Monolithic building element with photocatalytic material

Abstract

A building element may be formed from a first cementitious mixture and a second cementitious mixture containing a photocatalytic cementitious mixture. The first cementitious mixture and the photocatalytic cementitious mixture may be co-formed into a shaped uncured two layer monolith having a base layer of the first cementitious mixture and a top layer of the photocatalytic cementitious mixture. The shaped uncured two layer monolith is then cured. The resulting building element may be algae-resistant.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

In the several figures of the attached drawing, like parts bear like reference numerals, and:

FIG. 1 is a diagrammatic side view of an apparatus useful in producing a shaped uncured monolithic building element in accordance with an embodiment of the invention; and

FIG. 2 is a diagrammatic side view of a building element produced by the apparatus of FIG. 1.

Claims

1. A method of forming a building element, comprising steps of: providing a first cementitious material;mixing a photocatalytic material into a second cementitious mixture to create a photocatalytic cementitious mixture;co-forming a shaped uncured two layer monolith comprising a base layer of the first cementitious material and a top layer of the photocatalytic cementitious mixture; andcuring the uncured two layer monolith.

2. The method of claim 1, wherein curing the uncured two layer monolith comprises curing the base layer and the top layer simultaneously.

3. The method of claim 1, wherein curing the uncured two layer monolith provides a monolithic building element having a cured base layer, a cured photocatalytic layer and an interface therebetween.

4. The method of claim 3, wherein the interface has a cohesive strength that is at least about as high as a cohesive strength of the cured base layer and/or the cured photocatalytic layer.

5. The method of claim 1, wherein the second cementitious mixture has a composition at least substantially identical to that of the first cementitious mixture.

6. The method of claim 5, wherein the first cementitious mixture is uniformly dispersed throughout the uncured base layer and the uncured photocatalytic layer.

7. The method of claim 6, wherein the uncured base layer has substantially no photocatalytic material and the uncured photocatalytic layer includes about 10 to about 30 volume percent photocatalytic material.

8. The method of claim 1, wherein the building element comprises a roof tile or a siding element.

9. The method of claim 1, wherein the uncured base layer has a thickness of about 2 to about 3 centimeters and the uncured photocatalytic layer has a thickness of about 2 to 3 millimeters.

10. The method of claim 1, further comprising, prior to curing, a step of providing a polymer overcoat onto the uncured photocatalytic layer.

12. The method of claim 1, wherein mixing a photocatalytic material into the second cementitious mixture comprises mixing into the second cementitious mixture a material selected from the group consisting of TiO2, ZnO, WO3, SnO2, CaTiO3, Fe2O3, MoO3, Nb2O5, TixZr(1-x)O2, SiC, SrTiO3, CdS, GaP, InP, GaAs, BaTiO3, KNbO3, Ta2O5, Bi2O3, NiO, Cu2O, SiO2, MoS2, InPb, RuO2, CeO2, Ti(OH)4, and combinations thereof.

13. The method of claim 1, wherein mixing a photocatalytic material into the second cementitious mixture comprises mixing into the second cementitious mixture a material selected from the group consisting of a doped photocatalytic material, a nanocrystalline photocatalytic material, and combinations thereof.

14. The method of claim 1, further comprising a step, prior to curing, of applying a polymeric topcoat to the uncured two layer monolith.

15. The method of claim 1, further comprising a kiln drying step.

16. An algae-resistant building element, comprising: a base layer comprising a first cured cementitious mixture;an algae-resistant layer disposed on the base layer, the algae-resistant layer comprising a photocatalytic material dispersed within a second cured cementitious mixture; andan interface formed between the base layer and the algae-resistant layer;wherein the interface has a cohesive strength that is at least as high as a fracture strength of the base layer and/or the algae-resistant layer.

17. The algae-resistant building element of claim 16 wherein the first cementitious mixture comprises cement or clay.

18. The algae-resistant building element of claim 16, wherein the second cementitious mixture comprises cement or clay.

19. The algae-resistant building element of claim 16, further comprising an acrylate layer applied over the algae-resistant layer.

20. The algae-resistant building element of claim 16, wherein the photocatalytic material is selected from the group consisting of TiO2, ZnO, WO3, SnO2, CaTiO3, Fe2O3, MoO3, Nb2O5, TixZr(1-x)O2, SiC, SrTiO3, CdS, GaP, InP, GaAs, BaTiO3, KNbO3, Ta2O5, Bi2O3, NiO, Cu2O, SiO2, MoS2, InPb, RuO2, CeO2, Ti(OH)4, and combinations thereof.

21. The algae-resistant building element of claim 16, wherein the photocatalytic material is selected from the group consisting of a doped photocatalytic material, a nanocrystalline photocatalytic material, and combinations thereof.

22. The algae-resistant building element of claim 16, wherein the algae-resistant layer includes about 10 to about 30 volume percent photocatalytic material.

23. The algae-resistant building element of claim 22, wherein the photocatalytic material comprises anatase TiO2.

24. The algae-resistant building element of claim 16, comprising a roof tile or a siding element.

25. The algae-resistant building element of claim 16, wherein the base layer has a thickness of about 2 to about 3 centimeters and the algae-resistant layer has a thickness of about 2 millimeters to about 3 millimeters.