# Concrete Vibrator (Needle Vibrator)

> A concrete vibrator, also called a needle vibrator, drives trapped air out of wet concrete. See a slab pour example and the pre-pour checklist.

Canonical: https://superwise.site/glossary/vibrator-concrete/
Last updated: 2026-11-01

A mechanical tool whose vibrating steel needle is pushed into wet concrete to drive out trapped air and compact the mix.

## What is Vibrator (Needle Vibrator)?

A needle vibrator is a mechanical tool, also called a concrete vibrator, that compacts wet concrete in [formwork](https://superwise.site/glossary/formwork/), and using one is mandatory in structural work. Concrete poured into a deep form such as a column traps air pockets. The operator pushes the high-frequency metal needle into the mix, and the vibration liquefies the mortar, drives the air to the top and lets the concrete flow around the dense grid of [rebar](https://superwise.site/glossary/reinforcement-rebar/).

## Practical example

During a roof slab pour, the vibrator breaks down. The [site engineer](https://superwise.site/glossary/site-engineer/) orders the concrete pumps to stop at once. If the pour continued without vibration, the hardened concrete would hold internal air voids and severe [honeycombing](https://superwise.site/glossary/honeycombing/) on the underside, and the slab could not carry its design load.

## In SuperWise

In SuperWise a pre-pour checklist can include a yes or no line such as "Are 2 working needle vibrators on the slab?", next to photo and signature fields. A checklist can be set as the start or finish checklist of a task, and a task with an enforced checklist cannot be marked complete until the checklist is approved.

[Quality and safety checklists](https://superwise.site/features/construction-quality-safety/)

## Related terms

- [Honeycombing (Concrete Defect)](https://superwise.site/glossary/honeycombing/)
- [Reinforcement (Rebar)](https://superwise.site/glossary/reinforcement-rebar/)
- [Formwork (Shuttering)](https://superwise.site/glossary/formwork/)
- [Site Engineer](https://superwise.site/glossary/site-engineer/)

## Related
- [Honeycombing (Concrete Defect)](https://superwise.site/glossary/honeycombing/)
- [Reinforcement (Rebar)](https://superwise.site/glossary/reinforcement-rebar/)
- [Formwork (Shuttering)](https://superwise.site/glossary/formwork/)
- [Site Engineer](https://superwise.site/glossary/site-engineer/)
- [Quality and safety checklists](https://superwise.site/features/construction-quality-safety/)