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EP-4118054-B1 - MINERAL BINDER

EP4118054B1EP 4118054 B1EP4118054 B1EP 4118054B1EP-4118054-B1

Inventors

  • VALCKE, Siska Lisa Albertine
  • VISSER, Johanna, Hendrica, Maria
  • GARZÓN AMÓRTEGUI, Juan Felipe

Dates

Publication Date
20260506
Application Date
20210315

Claims (14)

  1. A mineral binder suitable for use in binding aggregate in a mineral mortar or concrete mixture, said binder comprising the following components: a) at least 40 wt.% of a calcined kaolinitic clay and ultrafine crushed construction and demolition waste (CDW), wherein the ultrafine CDW has a maximum diameter of 250 µm, b) 2-50 wt.% of a chemical activator; and wherein the calcined kaolinitic clay, the ultrafine crushed CDW and the chemical activator are present in a combined amount of at least 90 wt.%, based on the total weight of the mineral binder.
  2. The mineral binder according to the previous claim, wherein the calcined kaolinitic clay, the ultrafine crushed CDW and the chemical activator are present in a combined amount of at least 95 wt.%, preferably at least 99 wt%. based on the total weight of the mineral binder.
  3. The mineral binder according to any of the preceding claims, wherein the ultrafine crushed CDW is selected from the group consisting of ultrafine crushed ceramics, ultrafine crushed concrete and combinations thereof, preferably selected from the group consisting of ultrafine crushed brick, ultrafine crushed masonry and combinations thereof, most preferably wherein the ultrafine crushed CDW is ultrafine crushed brick.
  4. The mineral binder according to any of the preceding claims, wherein the ultrafine crushed CDW is ultrafine crushed brick and wherein the calcined kaolinitic clay and ultrafine crushed brick contains between 70-80 wt.% of SiO 2 , between 10 and 20 wt.% of Al 2 O 3 and between 2 and 6 wt.% of Fe 2 O 3 , based on the total weight of the ultrafine crushed CDW and the calcined kaolinitic clay.
  5. The mineral binder according to any of the preceding claims, wherein the calcined kaolinitic clay is metakaolin.
  6. The mineral binder according to any of the previous claims, wherein the weight ratio between calcined kaolinitic clay and ultrafine CDW is 1:1 to 1:9, preferably between 1:1 and 2:8, more preferably between 1:1 and 3:7.
  7. The mineral binder according to any of the preceding claims, wherein the CDW has a maximum diameter of 200 µm, preferably 150 µm.
  8. The mineral binder according to any of the previous claims containing less than 1 wt.%, preferably less than 0.5 wt.%, more preferably less than 0.1 wt.% of fly ash, slag, metal tailings, rice husk ash, volcanic ash and silica fume.
  9. A mineral mortar precursor mixture, suitable for use in a mineral mortar mixture, based on the mineral binder according to any of the previous claims in an amount of 15-50 wt.%, said mineral mortar precursor mixture further comprising: c) 50-85 wt.% of a fine aggregate comprising particles having a diameter of up to 4 mm, preferably between 155 µm and 4 mm; and wherein the combined amount of components a)-c) is at least 90 wt.%, preferably at least 95 wt.%, more preferably at least 99 wt.% based on the total weight of the mineral mortar precursor mixture.
  10. A mineral mortar mixture based on the mineral mortar precursor mixture of claim 9 in an amount of 65-96 wt.%, wherein said mineral mortar mixture comprises said chemical activator and wherein said mineral mortar mixture further comprises: d) water in an amount of 25 wt.% or less, preferably 4-25 wt.% of water; wherein the combined amount of components a)-d) is at least 90 wt.%, preferably at least 95 wt.%, more preferably at least 99 wt.% based on the total weight of the mineral mortar mixture.
  11. A concrete precursor mixture, suitable for use in a concrete mixture, based on the mineral binder according to any of claims 1-8 in an amount of 15-45 wt.%, said precursor concrete mixture further comprising: c) 50-85 wt.% of a coarse and optionally fine aggregate, wherein the coarse aggregate comprises particles having a diameter of between 4 mm and 50 mm; and wherein the combined amount of components a)-c) is at least 90 wt.%, preferably at least 95 wt.%, more preferably at least 99 wt.% based on the total weight of the concrete precursor mixture.
  12. A concrete mixture based on the concrete precursor mixture of claim 11 in an amount of 65-96 wt.%, wherein said concrete mixture comprises said chemical activator and wherein said concrete mixture further comprises: d) 4-25 wt.% of water; wherein the combined amount of components a)-d) is at least 90 wt.%, preferably at least 95 wt.%, more preferably at least 99 wt.% based on the total weight of the concrete mixture.
  13. A method for the preparation of a cured mineral mortar mixture or cured concrete, said method comprising providing the mortar mixture according to claim 10 or the concrete mixture according to claim 12, and allowing said mixture to cure.
  14. The method according to claim 13, wherein curing is achieved by allowing the mineral mortar mixture to stand for at least 12 h, preferably at least 18 h, more preferably at least 24 h, and preferably wherein curing is achieved at a temperature between 20 °C and 60 °C, more preferably 25 °C to 50 °C, even more preferably between 30 °C to 40 °C.

Description

The invention relates to a mineral binder, a mineral mortar precursor mixture, a mineral mortar or concrete mixture, and and a method for the preparation of a cured mineral mortar or concrete mixture. Mineral binders are inorganic substances that are capable of binding aggregate to form a strong mineral mortar or concrete that is suitably used for construction purposes. Ordinary Portland cement is the most commonly used mineral binder and consists of calcium silicates (clinker) which are prepared by sintering limestone and aluminum-silicates. The process of preparing Ordinary Portland cement (OPC) is energy-consuming as high temperatures typically in the range of 1500 °C are required to prepare the clinker material. Next to the energy consumption and related CO2 emissions, the calcination of limestone (CaCO3) during the process releases high amounts of CO2. Mineral binders without Ordinary Portland cement, such as for example geopolymers, form a more environmentally friendly alternative to Ordinary Portland cement. They constitute a class of inorganic materials containing reactive minerals such as aluminosilicates which can undergo dissolution and polycondensation reactions. Under alkaline conditions, the reactive minerals dissolve into Si-O and Al-O phases which engage into a polycondensation reaction to form a network of linked Al-silicate phases. Such mineral binders can be employed to bind various components such as aggregates and are therefore advantageously used in mineral mortar and concrete mixtures. Such mineral mortar mixtures, when cured, advantageously exhibit excellent mechanical properties, high durability and thermal stability. Furthermore, the mineral mortar or concrete mixture can be prepared at ambient or slightly higher temperature and can further advantageously be prepared from waste materials. This combination of properties makes such mineral mortar and concrete mixtures a sustainable alternative to common construction materials such as Ordinary Portland Cement based mortars and concrete. Typical reactive minerals which can be used as base materials for such mineral mortar mixtures or concrete mixtures include fly ash, calcined clays, silica fume or ground granulated slag. Thus, by selecting a suitable combination of precursor reactive minerals, the properties of the obtained mineral mortar mixture or concrete mixture can be modulated. In CN106495585, a geopolymer composition is disclosed that is prepared from metakaolin, fly ash and slag as reactive minerals and further comprises fine and coarse aggregate to form a geopolymer-based concrete suitable for use as pavement material. The disadvantage of CN106495585, however, is that the formed geopolymer exhibits an invariable greyish color, which is not suitable for applications wherein the color grey is not desired, e.g. for aesthetic reasons. CN 108 101 577 A discloses a mineral binder in an inorganic foam insulation material. To acquire the desired color, a pigment can be added, but this requires the presence of an additional component in the geopolymer mixture, which adds costs and complexity to the preparation method. Furthermore, it is typically cumbersome to mimic the colors of natural rocks or stones with pigments, and thus often an artificial look is obtained. Also, the pigment is expensive and typically does not contribute to the strength of the product that can be obtained by the mixture, which makes it an expensive component compared to the overall cheap mineral components of the strength inducing binder components. It is an object of the invention to provide a mineral binder suitable for use in a mineral mortar or concrete mixture, which mineral mortar mixture or concrete mixture has desired and/or selectable (i.e. good) aesthetic features, provides high strength and shows good water and acid resistance when cured. Such mineral mortar and concrete mixtures are suitable for applications wherein both good performance, i.e. high strength and/or good durability, as well as good aesthetics are required. Figure 1 shows the preparation of a particular building unit as described in the invention. Top: a mold is filled with a layer of mineral mortar mixture and an insulating rigid core is placed on top of the mineral mortar mixture. Bottom: the rigid core is covered with mineral mortar mixture and the mineral mortar mixture can be allowed to cure. The inventors found that a mineral binder can be obtained which is suitable for use in binding aggregate in a mineral mortar or concrete mixture, and provides the mineral mortar mixture and concrete mixture with advantageous properties, such as high strength, good durability (including freeze-thaw), good aesthetics and strong adherence to a rigid substrate. Typically, binding fine aggregate results in the mineral mortar, while binding fine and coarse aggregate results in the concrete mixture. Accordingly, the invention relates to a mineral binder as defined in claim 1. The calcined kaolinitic