What should be ensured about the tamping rod when rodding each layer?

The correct focus when rodding each layer of concrete is that the tamping rod should penetrate only the top concrete. This ensures that the rod effectively consolidates the concrete within the layer being compacted without disturbing the layers below. Proper penetration is essential to eliminate air pockets and achieve a uniform density throughout the layer, which contributes to the overall quality and strength of the completed concrete.

Choosing to allow the rod to penetrate only the surface avoids disturbing the integrity of the already compacted layers beneath. It is key to maintaining the structural simplicity and strength of the concrete mix.

In practicing correct techniques, considerations such as removing the rod after each layer do not apply, as this would disrupt the required compacting action. Impacting the mold sides is not a necessary action, as effective consolidation can be achieved through proper penetration techniques. Similarly, while a tamper rod bending is not ideal, it is not the primary focus during each layer of compaction when contrasted with ensuring proper penetration.