Concrete constructions employing the use of a ductile strip

• US 6,694,690 B2
• Filed: 07/10/2001
• Issued: 02/24/2004
• Est. Priority Date: 07/10/2000
• Status: Active Grant

• Current Assignee: Board of Regents of the University of Michigan (University of Michigan)
• Original Assignee: Board of Regents of the University of Michigan (University of Michigan)
• Inventors: Zhang, Jun, Li, Victor C.
• Primary Examiner(s): Ramirez, Ramon O.
• Assistant Examiner(s): STERLING, AMY JO
• Application Number:
  US09/902,054
• Publication Number:
  US 20020046524A1
• Time in Patent Office: 959 Days
• Field of Search: 523/960.2, 523/960.4, 523/960.5, 525/891, 404/42
• US Class Current: 52/396.04
• CPC Class Codes: E01C 11/04 for cement concrete paving E01C9/001 takes precedence
• CPC Class Codes: E01C 7/147 Repairing concrete pavings, e.g. joining cracked road sections by dowels, applying a new concrete covering applying thin surface layers with other binder E01C7/35; repairing pavings in general E01C11/005; roughening by means of tools E01C11/24
• CPC Class Codes: E04B 1/68 of joints, e.g. expansion joints packing for joints in roads or airfields E01C11/02; expansion joints for bridges E01D19/06; sealing joints between foundation piles E02D5/14; joints in foundation structures E02D29/16; devices for sealing the spaces or joints between roof-covering elements E04D1/36; sealing joints between roof-covering elements E04D3/38; construction of joints for flooring or floor layers composed of a number of similar elements E04F15/02005; construction of joints for flooring or floor layers made of masses in situ E04F15/14
• CPC Class Codes: E04F 15/14 Construction of joints, e.g. dividing strips E04F15/02005 takes precedence; sealing joints not restricted to flooring E04B1/68 , construction of joints in roads or airfields E01C11/02
• CPC Class Codes: E04G 23/0203 Arrangements for filling cracks or cavities in building constructions
• CPC Class Codes: E04G 23/0214 using covering strips
• CPC Class Codes: Y02A 30/30 in transportation, e.g. on roads, waterways or railways

Abstract

The present invention relates to a concrete construction that comprises a concrete slab and a ductile strip adjacent the slab. The ductile strip comprises an engineered cementitious composite of cementitious material and reinforcing fibers with the ductile strip being directly bonded to the slab. The present invention also relates to a method of making or repairing a concrete construction, the method comprises providing a ductile strip adjacent a concrete slab, wherein the ductile strip is made of an engineered cementitious composite comprising cementitious material and hydrophilic and/or hydrophobic reinforcing fibers. The present invention further relates to a roadbed or building floors suitable for vehicular traffic, the roadbed comprises a plurality of slabs and ductile strips comprising an engineered cementitious composite of cementitious material and reinforcing fibers.

Claims

1. A concrete construction comprising:

a concrete slab; and

a ductile strip adjacent a first side of the slab, the ductile strip comprising an engineered cementitious composite of cementitious material and reinforcing fibers, the ductile strip being directly bonded to the slab.

2. The construction of claim 1 wherein hydrophilic fibers comprising polyvinyl alcohol fibers are present in the ductile strip.

3. The construction of claim 1 wherein a further concrete slab is present wherein the first concrete slab is adjacent a first side of the ductile strip and the second concrete slab is adjacent a second side of the ductile strip.

4. The construction of claim 1 wherein the ductile strip has a first crack strength lower than the tensile strength of the concrete slab.

5. The construction of claim 4 wherein the tensile strain capacity of the ductile strip is about 1-10%.

6. The construction of claim 1 wherein at least one dowel bar is provided that extends between and connects the slab and the ductile strip.

7. The construction of claim 1 wherein the ductile strip has a base section having at least one notch.

8. The construction of claim 1 wherein the ductile strip has an upper surface generally planar with an upper surface of the slab, the strip further having an interface surface in contacting relation with an interface surface of the slab, the interface surface of the strip being at about 5-90°

angle relative to the upper surface of the slab.

9. The construction of claim 1 wherein the concrete slab is made of a material having a tensile strain capacity of about 0.01-0.2% and the strip is made of a material having a tensile strain capacity of about 1-10%.

16. The construction of claim 1 wherein hydrophobic fibers comprising polyethylene are present in the ductile strip.

17. A roadbed suitable for vehicular traffic, said roadbed comprising a plurality of said slabs and said ductile strips of claim 1.

18. The roadbed of claim 17, where each ductile strip separates each slab of each adjacent pair of slabs.

19. A floor suitable for a parking structure, said floor comprising a plurality of said slabs and said ductile strips of claim 1, where each ductile strip separates each slab of each adjacent pair of slabs.

20. A floor suitable for a flat crack free factory or warehouse floor, said floor comprising a plurality of said slabs and said ductile strips of claim 1, where each ductile strip separates each slab of each adjacent pair of slabs.

21. The construction of claim 1, wherein the concrete slab is provided with grooved or stepped surfaces adjacent the ductile strip.

23. The construction of claim 1, wherein a second ductile strip is provided adjacent a second side of the slab, opposite the first side of the slab, each ductile strip having a width about 0.01-0.1 times the distance between the ductile strips.

25. A concrete bridge deck, said bridge deck comprising a plurality of said slabs and said ductile strips of claim 1, where each ductile strip separates each slab of each adjacent pair of slabs.

27. The construction of claim 3 wherein each slab has essentially the same shape.

28. The construction of claim 27 wherein each slab has an essentially uninterrupted quadrilateral upper surface.

29. The construction of claim 3 wherein the first and second sides of the strip extend essentially the length of the slabs.

30. The construction of claim 3 wherein a second ductile strip is present adjacent a second side of the second slab and a third concrete slab is present adjacent the second ductile strip, each ductile strip having a width about 0.01-0.1 times the distance between the ductile strips.

33. The construction of claim 5 wherein the ductile strip exhibits strain-hardening under uniaxial tension.

34. The construction of claim 33 wherein the reinforcing fibers have a fiber modulus (E) of about 20-250 GPa.

35. The construction of claim 34 wherein the fibers have a fiber tensile strength of about 500-4500 MPa.

36. The construction of claim 35 wherein the fibers have a diameter of about 0.015-0.10 mm and a length of about 3-30 mm.

37. The construction of claim 36 wherein the volume percent of the fibers in the cementitious composition ranges from 0.5 to 10 volume percent.

38. The construction of claim 36 wherein the fibers comprise hydrophobic fibers.

39. The construction of claim 38 wherein the fibers further comprise hydrophilic fibers.

40. The construction of claim 39 wherein the reinforcing fibers are randomly intermixed throughout the engineered cementitious composite.

41. The construction of claim 1 wherein the ductile strip has the same thickness as the concrete slab.

42. The construction of claim 1 wherein the cementitious material further comprises sand and fly ash.

10. A method of making or repairing a concrete construction, said method comprising:

providing a ductile strip adjacent a concrete slab, wherein the ductile strip is made of an engineered cementitious composite comprising cementitious material and hydrophilic and/or hydrophobic reinforcing fibers.

11. The method of claim 10 wherein the ductile strip is provided between adjacent two slabs of concrete.

12. The method of claim 10 wherein the ductile strip is cast prior to being provided adjacent the slab of concrete.

13. The method of claim 10 wherein the ductile strip is cast adjacent the slab of concrete.

14. The method of claim 10 wherein the ductile strip has a first crack strength lower than the tensile strength of the concrete slab.

15. The method of claim 10 wherein hydrophilic fibers comprising polyvinyl alcohol are present in the ductile strip.

22. The method of claim 10, wherein the concrete slab is provided with grooved or stepped surfaces adjacent the ductile strip.

24. The method of claim 10, wherein a second ductile strip is provided adjacent a second side of the slab, opposite the first side of the slab, each ductile strip having a width about 0.01-0.1 times the distance between the ductile strips.

26. A method of repairing concrete structure comprising a plurality of concrete slabs and expansion strips separating the concrete slabs, said method comprising:

providing a ductile strip between the adjacent concrete slabs of the pair of concrete slabs where an expansion strip was, wherein the ductile strip is made of an engineered cementitious composite comprising cementitious material and hydrophilic and/or hydrophobic reinforcing fibers.

31. A concrete construction comprising:

a plurality of essentially uniformly shaped concrete slabs; and

a plurality of spaced apart and essentially parallel ductile strips made of an engineered cementitious composite comprising cementitious material and hydrophilic reinforcing fibers, each set of the slabs being separated by one of the strips such that each ductile strip has a width about 0.01-0.1 times the distance between adjacent ductile strips.

32. The construction of claim 31 wherein no ductile strips are present that extend in an essentially perpendicular manner with respect to any of the ductile strips.