19.1. Fresh Concrete Behavior

Try these first

1. 1.

   What is fresh concrete?

   Hint

   Think about the state of concrete before it hardens.

2. 2.

   Define workability in concrete.

   Hint

   Consider how easy it is to work with concrete materials.

3. 3.

   What effect does increased water absorption in recycled aggregates have on workability?

   • Increases workability
   • Decreases workability
   • No effect

   Hint

   Think about how hydration affects other materials.

4. 4.

   True or False: The surface texture of recycled aggregates does not influence the amount of paste needed in concrete.

   • True
   • False

   Hint

   Consider how different surfaces interact with liquids.

5. 5.

   Given a concrete mix design using 100 kg of recycled aggregates with a water absorption of 10%, how would you adjust the water content to maintain workability?

   Hint

   Consider how much water the aggregates would absorb and add that into your equation for the overall water needed.

6. 6.

   Evaluate how using a higher proportion of rough recycled aggregates could affect the overall concrete performance and suggest ways to counter these effects.

   Hint

   Think about how to balance texture and paste in your mix design.