1.7. Vibrating Screed

Try these first

1. 1.

   What is the primary purpose of a surface vibrator?

   Hint

   Think about how vibrations help concrete.

2. 2.

   What is screeding?

   Hint

   Consider the term 'screed.'

3. 3.

   What is the effective depth for vibrations using surface vibrators?

   • 50 mm
   • 150 mm
   • 300 mm

   Hint

   Consider how deep the vibration needs to penetrate.

4. 4.

   True or False: Surface vibrators are suitable for concrete with a workability above 75 mm.

   • True
   • False

   Hint

   Think about the implications of high workability on concrete.

5. 5.

   Design a concrete slab requiring both surface vibrators and internal vibrators. Determine the thickness, workability, and reinforcement needs appropriate for each.

   Hint

   Consider the limitations on slab thickness and reinforcement density.

6. 6.

   Evaluate a scenario where using a vibrating screed resulted in accidentally using it on a high workability mix. What issues might arise, and how could they impact the project?

   Hint

   Relate risks of segregation to foundational problems in structures.