According to best practices, how should concrete be deposited to prevent segregation?

To prevent segregation in concrete, it is crucial to ensure a controlled and uniform deposition method. Using controlled directional discharge allows for the concrete to be placed in a manner that minimizes movement and disturbance, which helps maintain the homogeneity of the mix. This practice reduces the risk of the heavier aggregates settling at the bottom while the lighter cement paste rises to the top, a common issue known as segregation.

When concrete is deposited with a focus on controlled direction, it can be directed precisely where it needs to go, allowing for an even distribution that maintains the integrity of the mix. This technique is especially important in large pours or when working with specific placements in forms, where disturbances can lead to poor bonding and structural weaknesses.

In contrast, other methods such as free-falling from the mixer or pouring directly from the truck can lead to increased risk of segregation, as the concrete may drop from significant heights or be influenced by gravity in an uncontrolled manner. Layering with an internal vibrator, while beneficial for consolidating, may still pose risks if not accompanied by controlled placement techniques, as it can lead to over-vibration and displacement.

Thus, using a controlled directional discharge is essential for ensuring the quality and performance of the placed concrete.