ACI Concrete Field Testing Technician - Grade I Practice Exam

When rodding the middle and top layers, how far should the tamping rod penetrate into the layer below?

1. 1/2 in.

2. 1 in.

3. 2 in.

4. 3 in.

The correct answer is: 1 in.

The correct answer is that the tamping rod should penetrate into the layer below by 1 inch when rodding the middle and top layers of concrete. This depth is essential for ensuring proper consolidation of the layers and achieving a uniform mix. By penetrating 1 inch into the underlying layer, you allow for adequate bonding and displacement of the aggregates, which helps eliminate air pockets and ensures that the layers adhere properly to one another. This technique is part of the standard practices outlined in concrete testing procedures, ensuring that the sample reflects the true properties of the concrete mix in question. Properly consolidating the concrete this way contributes to the overall strength and durability of the final product.