and Equipment Chapter 6 Chapter Topics Spreading tools Consolidation or vibrating tools Laserguided screeds Hand screeding tools Tools for smoothing after screeding Jointing and edging tools ID: 719118
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Slide1
Placing and Finishing Tools and Equipment
Chapter 6Slide2
Chapter Topics
Spreading toolsConsolidation or vibrating toolsLaser-guided screeds
Hand screeding tools
Tools for smoothing after screeding
Jointing and edging tools
Hand floats and trowels
Power floats and trowels
Power sawsSlide3
Spreading Tools
Amount of hand work needed depends on:Concrete being placed close to the desired location
Tools for hand spreading include:
Short-handled, square-end shovels
Come-alongs
Concrete rakesSlide4Slide5
Consolidating or Vibrating Tools
Consolidation removes the entrapped air, producing concrete with the properties normally expected and desired for concrete slabs.
Equipment for consolidation of slabs:
Internal vibrators
Surface vibrators
Vibrating screeds
Vibratory roller screeds
Laser-guided screedsSlide6Slide7Slide8Slide9
Hand Screeding Tools
Screeding or strikeoff is sometimes done manually with a straightedge consisting of a rigid, straight piece of wood or metal.
Several
types of manually operated straightedges including hollow magnesium straightedges made especially for screeding.
Short straightedges are usually made of either wood or magnesium, whereas longer ones are made of steel angles or channels.
Some straightedges are built in such a way that they can be adjusted to provide a crown (or camber) to the surface.Slide10
Tools for Smoothing After Screeding
Bullfloats used for F
F
20 or less
handle with large piece of wood or metal
attached
Highway straightedges
used for F
F
greater than 20
6 to 12 ft long rectangular metal
straightedge
Darbies
long, hand-held floats used in congested areasSlide11Slide12Slide13Slide14
Jointing and Edging Tools
EdgersMake neat round edges less likely to chip or spall.
Various hand-held sizes and shapes; walk-behind.
Jointers (Groovers)
A cutting edge that makes a narrow groove.
The groove (contraction joint) produces a weakened section that helps cracks appear below the neat, straight joints.
Groove depth should be ΒΌ slab thickness.Slide15Slide16Slide17
Hand Floats
Used to remove small imperfections and produce a level, plane surface and prepare surface for troweling
Type of hand floats
Wood
Magnesium
Composition
Wood used for non-air-entrained and high-slump concrete
.
Magnesium used for air-entrained and lightweight concrete.Slide18
Hand Trowels
Used in final stages of finishing, after floating, to create hard and dense surface.As surface hardens, subsequent trowelings are done with smaller trowels to increase pressure on surface.
Fresnos are large, long-handled trowels used to smooth the slab quickly but does not provide a hard, dense surface.Slide19Slide20Slide21Slide22
Power Floats and Trowels
MachinesWalk-behind (3 ft to 4 ft ring diameter)
Riders (6 ft to 10 ft wide
)
Blades/attachments
Float blades or shoes: wider than trowel blades
Trowel blades: narrowest blades
Combination blades: for floating and troweling
Pans: circular disks attached blades Slide23Slide24Slide25Slide26Slide27
Power Saws
Dry-cut and wet-cut saws with an abrasive or diamond blade to cut contraction joints in large concrete surfaces.Dry-cut saws
Lighter than wet-cut saws
Permit joint sawing within 1 to 4 hours after finishing
Wet-cut saws
Can cut deeper joints
Joints sawed later than 4 hours after finishingSlide28
End of Chapter 6