11.1. Types of Admixtures Relevant to Fresh Concrete

Try these first

1. 1.

   What is the primary function of plasticizers in concrete?

   Hint

   Think about how they help in mixing.

2. 2.

   Define what a retarder does.

   Hint

   Consider the conditions they are used for.

3. 3.

   What is the primary purpose of using plasticizers in concrete?

   • Increase water content
   • Enhance workability
   • Delay setting time

   Hint

   Consider what happens to the workability when plasticizers are added.

4. 4.

   True or False: Retarders speed up the setting time of concrete.

   • True
   • False

   Hint

   Think about their use in hot weather.

5. 5.

   Design a concrete mix for a large outdoor slab that needs to cure under low temperatures yet maintain workability during transport. Justify your choice of admixtures.

   Hint

   Consider the temperature and the challenges that may arise during mixing and curing.

6. 6.

   Analyze the benefits and drawbacks of using air-entraining agents in high-strength concrete intended for bridge construction.

   Hint

   Think about the trade-offs between durability and strength in construction.