Which method is suitable for compacting medium- to high-slump concrete?

The appropriate method for compacting medium- to high-slump concrete is spading. This technique is effective for this type of concrete because it involves using a tool to push or pull the concrete around, which allows for the removal of air bubbles and enhances the density of the concrete mix. Given that medium- to high-slump concrete tends to be more fluid, spading can help in ensuring that the material flows into the forms properly while still consolidating the concrete effectively to achieve a strong, durable finish.

In contrast, while vibrating is commonly used for consolidating concrete, it may not be ideal for high-slump mixes because excessive vibration can lead to segregation of the aggregates. Rolling is generally more suited for thicker or denser materials and may not effectively compact high-slump concrete. Sliding lacks the specific action needed to facilitate proper consolidation in concrete work. Each method has its strengths, but for medium- to high-slump concrete, spading is the most suitable choice to achieve the desired compaction.