What is the primary function of a screed board vibrator?

To simultaneously level (screed) and compact the top layer of freshly placed concrete, making it suitable for large flat areas like floors and pavements.

What is the maximum depth of concrete a screed vibrator can compact?

It is generally effective for compacting concrete up to a depth of 150 mm (Clause 5.1).

Should internal vibrators be used along with screed vibrators?

Yes, for concrete thicknesses greater than the effective depth of the screed vibrator (150 mm), internal vibrators should be used first to compact the lower layers.

IS 11993

: 1987

Code of practice for the use of screed board concrete vibrators

CurrentSpecializedCode of PracticeStructural Engineering · Cement, Concrete, Aggregates and RCC

Download PDF BIS Portal Google

This code of practice provides guidance on the use of screed board concrete vibrators for compacting and finishing concrete surfaces like slabs and pavements. It covers the types of vibrators, operational procedures, effects on concrete properties, and essential maintenance practices.

Code of practice for the use of screed board concrete vibrators

Quick Reference Values

Effective depth of compactionup to 150 mm

Recommended speed of travel0.5 to 1.5 m/min

Typical reduction in entrained air0.5 to 1.5 percent

Frequency range of vibration (mechanical)3000 to 4000 vibrations/min

Suitability for concrete slumpRelatively stiff mixes

Practical Notes

Ensure the concrete has an appropriate slump; screed vibrators are most effective on stiffer mixes that cannot be manually compacted.

Avoid over-vibration, which can cause segregation of aggregates and bring excessive laitance to the surface, weakening the top layer.

The speed of travel is critical; moving too fast results in poor compaction, while moving too slow can lead to over-vibration and surface defects.