G9 Flashcards
What is the purpose of the backer rod?
Support caulking and maintain a thin bead of elasticity
What types of materials are used for backer rods?
Closed cell foam, rubber, neoprene
What tools are required for the installation of caulking?
Fun, applicator
7 steps used to install caulking.
Clean, mask, prime, backer rod, caulk, took joint, remove tape
What shape is the tooled surface of a caulking joint?
Hourglass
What type of caulking should have the area to be caulked cleaned with vinegar prior to application?
Silicone
Two types of rubber-based caulking.
Polysulfide and Butyl
Which caulking can be cleaned up with water before it cures?
Acrylic
Which caulking should not be used with polystyrene?
Polyurethane
List two types of caulking that can be painted.
Acrylic and Butyl
How are slip forms held together?
Yoke
What types of buildings are built with the slip-form method?
- Tall uniform structures
- Elevator shafts
- Water towers
At what rate are vertical slip-forms moved?
8”-18” per hour
Where is the finishers scaffold on a slip-form construction?
Below and Outside.
What depth of the layers is used when placing concrete?
12”
How are curved walkers built?
3 pieces of lumbe laminated together with offset joints.
What is the what is the purpose of a finishers scaffold?
Repair and touch up.
In mass concrete applications, how are the panel aligning bolts used?
Line up panel frames at the lower end of the frame.
What is the concern when designing the concrete for a gravity Dam?
Heat of hydration and cost.
Why is the concrete a different strength at the exposed faces of a gravity dam?
For durability.
What is used to help cool a gravity dam?
Cooling pipes.
Why is the concrete placed in blocks in a gravity dam?
To minimize shrinkage cracks.
What does a massive footing have in common with a gravity dam?
Large size
What is done to reduce the cost of a concrete mixture?
Less cement per cu. M. large, well graded aggregate, fly ash.
Explain the process of pre-stressing concrete beams.
Cables are placed and either pre or post-tensioned.
How does prestressing a concrete beam affect the strength of the beam?
Much stronger.
During the tensioning process, what forces are applied to the concrete beam?
Compression
What type of stress is reinforcing steel used to resist?
Tension
What is the maximum compressive force that a concrete sample can resist if it could resist a tensile force of 500lbs?
5000 lbs (1:10)
2 reasons why traditional reinforced concrete will deflect?
Rebar stretching and bond slipping.
Purpose of tie downs.
Create a curve for uplift.
What is used to tension a pre-stressing tendon?
Hydraulic jack
