Chapter 4 — Flatwork Common types of flatwork include concrete pavements, floors, and walkways.
Chapter 4 — Flatwork Concrete for one-way and two- way joist systems is placed as a single, continuous member with the girders and beams.
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.
Chapter 4 — Flatwork Floors are classified based on their final use.
Chapter 4 — Flatwork Commercial and residential driveways are built to standard widths.
Chapter 4 — Flatwork A driveway is sloped depending on site conditions, the size of the driveway, and final appearance desired.
Chapter 4 — Flatwork A drainage system is installed on driveways that slope toward a garage.
Chapter 4 — Flatwork Curbs and gutters are classified as barrier, which redirects a vehicle, and mountable, which allows a vehicle to cross over.
Chapter 4 — Flatwork Slipforming greatly reduces the labor required to form and place curbs and gutters.
Chapter 4 — Flatwork Site preparation requirements include excavating and compacting subgrade, setting forms, installing plumbing and electrical systems, and setting rebar.
Chapter 4 — Flatwork Print specifications detail form and reinforcement requirements.
Chapter 4 — Flatwork The welded wire fabric number provides information on wire spacing, size, and whether wire is smooth (W) or deformed (D).
Chapter 4 — Flatwork Chairs are made of steel, plastic, or precast concrete and support reinforcement material at the proper elevation.
Chapter 4 — Flatwork Rebar increases the tensile strength of concrete and can contain lugs to improve bonding with concrete.
Chapter 4 — Flatwork Rebar is held in place with wire ties used at intersecting points.
Chapter 4 — Flatwork Tie bars are used between concrete sections to connect multiple slab sections.
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.
Chapter 4 — Flatwork Proper dowel size and spacing must be used during concrete placement to ensure adequate concrete strength and to avoid cracking.
Chapter 4 — Flatwork Common formwork materials are dimensional lumber, aluminum alloy, and steel.
Chapter 4 — Flatwork Setting forms to the proper elevation is accomplished with a carpenter’s level, transit level, or string.
Chapter 4 — Flatwork Forms must be properly set to ensure a level concrete slab.
Chapter 4 — Flatwork Screed systems are made of metal or wood and level concrete to the proper elevation.
Chapter 4 — Flatwork Placement should start at the point farthest from the concrete supply and work in continuous strips back toward the concrete supply.
Chapter 4 — Flatwork Placement, consolidation, and finishing procedures are completed simultaneously on different sections of fresh concrete.
Chapter 4 — Flatwork When a load is applied, compressive and tensile forces generate internal stresses resulting in cracks in the concrete.
Chapter 4 — Flatwork Two commonly-used types of control joints are sawed and tooled.
Chapter 4 — Flatwork Tooled control joints are useful for small slabs, such as a sidewalk.
Chapter 4 — Flatwork An alternative to hand-tooled control joints is to embed preformed metal or plastic strips into concrete.
Chapter 4 — Flatwork Control joint spacing is determined by the depth of the slab.
Chapter 4 — Flatwork Expansion joints are used at the juncture of two concrete components to allow concrete the freedom to move.
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.
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.
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.
Chapter 4 — Flatwork Pervious concrete allows water to flow down to the subgrade.
Chapter 4 — Flatwork Pervious concrete requires an aggregate subbase or, in some cases of relatively impermeable subgrade, a subsurface drainage system.
Chapter 4 — Flatwork Either a vibratory roller screed or vibratory truss screed is used to strikeoff and level pervious concrete.
Chapter 4 — Flatwork A specialized joint roller is used to cut joints in fresh pervious concrete.
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.
Chapter 4 — Flatwork Finishing operations are critical in determining the final flatness numbers a floor can achieve.