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

The required penetration depth for internal vibration in a mould is crucial for ensuring that the concrete mix is adequately compacted and free of air voids. In this case, with a mould that measures 150mm x 300mm, the standard practice is to establish the optimal penetration depth for the internal vibrator based on the dimensions of the mould and the characteristics of the concrete being used.

A penetration depth of 25mm is considered appropriate because it allows for effective vibration that can adequately consolidate the concrete throughout the thickness of the mould. This depth ensures that the vibrations can propagate sufficiently within the mix, achieving the intended density and integrity while avoiding issues such as segregation or excessive air entrapment.

Choosing a depth less than this might not adequately mobilize the particles within the concrete mix, while opting for a deeper penetration may lead to over-vibration, which can also negatively impact the concrete’s structure. The 25mm depth strikes a balance to ensure thorough and efficient vibration, especially in a mould of this size, making it the correct choice.