in so that the concrete solidifies quickly.
• Solidification accelerators customary today consist essentially of alkali hydroxides, alkali aluminates, alkali carbonates and / or water-soluble alkali silicates. These solidification accelerators are strongly alkaline and lead to serious health damage when handled carelessly (especially chemical burns on the people working as the nozzle operator / foreman). In addition, these solidification accelerators must not get into the groundwater or the receiving water. In addition, the solidification accelerators have a very negative influence on the further development of the strength of the concrete, since the rapid solidification produces a very porous concrete.
• Shotcrete is the outermost layer of a tunnel against the basement and therefore very often comes into contact with water. Depending on the amount and chemical nature of the water, components can be removed from the shotcrete. This is strongly promoted by the above-mentioned porous concrete structure caused by the solidification accelerators. Above all, the alkalis added for acceleration are responsible for a high pH of the water running off. This contaminated water must never get into the ground water (drinking water) and can lead to damage in the drainage (precipitation, further leaching). Attempts have already been described to solve the problems mentioned.
• AT-B-382 859 proposes a calcium sulfate-free cement (ie clinker ground without gypsum) for the production of shotcrete with a specific Blaine surface area of 2,000-8,000 cm 2 / g.
• AT-B-382 859 is therefore limited to dry shotcrete.
• spoonbinders show an extremely poor strength development.
• the spray cement produced according to AT-B-382 859 is very little resistant to sulfate attack.
• JP-A-50-98 514 Portland cement is mixed with quick cement and early high strength cement in order to achieve certain properties.
• a product that contains sodium gluconate and sodium carbonate is named as quick cement. These products are harmful to the environment.
• JP-A-50-98 514 uses a normal PZ 475 (Blaine 5300 cm 2 / g) as Portland cement, but not a micro-cement.
• JP-A-60-180 944 a normal cement is mixed with up to 40% extra-fine cement (Blaine> 6,000 cm 2 / g, preferably Blaine 9,000 cm 2 / g) and mixed with ⁇ 30% water in order to achieve early to produce high-strength molded concrete parts.
• extra-fine cement Blaine> 6,000 cm 2 / g, preferably Blaine 9,000 cm 2 / g
• the high early strengths of cement / fine cement mixtures are used in particular. Not used and in JP-A-60-180 944 too
• JP-A-58-223 652 proposes a mixture of normal Portland cement with microsilica and a "calcic expanding material". This latter material has very high contents of CaO (free lime) and CaF 2 as well as a clinker phase typical of some quick cements (HCa0. Al 2 0 3 .CaF 2 ). Micro cement is not mentioned. No particularly fine hydraulic phase is used either.
• the mortar obtained according to JP-A-58-223 652 is said to be usable as a joint filler in concrete components.
• DE-A-3 503 385 relates to a binder mixture of Portland cement, alumina cement, limestone and hydrated lime and discloses the addition of concrete flow agents and solidification accelerators. This is exactly one of those mixtures which should be avoided for environmental reasons, since the solidification accelerator used (water glass or a related substance) is harmful to the environment.
• the addition of alumina cement to accelerate solidification brings with it the known disadvantages of such mixtures (reduced resistance, low final strengths).
• DE-A-2 055 120 mentions the addition of cement as a powdery accelerator at the spray nozzle as an unsatisfactory possibility of accelerating solidification.
• DE-A-2055 120 teaches the admixing of a residual portion of milled clinker to the nozzle.
• DE-B-2 341 493 describes the mixture of a normal Portland cement with a special calcium aluminate cement.
• the acceleration of setting is based on the special properties of C 12 A 7 , but not on the high fineness of one of the components.
• DE-B-1211097 in turn describes a mixture of Portland cement and alumina cement as well as anhydrite.
• the special their properties are based on the admixture of alumina cement, but not on a high fineness and thus reactivity of part of the binder mixture.
• the rapid solidification is to be achieved directly at the nozzle by admixing a suspension or concrete mixture to alumina cement and / or calcium haloaluminum cement.
• the object of the present invention is to provide a binder, the use of which does not require conventional solidification accelerators.
• the rebound should be significantly reduced if the binder is used for shotcrete or mortar. Due to the high stickiness of the concrete or mortar mixed with the binder according to the invention, it should be possible to apply the product without technical modifications in both conventional spraying methods, to give the young concrete more time than before to solidify and thus to improve the strength development and fewer pores to be achieved and nevertheless to ensure sufficient early strengths for a further tee in tunnel construction after 1 to 5 hours.
• the fine cement and / or fine clinker has a specific surface area of Blaine> 12,000 cm 2 / g, preferably from 15,000 to 20,000 cm 2 / g.
• the present invention provides a binder, in particular for shotcrete or mortar, which can be processed both in the dry and in the wet spraying process without environmentally harmful influences. It was found that this was achieved surprisingly and particularly well if a commercially available cement - for example the fly ash cement "FAZ 20" or slag cement PZ 275 (H) 20 (“tunnel cement”) with 5 to 80, which is widely used in Austrian tunnel construction %
• a specially produced cement or clinker of very high fineness (Blaine> 8,000 cm 2 / g), preferably Blaine> 12,000 cm 2 / g) is added.
• the method is preferably the ultra-fine clinker, for the wet spraying method the ultra-fine cement (which is available, for example, under the name “Microcem” A “and” B “from the Heidelberg cement works or” Microdur P “from Dyckerhoff, or in each Cement works can be easily produced by sifting.)
• a mixture of two cements of different grinding fineness wet spraying method
• a mixture of a conventional cement with clinker of very high grinding fineness Blaine> 8000 cm 2 / g
• Teroc - Kenspritzclar very high grinding fineness
• fine cement is understood to mean a clinker ground with gypsum additive and "fine clinker” to mean a clinker ground without gypsum additive.
• compositions of the binder according to the invention are the subject of the dependent claims.
• a method according to the invention in which the concrete or mortar containing water and optionally additives and binder containing fine clinker is sprayed onto the surface to be coated, which is thereby characterized is characterized in that the fine clinker is mixed only immediately before the concrete or mortar emerges from the spraying device, in particular directly at the spray nozzle. This prevents the concrete or mortar from solidifying prematurely.
• Fine cements with the designations mentioned above have the following specifications: Microcem A: Blaine: about 11,000 cm 2 / g
• the spraying was carried out using an Aliva 242 spraying machine suitable for the construction site using the dry spraying method.
• the W / B value (water / binder value) was about 0.55 for the mixtures without a plasticizer; for mixtures with a condenser about 0.50.
• Duriment Gork4 concrete GCR4 formulation is composed as follows (otherwise the formulation corresponds to the "mortar mixture” mentioned below):
• Rubble weight about 1,600 kg / m 3
• Solidification end about 60 sec
• the accelerator Addiment BE-2 is an alkaline solidification accelerator (manufacturer: Heidelberger Baustofftechnik) based on sodium aluminate.
• Liquiment is a condenser based on naphthalene sulfonate resin.
• BE-2 is an accelerator based on sodium aluminate (trade name "Addiment BE-2)
• w & p (-S0 3 ) is a micro cement of the above specification, the S0 3 content compared to normal micro cement" w & p "being 3% is reduced.
• the Addiment ST 2 stabilizer used in the mortar formulation for the spray tests is chemically a cellulose ether.
• a preferred feature of the invention is as follows: The use of specific surfaces of Blaine> 8000 cm 2 / g. preferably Blaine> 12,000 cm 2 / g, in particular Blaine 15,000 to 20,000 cm 2 / g ground or sifted cements or clinker of the usual phase composition and HS clinker as an admixture in proportions from 5% to commercially available cements for the production of spray cement.
• This spraying cement subsequently enables the production of environmentally friendly sprayed concrete without accelerators containing alkali and with minimized rebound in the dry as well as in the wet spraying process.
• any commercially available accelerator e.g. alkali hydroxides, alkali aluminates, alkali carbonates and / or water-soluble alkali silicates
• the dosage required for normal cements can be reduced by at least 75% due to the high reactivity of the micro-cement used in the mixture.
• a sprayed concrete of strength class J3 of the sprayed concrete guideline with a normal sprayed concrete could only be achieved with a dosage of 6% accelerator (sodium alumina), and 30% of the binder could be replaced by micro-cement Early strength can be achieved by adding only 0.8% of the same accelerator.
• the invention can be represented as follows, for example:
• a hydraulic binding agent for concrete or mortar with a content of commercially available cement, such as fly ash cement, slag cement and possibly aggregates, and with a content of fine cement and / or fine clinker.
• the binder contains at least 5% by weight of fine cement for the production of concrete or mortar, in particular tunnel concrete, to be processed in the wet spray process and for the production of Dry spraying process for processed concrete or mortar, especially tunnel concrete, at least 5% by weight of fine clinker.
• the fine cement and the fine clinker have a specific surface area of> 12,000 cm 2 / g, preferably from 15,000 to 20,000 cm 2 / g.
• the binder can be combined with concrete admixtures.
• the dosage of these concrete additives can be reduced by at least 75% compared to conventional cements. If commercially available concrete admixtures are added to the binder according to the invention, dosages on the order of 10 to 20% of the dosages customary in known binders are sufficient to achieve the desired changes in properties.

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• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Ceramic Engineering (AREA)
• Materials Engineering (AREA)
• Structural Engineering (AREA)
• Organic Chemistry (AREA)
• Lining And Supports For Tunnels (AREA)
• Curing Cements, Concrete, And Artificial Stone (AREA)

Applications Claiming Priority (3)

Publications (1)

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• 1992
  • 1992-05-13 AT AT98092A patent/AT397244B/de not_active IP Right Cessation
• 1993
  • 1993-05-10 WO PCT/AT1993/000078 patent/WO1993023342A1/de active IP Right Grant
  • 1993-05-10 CZ CZ942777A patent/CZ285665B6/cs not_active IP Right Cessation
  • 1993-05-10 EP EP93911654A patent/EP0640061A1/de not_active Withdrawn
  • 1993-05-10 SK SK1353-94A patent/SK281228B6/sk unknown
  • 1993-05-10 HU HU9403171A patent/HU212386B/hu not_active IP Right Cessation

Non-Patent Citations (1)

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