The internal vibrator, also known as a vibrating bottle or bottle vibrator, is the most important tool for concrete consolidation in construction. The cylindrical device is immersed directly into fresh concrete and generates high-frequency vibrations (typically 12,000–18,000 rpm) that drive air pockets out of the concrete.
Consolidation by internal vibrators is critical for the strength and durability of concrete components. Uncompacted concrete can contain up to 30% air voids, which drastically reduces compressive strength. Modern internal vibrators are available in various diameters from 25 mm to 80 mm and are powered electrically, pneumatically, or by combustion engines.
In building construction and bridge engineering, they are used for foundations, columns, walls, and slabs. Immersion depth and duration must be carefully controlled: too short vibration leaves pores behind, while excessive vibration causes concrete segregation.