Admixtures for Concrete


Quiz Questions

1. The following classifies as an admixture:
Cement
Water
Aggregates
Plasticizer
2. Admixture of any type or amount can be considered a substitute for good concreting practice.
True
False
3. Which of the following is false about air entraining admixtures?
Air entraining admixtures introduce and stabilize microscopic air bubbles in concrete
Air entraining admixtures improve the durability of concrete exposed to cycles of freezing and thawing
Air entraining admixtures increase fresh concrete segregation and bleeding
Air entraining admixtures are able to do all of the above
4. Typical water reducing admixtures are able to reduce the water content by:
1-3%
5-10%
10-15%
15-20%
5. The effectiveness of water reducers on concrete is a function of:
Chemical composition
Concrete temperature
Cement composition
All of the above
6. Which of the following is not an application where flowing concrete is used?
wide-section placements
Areas of closely spaced and congested reinforcing steel
Tremie pipe placements
Pumped concrete to reduce pump pressure
7. Calcium chloride _____ an antifreeze agent.
Is
Is not
8.

Calcium chloride or admixtures containing soluble chlorides ______________ in prestressed concrete.
Should always
Should not
9. Sound, dense concrete made with a water to cement ratio of __________ by mass will be watertight if it is properly placed and cured.
Greater than .5
Less than .5
Greater than .8
Less than .8
10. ___________ admixtures increase the cohesiveness of concrete to a level that allows limited exposure to water with little loss of cement.
Grouting
Gas forming
Antiwashout
Fungicidal