2.3. Frequency and Amplitude Considerations

Try these first

1. 1.

   What is the primary limitation of using surface vibrators?

   Hint

   Think about the conditions where internal vibrators can't be used.

2. 2.

   Define vibration frequency in the context of concrete vibrators.

   Hint

   What do we measure in terms of how often a vibratory action occurs?

3. 3.

   What is the maximum effective depth for surface vibrators?

   • 100 mm
   • 150 mm
   • 200 mm

   Hint

   Remember the depth limit discussed.

4. 4.

   True or False: High frequency vibrations are more effective than low frequency for all concrete types.

   • True
   • False

   Hint

   Consider the characteristics of different concrete mixes.

5. 5.

   You are tasked with using a surface vibrator on a concrete slab that's 180 mm thick, but you find it difficult to achieve satisfactory consolidation. What factors might be influencing this situation?

   Hint

   Consider the tools’ limits and their ability to transfer vibration.

6. 6.

   You notice that after using a surface vibrator, the surface layer has segregated. Explain why this might have happened and how to prevent it in future projects.

   Hint

   Think about how workability correlates with the mixer behavior.