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
  • 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
  • C04B28/04—Portland cements
• • 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
  • C04B40/00—Processes, in general, for influencing or modifying the properties of mortars, concrete or artificial stone compositions, e.g. their setting or hardening ability
  • C04B40/06—Inhibiting the setting, e.g. mortars of the deferred action type containing water in breakable containers ; Inhibiting the action of active ingredients
  • C04B40/0608—Dry ready-made mixtures, e.g. mortars at which only water or a water solution has to be added before use
• • 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
• • 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
• • 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
  • C04B2111/00474—Uses not provided for elsewhere in C04B2111/00
  • C04B2111/00482—Coating or impregnation materials
  • C04B2111/00517—Coating or impregnation materials for masonry

Definitions

• Plasters and renders are mineral layers deposited on building substrates, especially walls, in particular exterior walls (for renders) and interior walls or ceilings (for plasters). Renders provide waterproofing and make the outside façade more visually appealing, while plasters contribute to the aesthetics of the room, either directly, when they are not covered by paint or wallpapers, or otherwise indirectly by providing a smooth and flat surface.
• Pneumatic spraying equipment traditionally comprise a compressor, a pump and spray gun connected by hoses to the compressor and the pump. It is important when using this technique that the mortar composition shows a good pumpability. This term can be defined as the ability to flow through pipes and hoses by the help of a pump while maintaining the fresh and hardened properties of the mortar. To this end, it has been observed in the past that a small amount of hydrated lime acted as a lubricant and therefore greatly improved the pumpability of the mortar.
• the production of hydrated lime (Ca(OH) 2 ) however involves calcination of calcium carbonate (limestone) at high temperatures, followed by addition of water. This process creates a huge amount of CO 2 emissions, both because of the chemical reaction of calcination itself, that releases CO 2 , and because of the fuel combustion process used to heat the kiln for the calcination process.
• the invention aims at providing a dry mortar composition showing a good pumpability together with a low CO 2 footprint.
• an object of the invention is a dry mortar composition
• a dry mortar composition comprising a hydraulic binder and aggregates, said aggregates comprising particles of ground concrete in an amount of 0.5 to 5.0wt% with respect to the weight of dry mortar.
• the particles of ground concrete are particles of ground autoclaved aerated concrete.
• Autoclaved aerated concrete is a lightweight, precast, foam concrete building material suitable for producing concrete masonry unit like blocks.
• AAC products are manufactured by curing under heat and pressure in an autoclave a mixture of quartz sand, calcined gypsum, lime, cement, water and aluminum powder. During its manufacturing, some wastes are produced, for example blocks that do not comply with the specifications. These blocks can be ground in order to obtain a powder that can be used in the composition according to the invention.
• the aggregates additionally comprise aggregates selected from siliceous, calcareous aggregates, dolomitic aggregates and mixtures thereof. Examples are ground limestone or dolomite and silica sand. A mixture of silica sand and limestone is preferred.
• the aggregates preferably comprise sands (size 0-5 mm) and fillers (size 0-0.1 mm).
• the total amount of aggregates in the dry mortar composition is preferably 50 to 95wt%, even 65 to 90wt%.
• the hydraulic binder is preferably selected from Ordinary Portland Cements, Calcium Aluminate Cements, Calcium Sulfoaluminate Cements, fly ashes, ground granulated blast furnace slags, hydraulic lime, source of calcium sulfate and mixtures thereof.
• the hydraulic binder is Ordinary Portland Cement (OPC), especially of the CEM I type, as defined in EN 197-1 Standard.
• OPC Ordinary Portland Cement
• the amount of hydraulic binder in the dry mortar composition is preferably 5-30wt%, especially 8-25wt%.
• the dry mortar composition may further comprise additives selected from redispersible polymer powders, plasticizers, superplasticizers, accelerators, retarders, rheological modifiers, water-retention agents, pigments, defoaming agents and mixtures thereof.
• the total amount of additives in the dry mortar composition is preferably 0.001 to 2.0wt%, especially 0.005 to 0.5wt%.
• the dry mortar composition advantageously does not comprise hydrated lime, since it can be completely substituted by the ground concrete.
• the method for depositing a plaster or a render on a building substrate comprises mixing the dry mortar composition with water to obtain a wet mortar, pumping said wet mortar, and projecting said wet mortar on said building substrate.
• the building substrate is preferably a wall, for example an exterior wall for a render, or an interior wall for a plaster.
• the wall may be constructed by any known method, for example by pouring concrete between formworks, by joining masonry elements such as bricks or concrete blocks, or by 3D-printing of mortar.
• the building substrate may also be an insulation panel in the case of external thermal insulation systems (ETICS).
• ETICS external thermal insulation systems
• Projecting the wet mortar on the building substrate is preferably done by pneumatic spraying.
• the weight ratio of water to the dry mortar composition is preferably 0.10 to 0.20.
• the thickness of the render or plaster is preferably 1 to 20 mm (especially after 28 days of hardening).
• hydrated lime was replaced by ground AAC with a D50 of 12 ⁇ m and a D90 of 35 ⁇ m.
• Table 1 hereafter shows the properties of the wet mortar after mixing with water, with a water/dry mortar weight ratio of 0.15.
• the compressive and flexural strengths were measured according to EN1015-11 Standard. The consistency was evaluated by using a flow table and measuring the diameter (in cm) of the wet mortar when it spreads on a table.
• Table 2 shows the characteristics of the hardened mortar.

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

Applications Claiming Priority (2)

Publications (2)

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• 2023
  • 2023-01-27 EP EP23752516.7A patent/EP4476193A4/de active Pending
  • 2023-01-27 WO PCT/IB2023/050706 patent/WO2023152589A1/en not_active Ceased

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