12.1. Key Rheological Parameters

Try these first

1. 1.

   What is yield stress in SCC?

   Hint

   Think about what it takes to make concrete start moving.

2. 2.

   Define plastic viscosity in your own words.

   Hint

   Consider how water behaves differently than honey.

3. 3.

   What is the yield stress in self-compacting concrete?

   • A moderate stress to allow flow
   • Minimum stress needed to initiate flow
   • Maximum stress after placement

   Hint

   Think about what is necessary to start the movement of a thick liquid.

4. 4.

   True or False: Plastic viscosity and yield stress are the same.

   • True
   • False

   Hint

   Consider how flow characteristics differ when liquid is already moving.

5. 5.

   If the yield stress of SCC is too high, what modifications can be systematically applied to reduce it?

   Hint

   Consider how making the mix more fluid can lower the resistance to flow.

6. 6.

   Discuss the implications of thixotropy in SCC when designing for structures with complex shapes.

   Hint

   Think about how shape stability impacts visual appearance and structural integrity.