Canadian Council of Independent Laboratories (CCIL) Practice Exam 2025 - Free CCIL Practice Questions and Study Guide

The requirement for 20 strokes per lift when rodding a 100mm cylinder aligns with established standards for ensuring consistent and effective compaction of the concrete sample. The practice of rodding is crucial because it helps eliminate air pockets and achieves proper density within the mix, which is essential for accurate testing and results.

In this context, the specified number of strokes—20—provides an optimal level of compaction without overworking the concrete, which could alter its intended properties. This method is standard practice, ensuring that the material is adequately compacted to reflect real-world conditions without introducing variables that could affect strength and durability evaluations.

Understanding the rationale behind this number is vital for adherence to testing protocols, as lesser or greater amounts may lead to inconsistent results or misrepresentation of the material's characteristics. Therefore, 20 strokes is the recommended practice to achieve reliable and standard-compliant results when preparing a 100mm concrete cylinder for testing.