12. Surface Vibrators
The chapter discusses the various types of concrete vibrators and finishing techniques for achieving optimal concrete consolidation and surface quality. It highlights the differences between internal and surface vibrators, their effective applications, and the importance of proper finishing stages to prevent harm to concrete strength. Additionally, it explains guidelines for using different vibration methods based on concrete consistency.
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What we have learnt
- Surface vibrators consolidate concrete from the top down, while internal vibrators are more effective but may not be suitable for thin or densely reinforced slabs.
- Surface vibrators should not be used on high workability mixes above 75 mm slump to avoid segregation and surface weakness.
- Finishing operations, including screeding, floating, and troweling, should be timed appropriately between the initial and final setting of concrete to maintain surface integrity.
Key Concepts
- -- Internal Vibrators
- Devices that provide direct vibration to the concrete, typically more effective for consolidation compared to surface vibrators.
- -- Surface Vibrators
- Vibrators that work by applying vibration at the surface to consolidate concrete; they are used when internal vibrators are not feasible.
- -- Segregation
- The separation of water and fines from the concrete mix, leading to weak surface layers, often resulting from improper vibration techniques.
- -- Finishing Stages
- The sequence of operations (screeding, floating, and troweling) performed on concrete to achieve the desired texture and surface quality.
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