Process for the production of concrete building products

• US 5,108,679 A
• Filed: 11/02/1990
• Issued: 04/28/1992
• Est. Priority Date: 06/11/1988
• Status: Expired due to Term

• Current Assignee: Redland ROOF Tiles Limited
• Original Assignee: Redland ROOF Tiles Limited
• Inventors: Wingfield, Jeremy, Rirsch, Eric
• Primary Examiner(s): AFTERGUT, KAREN K
• Application Number:
  US07/607,114
• Time in Patent Office: 543 Days
• Field of Search: 264/148, 264/211.11, 264/177.11, 264/177.18, 264/177.2, 264/108, 264/333, 264/211, 264/157, 264/163, 264/118, 264/122, 264/DIG. 31, 264/DIG. 49 , 264/297.1, 106/711, 106/802, 106/805, 106/675, 106/676, 106/679, 106/698, 106/705, 106/716, 106/782, 106/801, 106/681, 106/718, 106/811
• US Class Current: 264/118
• CPC Class Codes: C04B 16/06 fibrous
• CPC Class Codes: C04B 18/146 Silica fume
• CPC Class Codes: C04B 2103/32 Superplasticisers
• CPC Class Codes: C04B 2111/00129 Extrudable mixtures
• CPC Class Codes: C04B 2111/00594 Concrete roof tiles
• CPC Class Codes: C04B 24/26 obtained by reactions only involving carbon-to-carbon unsaturated bonds C04B24/243 takes precedence
• CPC Class Codes: C04B 28/02 containing hydraulic cements other than calcium sulfates
• CPC Class Codes: C04B 40/024 Steam hardening, e.g. in an autoclave
• CPC Class Codes: E04D 1/04 of ceramics, glass or concrete, with or without reinforcement
• CPC Class Codes: E04D 1/16 of ceramics, glass or concrete, with or without reinforcement
• CPC Class Codes: Y02W 30/91 Use of waste materials as fillers for mortars or concrete
• CPC Class Codes: Y10S 264/31 Processes of making tile and tile-like surfaces
• CPC Class Codes: Y10S 264/49 Processes of using fly ash

Abstract

A process for the production of concrete roofing products of reduced weight loading having a thickness in section of not greater than 15 mm. The process involves forming an asbestos-free cementitious composition comprising (i) lightweight aggregate, (ii) hydraulic cement, (iii) water and (iv) reinforcing fibers in an amount of not more than 4% by weight of the total weight of the composition but the fibers being present in an amount sufficient to provide a reinforcing effect and impact strength in the roofing product, the cementitious composition being capable of being shaped by a roller and slipper method, and thereafter shaping the cementitious composition by the method to provide a shaped extrudate, dividing the extrudate to form sections and curing the sections to provide roofing products, wherein the reinforcing fibers have lengths of 0.5 mm to 20 mm. The impact resistant roofing products are useful as roofing tiles, or a replacement for shingles, shakes and slates.

Claims

1. A process for production of concrete roofing products of reduced weight loading having high flexural strength and high impact strength and a thickness in section of not greater than 15 mm which process comprises forming an asbestos-free cementitious composition comprising (i) lightweight aggregate, (ii) hydraulic cement, (iii) water and (iv) reinforcing fibres in an amount of not more than 4% by weight of a total weight of said composition and said fibres being present in an amount sufficient to provide a reinforcing effect, high flexural strength and high impact strength in said roofing products, said formed cementitious composition being capable of being shaped by a roller and slipper method, and thereafter shaping said formed cementitious composition by said roller and slipper method to produce a shaped extrudate, dividing said extrudate to form sections and curing said sections to produce said roofing products of reduced weight loading having high flexural strength and high impact strength, wherein said reinforcing fibres have lengths of 0.5 mm to 20 mm.

2. A process as claimed in claim 1 wherein said composition additionally comprises a plasticiser or a superplasticiser.

3. A process as claimed in claim 1 in which an aspect ratio of said fibres is from 10 to 5000.

4. A process as claimed in claim 1 wherein said composition further comprises from 1 to 30% silica fume calculated as a percentage on a weight of hydraulic cement in said composition.

5. A process as claimed in claim 1 wherein particle size of said lightweight aggregate is from 0.5 to 1.50 mm.

6. A process as claimed in claim 1 wherein a weight ratio of water:

hydraulic cement in said composition is from 0.15;

1 to 0.90;

1.

7. A process as claimed in claim 1 wherein a weight ratio of water:

hydraulic cement in said composition is from 0.5;

1 to 0.7;

1.

8. A process as claimed in claim 1 wherein said composition is cured using an autoclave.

9. A process as claimed in claim 1 further comprising shaping said composition to provide roof tiles.

10. A process as claimed in claim 1 further comprising shaping said composition to form roof slates.

11. A process as claimed in claim 1 wherein said percentage by weight of reinforcing fibres to said total weight of said composition is from 0.15% to 1%.

12. A process as claimed in claim 11 wherein said percentage by weight of reinforcing fibres to said total weight of said composition is preferably in a range 0.15 to 0.35%.

13. A process as claimed in claim 1 wherein said reinforcing fibres are polypropylene fibers.

14. A process as claimed in claim 10 in which as aspect ratio of said fibres is from 10 to 600.

15. A process as claimed in claim 1 wherein said lightweight aggregate is a mixture of lightweight and non-lightweight aggregates.

16. A process as claimed in claim 15 in which up to 30% of said lightweight aggregate by weight is non-lightweight aggregate.

17. A process as claimed in claim 1 wherein a weight ratio of lightweight aggregate:

hydraulic cement in said composition is from 1;

1 to 4;

1.

18. A process as claimed in claim 17 wherein said weight ratio of lightweight aggregate:

hydraulic cement in said composition is substantially 2;

1.

19. A process as claimed in claim 1 wherein said reinforcing fibres have lengths of from 4 mm to 8 mm.

20. A process as claimed in claim 19 in which an aspect ratio of said fibres is from 18 to 4000.

21. A process as claimed in claim 19 wherein said length of said reinforcing fibres is substantially 6 mm.

22. A process as claimed in claim 21 in which an aspect ratio of said fibres is from 20 to 3000.

23. A process for production of concrete roofing products of reduced weight loading having high flexural strength and high impact strength and a thickness in section of not greater than 15 mm which process comprises forming an asbestos-free cementitious composition comprising (i) lightweight aggregate, (ii) hydraulic cement, (iii) water, (iv) reinforcing fibres in an amount of not more than 4% by weight of a total weight of said composition and said fibres being present in an amount sufficient to provide a reinforcing effect, high flexural strength and high impact strength in said roofing products, and (v) a polymer latex in weight ratio of polymer, calculated as dry weight, to said hydraulic cement within a range of 5:

100 to 50;

100, said formed cementitious composition being capable of being shaped by a roller and slipper method, and thereafter shaping said formed cementitious composition by said roller and slipper method to produce a shaped extrudate, dividing said extrudate to form sections and curing said sections to product said roofing products of reduced weight loading having high flexural strength and high impact strength, wherein said reinforcing fibres have lengths of 0.5 mm to 20 mm.

24. A process as claimed in claim 23 wherein said weight ratio of polymer, calculated as dry weight, to hydraulic cement is from 2:

100 to 15;

100.

25. A process as claimed in claim 23 wherein said weight ratio of polymer, calculated as dry weight, to hydraulic cement is from 3:

100 to 5;

100.

26. A process for production of concrete roofing products of reduced weight loading having high flexural strength and high impact strength and a thickness in section of not greater than 15 mm which process comprises forming an asbestos-free cementitious composition comprising (i) lightweight aggregate, (ii) hydraulic cement, (iii) water and (iv) reinforcing fibres in weight percent to a total weight of said composition of 0.15% to 4%, said formed cementitious composition being capable of being shaped by a roller and slipper method, and thereafter shaping said formed cementitious composition by said roller and slipper method to produce a shaped extrudate, dividing said extrudate to form sections and curing said sections to produce said roofing products of reduced weight loading having high flexural strength and high impact strength, wherein said reinforcing fibres have lengths of 2.0 mm to 20 mm.

27. A process for production of concrete roofing products of reduced weight loading having high flexural strength and high impact strength and a thickness in section of not greater than 15 mm which process comprises forming an asbestos-free cementitious composition comprising (i) lightweight aggregate, (ii) hydraulic cement, (iii) water, (iv) reinforcing fibers in weight percent to a total weight of said composition of 0.15% to 4%, and (v) a polymer latex in weight ratio of polymer, calculated as dry weight, to said hydraulic cement within a range of 5:

100 to 50;

100, said formed cementitious composition being capable of being shaped by a roller and slipper method, and thereafter shaping said formed cementitious composition by said roller and slipper method to produce a shaped extrudate, dividing said extrudate to form sections and curing said sections to produce said roofing products of reduced weight loading having high flexural strength and high impact strength, wherein said reinforcing fibres have lengths of 2.0 mm to 20 mm.