7.7. Field Problems and Troubleshooting in Fresh Concrete

Try these first

1. 1.

   What does segregation mean in concrete?

   Hint

   Think about what happens when you see different colors or sizes in a concrete mix.

2. 2.

   What is bleeding in fresh concrete?

   Hint

   Consider what happens when a drink sweats on a hot day.

3. 3.

   What is the primary cause of segregation during concrete pumping?

   • Under-vibration
   • Over-vibration
   • Insufficient cement

   Hint

   Think of how stirring too much can cause things to separate.

4. 4.

   True or False: High ambient temperatures can accelerate the loss of slump in concrete.

   • True
   • False

   Hint

   Consider how heat affects other materials.

5. 5.

   A construction site reports frequent segregation during pumping despite using standard practices. Propose a multi-faceted approach to identify the cause and improve the situation.

   Hint

   Consider every step of the process from mixing to application.

6. 6.

   Your team is tasked with preparing a concrete mix for a bridge in a hot climate. What steps will you take to ensure the concrete maintains workability during transport?

   Hint

   Reflect on how temperature affects other materials.