Concrete unit 69-carp 4
Water stop
A ___ is a PVC, rubber or stainless steel barrier used to prevent the passage of liquid or gas under pressure through a joint in a concrete slab or wall
Sealant
A ____ is used to prevent air and water from passing through an expansion joint and into a building
Backer rod
A _____ is first forced into the expansion joint to limit the depth of the sealant
Lift
A layer or concrete is also known as a ___
Extends through the slab
An expansion joint in a concrete slab ___
Cement
Concrete is a mixture of ___, fine or course aggregate, and water
28
Concrete samples used to determine compression strength are cured for ___ days
Tower
Freestanding or climber ____ cranes are used to transport concrete to upper levels in concrete buckets
Water to cement ratio
The compression strength of concrete is largely dependent upon its ___
4' to 6'
The maximum free fall distance of concrete is ___
Cold temperatures
What type of conditions are air entraining admixtures used for?
A straightedge on screed rails
While concrete is being placed, cement finishers strike off the concrete with ____
Air entraining
____ admixtures produce microscopic air bubbles in a concrete mixture
