What is a precaution when using vibration for consolidation?

Using vibration for consolidation in concrete applications is a common practice, but it comes with certain precautions. One significant precaution is that over-vibration can lead to segregation of the concrete mix. When concrete is vibrated excessively, the heavier aggregates can settle to the bottom while the lighter components, such as water and finer particles, rise to the surface. This separation can compromise the uniformity and strength of the concrete, ultimately affecting the structural integrity of the finished product.

The other options present considerations that might seem relevant but are not as crucial in the context of vibration consolidation. For instance, while it is true that low slump mixtures can benefit from vibration, it is not an absolute requirement for all cases. The use of a special type of mallet is not standard for vibration; mallets are more commonly associated with handling or forming tasks. Lastly, while larger aggregates might complicate the process, vibration can still be effective with larger aggregates, as long as the vibration technique is appropriately adjusted. Thus, the focus on segregation as a risk of over-vibration highlights a key aspect of working safely and effectively with vibration in concrete consolidation.