Concrete Flashcards
What is the typical drying time for concrete?
28 days
What is the chemical process for concrete curing?
Hydration
What is considered the “normal” concrete type
Type I Portland Cement
What is Type IA concrete?
Normal concrete, air entrained
What is ‘Air Entraining’?
Tiny bubbles introduced into concrete to help with freeze/thaw cycle
Make concrete more workable
What percentage of air entrained concrete is bubbles?
5%
Where is Type IA concrete typically used?
Cold climates, exposed concrete and mixed climates
What is Type II concrete?
Moderate resistance to sulfates
Where is Type II concrete used?
Below ground when in contact with soil (in particular soil with high sulfate groundwater)
What is Type IIA concrete?
Moderate resistance to sulfates & air entraining
What is Type III concrete?
High early strength concrete
When is Type III concrete used?
Precast concrete - want it cured and out of the factory ASAP
Concrete Block factories, tilt-up construction, anywhere we want to strip formwork early
Also used in cold weather
What is Type IV concrete?
Low heat of hydration
When is Type IV concrete used?
Not often, more for larger structures like dams
What is Type V concrete?
High resistance to sulfate attachedW
What is decorative cement called?
White portland cement
How large should aggregate be in a concrete mix?
Less than 3/4 spacing of the rebar spacing
1/3 depth of the slab
What makes pervious concrete?
Aggregate of the same size
When is lightweight aggregate used in construction?
When a lighter weight is required and/or higher thermal resistance is required
What is used in structural lightweight concrete?
Expanded shale
What is used in non-structural lightweight concrete?
Large air entraining. It’s lighter, a better insulator but lower strength
What defines the strength of concrete?
Water content
What’s the range of PSI of concrete?
2,000 PSI to 20,000 PSI
Normal Concrete -> 3,000 to 4,000 PSI
What are ways of testing concrete strength?
Slump Test
Cylinder Test
