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
  • C04B28/00—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements
  • C04B28/02—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements containing hydraulic cements other than calcium sulfates
• • 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
  • C04B24/00—Use of organic materials as active ingredients for mortars, concrete or artificial stone, e.g. plasticisers
  • C04B24/24—Macromolecular compounds
  • C04B24/26—Macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds
  • C04B24/2641—Polyacrylates; Polymethacrylates
• • 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
  • C04B2111/00172—Sprayable, i.e. concrete-like, materials able to be shaped by spraying instead of by casting, e.g. gunite by the wet process

Definitions

• Plastic-modified shotcrete or spraying mortar process for its production and its processing
• the present invention relates to sprayed concrete or sprayed mortar modified with a special copolymer, a process for its production and its processing.
• Shotcrete and shot mortar have been used for many decades in the areas of sewer rehabilitation, sewage collectors, tunnels, construction icons, mining consolidation and engineering structures, for example
• Shotcrete and shot mortar are applied in one or more layers during installation, preferably in thicknesses from a few mm up to 6 to 8 cm.
• the applied layers are crack-free after hardening, have a high bond to the subsurface as well as low shrinkage during hardening. This requires special post-treatment measures in accordance with DIN 18551 and DIN 1045 and the guidelines of the German Committee for Reinforced Concrete.
• the known shotcrete shows an extremely high rebound even when properly applied, especially when aggregates are added, both in the dry spraying process and in the wet spraying process.
• the coarsest components of a shotcrete or shot mortar mixture accumulate. This then leads to an inhomogeneous composition of the sprayed concrete or mortar.
• the strength class with regard to bending tension and compressive strength of the shotcrete or shot mortar can be adjusted via the cement classes, in accordance with DIN 1045 or DIN 18551 (W. Manns et al. Concrete 37, 317-319 (1987)).
• the purely inorganic compositions can be modified in accordance with the prior art in order to improve special properties.
• microsilica for shotcrete leads to a high strength, brittle
• Shotcrete Processing can be carried out in dry and wet spray processes.
• the layer thickness can be reduced due to the very high compressive strength.
• An extremely low water / cement ratio (W / Z value) is used.
• plastics to modify the shotcrete are also known. These are reactive resins, in particular epoxy resins, which are incorporated into the preparation mixture for the shotcrete together with a hardener component and water (DE-A 23 01 617, DE-A 31 36 737). When using two-component reactive systems, there is a risk of clogging of the nozzles and spraying device, since the premixed system can only be processed for a certain period of time (pot life).
• the plastic additives are supplied, for example, in the form of anhydrous one- or multi-component additives (DE-C 36 41 947).
• DE-C 36 41 947 The advantages of these resin-hardened shotcrete are both the improved mechanical characteristics and the lower Water penetration depth. However, the rebound is not yet satisfactory in the case of the known modified shotcrete and shotcrete.
• polymers to the shotcrete mixtures in order to increase or extend the flowability, for example polyalkylene oxide-modified styrene / maleic anhydride copolymers (DE-A 195 39 250) or to accelerate the setting behavior (DE-A 39 25 306) , for example by adding polycarboxylate copolymers.
• polymers for example polyalkylene oxide-modified styrene / maleic anhydride copolymers (DE-A 195 39 250) or to accelerate the setting behavior (DE-A 39 25 306) , for example by adding polycarboxylate copolymers.
• An object of the present invention was therefore to provide a plastic-modified shotcrete or shotcrete that can be processed without changing the process technology at the lowest possible W / Z value and has a processing time comparable to that of the corresponding unmodified shotcrete or shotcrete, whose
• Bending tensile strength and compressive strength as well as static and dynamic modulus of elasticity at least correspond to the unmodified shotcrete, the corrosion resistance and penetration tightness of which is significantly improved in relation to aqueous and organic media and the rebound during application is as low as possible.
• This object was achieved by means of a shotcrete or spraying mortar containing cement, sand and optionally gravel, and water and a styrene / (meth) acrylate copolymer dispersion, the styrene / (meth) acrylate copolymer content being in the range from 1 to 40% by weight .-%, based on the cement content.
• the present invention also relates to a process for the preparation of a shotcrete or shotcrete, which is characterized in that cement, sand and optionally gravel are mixed with water and a styrene / (meth) acrylate copolymer dispersion.
• the present invention further relates to a method for processing a shotcrete or shot mortar, which is characterized in that a liquefied mixture of cement, sand and optionally gravel and water and a styrene / (meth) acrylate copolymer dispersion is conveyed by means of a pump and is applied to the surface to be treated via a nozzle.
• the styrene / (meth) acrylate copolymer is mixed into the mixing water in the form of an aqueous plastic dispersion and, in the case of the dry spray process, is metered in at the nozzle via the normal water supply; in the case of the wet spray process, the pre-assembled mixing water is analogous to that
• the preparation mixture homogenized and liquefied in a compulsory mixer is conveyed to the spray nozzle by means of a pump, preferably with a screw pump in the case of spray mortar, and preferably with a piston pump in the case of shotcrete, in particular in a dense phase process.
• the preparation mixture is preferably driven out of the nozzle by means of compressed air of, for example, 2.5-4 bar and applied to the application area.
• the shotcrete or shot mortar according to the invention preferably contain 1 to 40% by weight, particularly preferably 3 to 25% by weight, in particular 5 to 20% by weight, based on the cement, styrene / (meth) acp lat copolymer.
• copolymers are used that have an approval according to DIN 1045. In compliance with the requirements specified in the approval according to DIN 1045
• Concentration range must be the shotcrete or shot mortar produced with it according to DIN 18551 cannot be checked separately.
• copolymers contained according to the invention in shotcrete or shot mortar are preferably in the form of aqueous dispersions with an average glass transition temperature> 0 ° C. and a minimum film-forming temperature (MFT) of
• a particularly suitable example of spray mortars or shotcrete according to the invention are aqueous plastic dispersions based on anionic copolymers of the following monomers:
• plastic dispersions are, for example, those based on anionic copolymers as follows
• Composition 52 to 55 parts by weight of styrene,
• these dispersions preferably contain customary ionic and in particular anionic and / or customary nonionic tensioactive compounds in the amounts customary in emulsion polymerizations.
• the plastic dispersions contain, as emulsifiers, based on the anionic copolymer, 0.3 to 2% by weight, preferably 0.5 to 1.5% by weight, particularly preferably 0.6 to 1% by weight, anionic Emulsifiers, preferably sulfo-containing emulsifiers, particularly preferably alkali metal salts of sulfuric acid half-esters of oxyethylated alkylphenols, and 1 to 5% by weight, preferably 1.5 to 3% by weight, particularly preferably 2 to 2.5% by weight, nonionogenic emulsifiers, preferably alkylphenol polyglycol ether, particularly preferably nonylphenol polyglycol ether or tributylphenol polyglycol ether with preferably 15 to 50 ethylene oxide
• the shotcrete according to the invention contains cement as an inorganic building material, preferably in an amount of 200 to 500 kg / m 3 , particularly preferably 300 to 450 kg / m 3 , in particular 350 to 400 kg / m 3 .
• the proportion of binder can be changed by adding other binders, for example fly ash, in an amount of up to 50% by weight, based on cement, in addition to cement.
• the shotcrete contains sands with a grain size of up to 2 mm in amounts of preferably 400 to 1000 kg / m 3 , particularly preferably 500 to 950 kg / m 3 , in particular 700 to 900 kg / m 3 , sands with a grain size of 2 to 4 mm in Quantities of preferably 100 to 800 kg / m 3 , particularly preferably 200 to 700 kg / m 3 and in particular 300 to 500 kg / m 3 , as well as any gravel
• Composition and grain shape of the grain size 4 to 8 mm in amounts of preferably 200 to 500 kg / m 3 , particularly preferably 250 to 400 kg / m 3 , in particular 250 to 350 kg / m 3
• Spray mortars differ from shotcrete by the lack of gravel with a grain size greater than 4 mm.
• the spray mortar according to the invention contain Cement preferably in an amount of 200 to 650 kg / m 3 , particularly preferably 300 to 550 kg / m 3 , in particular 350 to 500 kg / m 3 .
• the spray mortar contains sands with a grain size of up to 2 mm in quantities of preferably 800 to 2000 kg / m 3 , particularly preferably 1000 to 1400 kg / m 3 , in particular 1100 to 1300 kg / m 3 , and sands with a grain size of 2 to 4 mm in amounts of preferably up to 500 kg / m 3 , particularly preferably 100 to 400 kg / m 3 , in particular 120 to 300 kg / m 3 .
• the mixtures of cement, sand and optionally gravel are made ready for application by adding water, a water / cement ratio (W / Z value) in the range from 0.35 to 0.45, in particular 0.37 to 0, 41, in the dry spray process and 0.4 to 0.6, in particular 0.45 to 0.55, in the wet spray process are preferred.
• the water-cement factor is calculated as the proportion of water based on the total proportion of cement.
• the air void content in the hardened shotcrete or shot mortar is preferably in the range from 1 to 10% by volume, in particular 1.5 to 4% by volume, based on the concrete or mortar (test according to DIN 1045 and 1048 or the ISO replacing it - Standards ISO 1920, 2736/1, 2736/2, 4012, 4013, 4103, 4848, 7031, 4109).
• low-foam plastic dispersions are preferably used and defoamers are added if necessary.
• the sprayed concrete and sprayed mortar applied according to the invention show a 30 to 50% lower rebound compared to the non-modified sprayed concrete and sprayed mortar.
• the sprayed mortar and sprayed concrete applied according to the invention can be reprofiled significantly better on the surface, that is, smoothed, abraded and structured.
• the sprayed mortars or shotcrete prepared using the preparation mixtures and dispersions tested according to DIN 1045 do not require any further approval according to DIN 18551.
• the sprayed mortars or shotcrete applied according to the invention are distinguished by increased penetration tightness and corrosion resistance.
• the penetration tightness was determined according to guideline part 4 of the German Committee for Reinforced Concrete (DafStb) "Concrete construction when handling water-polluting substances”.
• Drill cores made of sprayed mortar and shotcrete were examined to improve their resistance to acidic attack by sulfuric acid pH 1.
• Spray mortar SM 4 P with 0.20% by weight Mowilith LDM 6880 (styrene / acrylate dispersion, Hoechst AG), based on the cement content of the dry mortar mixture
• Shotcrete SM 8 P with 0.10% by weight Mowilith LDM 6880, based on the cement content of the dry mortar mixture
• Spray mortar SM 4 P with 10% by weight Mowilith LDM 6880, based on the
• test specimens were left in the acid bath for 70 days.
• the pH value was kept constant with an autotitrator over the entire test period.
• Dry spraying process Production and application: In the dry spraying process, factory-made dry mixes with tested quality ( ® Sakret spray mortar SM4P and ® Sakret shotcrete SB8P, Sakretshubautechnik GmbH) are applied with a conventional dry spraying machine according to the rotor principle ( ® Aliva 246). To do this, the mixing water is first mixed with the plastic dispersion, taking into account the water content introduced via the dispersion. The water-
• Dispersion mixture is added via the normal spray nozzles (volcanic nozzles) into the wetting part using a booster pump under at least 8 bar.
• Water / dispersion mixture seamlessly modified and applied unmodified become. It is not necessary to clean the machines between the changing compositions.
• a solidification accelerator (as a dry component in the preparation mixture) can also be used in thicker application thicknesses of, for example, 10 cm.
• test specimens were produced in one layer in accordance with DIN 18551 and tested.
• Cement CEMI 42.5R (DIN 1164) 8.0 kg cement, in a 40 kg container ready mix (Sakret SM4P) with the largest grain 4 mm, water: 3.2 kg W / Z value: 0.40
• Modified spray mortar The rebound is reduced by 30 - 50% compared to unmodified spray mortar.
• Composition The rebound is reduced by 30 - 50% compared to unmodified spray mortar.
• Cement CEMI 42.5R (DIN 1164) 8.0 kg in a 40 kg container ready mix (Sakret SM4P) with largest grain 4 mm, type of dispersion: Mowilith LDM 6880 quantity of dispersion: 0.8 kg
• Amount of dispersion, based on cement 10% by weight
• Amount of dispersion 1.2 kg of dispersion, based on cement: 15% by weight
• Amount of dispersion 1.60 kg of dispersion, based on cement: 20% by weight
• Corrosion resistance s. 1.1.1 for measurement, depth of damage: 4 mm
• Corrosion resistance s. 1.1.1 for measurement, depth of damage: 4.5 mm
• Amount of dispersion, based on cement 15% by weight
• Dispersion type Mowilith LDM 6880 Amount of dispersion: 1.44 kg
• Amount of dispersion, based on cement 20% by weight
• factory-made dry mixes with tested quality (Sakret spray mortar SM 4P and Sakret shotcrete SB 8P) are used, which are produced on site in suitable mixers, preferably compulsory mixers.
• the supply mixture can also be manufactured and delivered in a pre-determined and tested recipe in a ready-mixed concrete plant.
• the plastic dispersions to be added according to the invention are used in the ready-mixed concrete plant or in the mixer at the construction site in the desired concentration, in the area of approval according to DIN 1045, up to the respective maximum concentration or in the case of an individual approval according to DIN 18551 in the approved concentration range.
• the wet modified supply mixture can be applied with the mortar and concrete pumps on the market and the conventional spray nozzles, as in the dry spraying process. Spray mortar in the wet spray process is preferably conveyed with screw pumps, the promotion in dense flow and in
• the shotcrete according to the invention which in Wet spraying processes are preferably carried out with a piston pump, whereby sealing and thin-flow processes can be used.
• the shotcrete and shot mortar according to the invention allow a simple device cleaning by water after the application has ended. Installation type: single-layer (up to max. 6 cm application thickness).
• Cement CEMI 42.5R (DIN 1164) 8.0 kg in a 40 kg container ready mix (Sakret SM4P) with the largest grain 4 mm;
• Amount of dispersion 0.80 kg
• Amount of dispersion, based on cement 10% by weight
• Cement CEMI 42.5R (DIN 1164): 8.0 kg in a 40 kg container ready mix (Sakret SM4P) with the largest grain 4 mm, type of dispersion: Mowilith LDM 6880 quantity of dispersion: 1, 20 kg
• Cement CEMI 42.5R (DIN 1164) 8.0 kg in a 40 kg container ready mix (Sakret SM4P) with largest grain 4 mm,
• Amount of dispersion, based on cement 20% by weight

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

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• 1997
  • 1997-06-04 DE DE19723474A patent/DE19723474A1/de not_active Ceased
• 1998
  • 1998-06-02 WO PCT/EP1998/003264 patent/WO1998055420A1/de not_active Application Discontinuation
  • 1998-06-02 JP JP50147499A patent/JP2002502348A/ja not_active Ceased
  • 1998-06-02 EP EP98933583A patent/EP0996600A1/de not_active Withdrawn

Patent Citations (4)

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