MINERAL BINDER

Abstract

The invention relates to 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 calcined kaolinitic clay and ultrafine crushed CDW,
wherein the ratio between calcined clay and ultrafine crushed CDW is between 3:7 and 1:1 (w/w),
b) optionally 2-50 wt. % of a chemical activator; and
wherein the calcined kaolinitic clay, the ultrafine crushed CDW and the optionally present chemical activator are present in a combined amount of at least 90 wt. %, based on the total weight of the binder. The invention further relates to mineral mortar or concrete mixtures based on this mineral binder, as well as building units made from these mixtures.

Claims

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), 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 binder.

2. The mineral binder according to claim 1, wherein the calcined kaolinitic clay, the ultrafine crushed CDW and the chemical activator are present in a combined amount of at least 95 wt. %, based on the total weight of the mineral binder.

3. The mineral binder according to claim 1, wherein the ultrafine crushed CDW is selected from the group consisting of ultrafine crushed ceramics, ultrafine crushed concrete and combinations thereof.

4. The mineral binder according to claim 1, 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.sub.2, between 10 and 20 wt. % of Al.sub.2O.sub.3 and between 2 and 6 wt. % of Fe.sub.2O.sub.3, based on the total weight of the mineral binder.

5. A mineral mortar precursor mixture suitable for use in a mineral mortar mixture based on the mineral binder according to claim 1 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; and wherein the combined amount of components a)-c) is at least 90 wt. %, based on the total weight of the mineral mortar precursor mixture.

6. A mineral mortar mixture based on the mineral mortar precursor mixture of claim 5 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, wherein the combined amount of components a)-d) is at least 90 wt. %, based on the total weight of the mineral mortar mixture.

7. A concrete precursor mixture suitable for use in a concrete mixture based on the mineral binder according to claim 1 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. %, based on the total weight of the concrete precursor mixture.

8. A concrete mixture based on the concrete precursor mixture of claim 7 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. %, based on the total weight of the concrete mixture.

9. A building unit based on the cured mineral mortar mixture of claim 6, comprising a soluble calcium content of less than 12.5 wt. %.

10. A building unit comprising a rigid layer, the rigid layer is at least partly covered with an outer layer of the cured mineral mortar mixture according to claim 6, wherein the outer layer has a layer thickness in the range of 0.5 to 30 mm.

11. The building unit according to claim 10, wherein at least 10% of the surface of the rigid layer is covered by the outer layer.

12. The building unit according to claim 10 wherein the outer layer has a maximum layer thickness of less than 20% based on the total thickness of the building unit.

13. The building unit according to claim 10, wherein said rigid layer comprises an insulating material having a thermal conduction value (A) less than 0.065 W/mK.

14. The building unit according to claim 10, wherein said rigid layer comprises an insulating material selected from the group consisting of expanded polystyrene (EPS), extruded polystyrene (XPS), polyisocyanurate (PIR), polyurethane (PUR), polyisocyanurate (PIR), biobased insulation materials, stonewool, glasswool, foamglass, hemp wool, phenolic foam, aerogel and combinations thereof.

15. A method for the preparation of the building unit according to claim 10, comprising the steps of: providing the rigid layer in a suitable form; covering at least 10% of the surface of the rigid layer with the mineral mortar mixture; and allowing said mineral mortar mixture to cure.

16. (canceled)

17. A building, comprising the building units according to claim 10.

18. A sewage system, comprising the building units according to claim 9.

19. (canceled)

20. (canceled)

21. The mineral binder of claim 1, wherein the calcined kaolinitic clay is metakaolin.

22. The building unit of claim 10, wherein said rigid layer is a rigid insulating layer with insulating properties.

23. A building unit based on the cured concrete mixture of claim 8, comprising a soluble calcium content of less than 12.5 wt. %.

Description

EXAMPLE 1 PREPARATION OF THE BUILDING UNIT

[0077] A mineral mortar mixture was prepared by adding successively 60 g water, 340.6 g of soluble silicate (47-52 wt. % solid; molar ratio Na.sub.2O or K.sub.2O to SiO.sub.2:0.6-1.2), 1350 g sand, 213.9 g ultrafine crushed red brick (diameter<125 μm) and 213.9 g metakaolin powder to a Hobart mixer and mixing the mixture for five minutes. The mineral composition of the metakaolin and ultrafine crushed red brick is described in Table 1.

TABLE-US-00001 TABLE 1 mineral composition of the ultrafine crushed brick and metakaolin Ultrafine crushed Mineral (wt. %) red brick metakaolin SiO.sub.2 76.6 69.9 Al.sub.2O.sub.3 10.4 22.3 CaO 2.14 0.75 MgO 1.01 0.17 Fe.sub.2O.sub.3 4.51 3.14 Na.sub.2O 0.88 <0.10 K.sub.2O 2.22 0.26 Mn.sub.3O.sub.4 0.14 <0.02 TiO.sub.2 0.67 1.10 SnO.sub.2 <0.02 <0.02 MoO.sub.3 <0.01 <0.01 SrO 0.01 <0.01 PbO <0.01 <0.01 ZnO 0.02 <0.01 CuO <0.01 <0.01 NiO <0.02 <0.02 CoO <0.01 <0.01 Cr.sub.2O.sub.3 0.01 <0.01 V.sub.2O.sub.5 <0.02 <0.02 BaO 0.05 <0.03 ZrO.sub.2 0.05 0.07 P.sub.2O.sub.5 0.15 <0.10 LOI — — Total <98.96 <98.07
A layer of about 4 mm or 8 mm of the mixture was poured into a mold with dimensions of 20×10×5 cm. A block of XPS (19.2×9.2×4.2 or 19.6×9.6×4.6 cm) was placed on top of the layer and fixed with pins to the mold to prevent floating (see FIG. 1 top view). More of the mixture was added until the XPS was completely covered with the mineral mortar mixture (FIG. 1 bottom view). Excess of the mixture was removed and the building unit was covered and left to cure for one day at 40° C. The mold was removed and the building units were subjected to further testing.

EXAMPLE 2 FREEZE-THAW RESISTANCE

[0078] The building units of Example 1 were subjected to an accelerated freeze thaw test according to the standard test method NEN EN 772-22. For this, two walls were built of 0.25 m.sup.2 following the scheme of the standard and submerged in water for 7 days. Subsequently, the walls were subjected to 100 cycles of: (120±5) min at (−15±3) ° C., then (20±1) min at (20±3) ° C. and (120±10) seconds of splash water. After the 100 cycles, the walls were left at room temperature to thaw completely. After freeze-thaw testing according to NEN-EN 772-22:2019, the insulation bricks did not show any visual damage. The mortar does not have any influence on the performance of the insulation bricks in the freeze-thaw cycles.

EXAMPLE 3—PAVEMENT TILES

[0079] Three earth-dry mortar prisms ([1], [2] and [3]) were prepared in the lab for testing for the application of pavement tiles with a binder and a mineral mortar mixture thereof having compositions as provided in Table 2. The compressive strength and binding strength were also determined as described herein-above.

TABLE-US-00002 TABLE 2 composition and strength of earth-dry mortar prisms [1] [2] [3] w/w % w/w % w/w % Fine sand 67 68 67 Metakaolin powder 19 20 19 Activator (47-52 wt. % solid; molar ratio 14 7 9 Na.sub.2O or K.sub.2O to SiO.sub.2:0.6-1.2) Ca(OH).sub.2 activator — — 0.6 Water 0 6 4 Total mortar mixture 100 100 100 Total solid activator content 7 3.5 5 Total water content 7 9.5 8 Compressive strength (MPa) 69 20 52 Bending strength (Mpa) 7 3 6