2. PowerPoint ® Presentation Chapter 4 Flatwork Flatwork Applications Site Preparation Concrete Reinforcement Flatwork Procedures Joint Control Bleedwater Pervious Concrete F-Numbers Hardeners

3. Chapter 4 — Flatwork Common types of flatwork include concrete pavements, floors, and walkways.

4. Chapter 4 — Flatwork Concrete for one-way and two- way joist systems is placed as a single, continuous member with the girders and beams.

5. Chapter 4 — Flatwork Dome pans are used to form two-way joist floor systems. Compressed air is used to separate the dome forms from the hardened concrete.

6. Chapter 4 — Flatwork Floors are classified based on their final use.

7. Chapter 4 — Flatwork Commercial and residential driveways are built to standard widths.

8. Chapter 4 — Flatwork A driveway is sloped depending on site conditions, the size of the driveway, and final appearance desired.

9. Chapter 4 — Flatwork A drainage system is installed on driveways that slope toward a garage.

10. Chapter 4 — Flatwork Curbs and gutters are classified as barrier, which redirects a vehicle, and mountable, which allows a vehicle to cross over.

11. Chapter 4 — Flatwork Slipforming greatly reduces the labor required to form and place curbs and gutters.

12. Chapter 4 — Flatwork Site preparation requirements include excavating and compacting subgrade, setting forms, installing plumbing and electrical systems, and setting rebar.

13. Chapter 4 — Flatwork Print specifications detail form and reinforcement requirements.

14. Chapter 4 — Flatwork The welded wire fabric number provides information on wire spacing, size, and whether wire is smooth (W) or deformed (D).

15. Chapter 4 — Flatwork Chairs are made of steel, plastic, or precast concrete and support reinforcement material at the proper elevation.

16. Chapter 4 — Flatwork Rebar increases the tensile strength of concrete and can contain lugs to improve bonding with concrete.

17. Chapter 4 — Flatwork Rebar is held in place with wire ties used at intersecting points.

18. Chapter 4 — Flatwork Tie bars are used between concrete sections to connect multiple slab sections.

19. Chapter 4 — Flatwork Dowels ensure vertical and horizontal alignment on slabs exposed to heavy bending loads. Aggregate interlock prevents uneven vertical movement when light bending loads are applied.

20. Chapter 4 — Flatwork Proper dowel size and spacing must be used during concrete placement to ensure adequate concrete strength and to avoid cracking.

21. Chapter 4 — Flatwork Common formwork materials are dimensional lumber, aluminum alloy, and steel.

22. Chapter 4 — Flatwork Setting forms to the proper elevation is accomplished with a carpenter’s level, transit level, or string.

23. Chapter 4 — Flatwork Forms must be properly set to ensure a level concrete slab.

24. Chapter 4 — Flatwork Screed systems are made of metal or wood and level concrete to the proper elevation.

25. Chapter 4 — Flatwork Placement should start at the point farthest from the concrete supply and work in continuous strips back toward the concrete supply.

26. Chapter 4 — Flatwork Placement, consolidation, and finishing procedures are completed simultaneously on different sections of fresh concrete.

27. Chapter 4 — Flatwork When a load is applied, compressive and tensile forces generate internal stresses resulting in cracks in the concrete.

28. Chapter 4 — Flatwork Two commonly-used types of control joints are sawed and tooled.

29. Chapter 4 — Flatwork Tooled control joints are useful for small slabs, such as a sidewalk.

30. Chapter 4 — Flatwork An alternative to hand-tooled control joints is to embed preformed metal or plastic strips into concrete.

31. Chapter 4 — Flatwork Control joint spacing is determined by the depth of the slab.

32. Chapter 4 — Flatwork Expansion joints are used at the juncture of two concrete components to allow concrete the freedom to move.

33. Chapter 4 — Flatwork Column bases use both expansion joints and control joints to allow a column to move freely of the concrete slab and to avoid additional stresses on the slab.

34. Chapter 4 — Flatwork Construction joints are formed using bulkheads and keystocks. The bulkhead separates two placements of concrete and the keystock forms a groove (keyway) to maintain alignment and bond between two sections of concrete.

35. Chapter 4 — Flatwork Warping joints help eliminate cracking caused by the bending of concrete from temperature or moisture differences between the top surface and the bottom of the slab.

36. Chapter 4 — Flatwork Pervious concrete allows water to flow down to the subgrade.

37. Chapter 4 — Flatwork Pervious concrete requires an aggregate subbase or, in some cases of relatively impermeable subgrade, a subsurface drainage system.

38. Chapter 4 — Flatwork Either a vibratory roller screed or vibratory truss screed is used to strikeoff and level pervious concrete.

39. Chapter 4 — Flatwork A specialized joint roller is used to cut joints in fresh pervious concrete.

40. Chapter 4 — Flatwork A floor-profiling device such as a Dipstick ® measures random traffic floors requiring F-numbers, determining the F F and F L values of the floor.

41. Chapter 4 — Flatwork Finishing operations are critical in determining the final flatness numbers a floor can achieve.

42. Chapter 4 — Flatwork

43. Specified F-numbers refer to overall floor values; local F-numbers refer to individual sections of the floor.

44. Chapter 4 — Flatwork To produce superflat floors, a laser screed uses two independently mounted laser receivers to continuously monitor the screed head elevation.

45. Chapter 4 — Flatwork A floor profilograph measures the flatness of a floor by sensing irregularities in the floor surface.

46. Chapter 4 — Flatwork The floor must be re-straightedged after floating a hardener into surface.