ACI Decorative Flatwork flashcards
ACI Decorative Flatwork · Build recall with a focused review session.
32 cards. Read the term and the definition here. The deck at the top of this page is optional.
- Stamp timing
- The point when concrete has stiffened enough that a stamp tool leaves a clean impression without mortar sticking, typically after bleed water disappears.
- Release agent
- Powder or liquid applied between the stamp and concrete so the tool does not adhere; excess is removed before curing and sealing.
- Integral color
- Pigment mixed into the concrete at the batch plant to color the entire slab; dosage is limited to avoid strength loss and efflorescence.
- Color hardener
- Dry-shake product broadcast onto the plastic surface in two passes and floated in to densify and color the top layer.
- Surface retarder
- Chemical sprayed on fresh concrete that keeps the top mortar green so it can be exposed by washing or brushing after the slab sets.
- Exposed aggregate
- Finish produced by retarder or mechanical abrasion that removes surface paste to reveal the aggregate beneath.
- Antiquing release
- Colored powder or liquid that adds accent tones in the joints and texture; it must be cleaned off before sealing.
- Control joint depth
- A contraction joint cut or tooled to at least one-quarter of the slab thickness to force cracking at a planned location.
- Joint spacing rule
- A common ACI guideline spaces contraction joints at roughly 24 to 36 times the slab thickness measured in inches.
- Slab thickness
- Decorative stamped flatwork is typically placed at a nominal 4 inches over compacted base, thickened where vehicle loads occur.
- Sealer application
- A protective coating applied to dry, clean decorative concrete to enhance color and resist moisture, stains, and abrasion.
- Broom finish
- A textured finish created by dragging a stiff broom across the surface to improve slip resistance on walks and drives.
- Trowel finish
- A smooth, dense finish produced by power or hand trowels; it is used where a reflective or polished appearance is desired.
- Salt finish
- Rock salt broadcast onto the plastic surface and later washed out leaves small pits that give a textured, non-slip appearance.
- Saw-cut timing
- Joints are cut as soon as the concrete can support the saw without raveling, usually within 4 to 12 hours after finishing.
- Form release
- A coating applied to forms so they release cleanly from the concrete and do not tear or stain the finished surface.
- Water-cement ratio
- The ratio of water to cementitious material by weight; lower ratios increase strength and durability and reduce shrinkage.
- Slump limit
- A measure of concrete workability; decorative flatwork mixes commonly specify a maximum slump near 4 inches.
- Air entrainment
- Tiny air bubbles intentionally entrained in concrete, typically 5 to 7 percent, to resist freeze-thaw damage in exterior flatwork.
- Curing duration
- ACI 308 recommends keeping concrete moist for at least 7 days after placement to allow strength gain and reduce cracking.
- Cold-weather placement
- Concrete should be maintained above roughly 40 to 50 F at placement and protected from freezing until adequate strength develops.
- Hot-weather precautions
- Cooling materials, placing during cooler hours, and using retarders reduce rapid moisture loss and plastic shrinkage cracking.
- Plastic shrinkage
- Cracking that occurs while concrete is still plastic when surface evaporation exceeds the bleed water supply.
- Evaporation rate
- The rate at which moisture leaves the concrete surface; values above about 0.1 lb per sq ft per hour favor plastic shrinkage cracking.
- Subgrade preparation
- The base is compacted, uniform, and moistened before placement to prevent uneven settlement and rapid moisture loss.
- Vapor retarder
- A sheet or coating under a slab on grade that limits moisture migration from the soil into the concrete and floor covering.
- Isolation joint
- A joint that separates flatwork from structures or other slabs so they can move independently without cracking.
- Construction joint
- A planned stopping place in a placement, often keyed or doweled as designed, where fresh concrete meets previously placed concrete.
- Dowel bar
- A smooth steel bar placed across a joint to transfer load while allowing longitudinal movement between adjacent slab sections.
- Consolidation
- Vibration or tamping of fresh concrete to remove entrapped air and ensure it fills forms and surrounds reinforcement.
- Bleed water
- Water that rises to the surface of fresh concrete as heavier solids settle; it must evaporate before finishing begins.
- Finishing sequence
- The order of operations after placement: screeding, bull floating, waiting for bleed water to leave, then floating and final texturing.