Canadian Council of Independent Laboratories (CCIL) Practice Exam 2025 – 400 Free Practice Questions to Pass the Exam

Capping concrete samples is a method used to create a smooth, uniform surface for testing compressive strength. The chosen method aids in ensuring the accuracy of test results by addressing any imperfections on the sample's ends that may impact the measured strength.

Capping is generally suitable for concrete strengths up to 70 MPa without the need for grinding. Beyond this limit, the surface irregularities and hardness of the concrete can lead to inaccuracies in the test results, necessitating additional preparation through grinding to ensure that the ends of the sample are flat and parallel.

For strengths exceeding this threshold, the risk of not achieving a proper capping becomes significant, as higher strength concrete tends to be more challenging to cap uniformly without additional measures. Therefore, the recognition that 70 MPa is the maximum suitable strength reinforces the importance of preparing samples for accurate testing in accordance with industry standards.