ACI Certification Practice Exam

When rodding the second and third layers, the rod must penetrate the previous layer approximately how much?

1. 0.5 inches

2. 1 inch

3. 1.5 inches

4. 2 inches

The correct answer is: 1 inch

When rodding the second and third layers of concrete, it is essential for the rod to penetrate the previous layer by about 1 inch. This penetration is crucial because it helps to bond the layers together, ensuring a strong and cohesive final product. Insufficient penetration can lead to weak points between the layers, potentially compromising the integrity of the poured concrete. The 1-inch penetration strikes a balance between providing adequate bonding without risking damage to the layers or creating air pockets. If the rod penetrated too shallow, there wouldn't be enough contact between layers; conversely, too deep penetration could disturb the layers excessively, leading to inconsistencies. Thus, the 1-inch guideline reflects best practices in achieving optimal consolidation and strength in layered concrete applications.