G7 - LT #1 Conc. Finishing Flashcards
What stages of finishing is an edger used and why?
1) After bull floating, pushes large aggregates AWAY from the surface
2) Rounds over
What is the purpose of hand floating and bull floating?
Pushes large aggregates down & allows bleed water to escape.
Is a divider tool deep enough for control joints?
No
When is the placing of the concrete completed?
After floating process
Why should bleed water be allowed to evaporate first?
1) Not to dilute the concrete
2) causes dusting and crazing if you do not
How to broom finish?
Float, edge, trowel, broom and edge again
When are screeds removed from the concrete?
After strike-off
What is the purpose of a screed?
Elevated guide for strike off
How is the top of a concrete wall finished?
Remove the cleats from formwork and then float
What is the purpose of kneed boards?
Distributes weight evenly
What tool is used to transfer flexible patterns?
Tamper
5 precautions to consider when finishing a concrete slab with a power trowel?
1) Concrete is flat & level
2) Will bear the pressure
3) bleed water is evaporated
4) cover entire surface uniformly
5) allow concrete to harden between passes
How is the movement of a power trowel controlled?
1) Increase RPM to engage blade rotation
2) Push down on handles to move right & lift up to move left
What is a burnished surface?
Mirror-like finish, made by making many passes with a power trowel at high speeds and a steep angle.
What are two different types of blades used with power trowels?
Float & Trowel
What safety precautions must be taken with concrete treatments?
Read the SDS Safety Data Sheet
What are the environmental concerns associated with concrete treatments?
Streams & groundwater
Describe how sealers and hardeners also act as a curing compound.
Coat the surface to stop moisture.
How is exposed aggregate wall surface created?
Uniform coat of retardant, painted on the forming material, don’t slide concrete surface of coated form & strip carefully
What is the difference between dampproofing & waterproofing materials?
Moisture vs. hydrostatic pressure
How is a suspended concrete slab waterproofed?
Membrane roofing
The top of a concrete wall that is left exposed must be finished with:
A steel trowel