4.4. Selection of Admixtures – Practical Considerations

Try these first

1. 1.

   What is an admixture in concrete?

   Hint

   Think about what can change how concrete behaves.

2. 2.

   Name one function of superplasticizers.

   Hint

   How can we make concrete easier to work with?

3. 3.

   Which admixture is used to accelerate the setting time of concrete?

   • Retarder
   • Superplasticizer
   • Accelerator

   Hint

   Think about the word 'speed' in terms of setting time.

4. 4.

   True or False: Air-entraining agents are used to enhance the workability of concrete.

   • True
   • False

   Hint

   What is the primary function of air-entraining agents?

5. 5.

   A large concrete pour is scheduled for a bridge deck on a hot day. Discuss how you would choose admixtures to ensure quality.

   Hint

   Think about how weather affects concrete behavior.

6. 6.

   Explain how using superplasticizers can impact the durability of a high-rise structure's concrete.

   Hint

   Consider how water content affects strength.