What method of consolidation should be used when the slump is greater than 3 inches?

When the slump of concrete exceeds 3 inches, rodding is the recommended method of consolidation. This is because a higher slump indicates that the concrete is relatively fluid and workable, making it easier to consolidate without the risks of segregation that can occur with more aggressive methods. Rodding involves inserting a rod into the concrete mix and gently stirring it to eliminate air bubbles and ensure that the mix is evenly distributed.

In situations where the slump is high, rodding provides the necessary consolidation while maintaining the integrity of the mix. This method allows for sufficient compaction while preventing excessive movement that could lead to the separation of coarse and fine aggregates.

Other methods like vibration might introduce too much energy into the mix, which could cause segregation of the materials. Stamping and tamping, while effective for certain applications, are generally better suited for lower slump concrete, where more effort is needed to achieve adequate consolidation.