ACI Concrete Field Testing Technician - Grade I Practice Exam

Which of the following sampling methods is not covered by ASTM C1064?

1. Revolving drum mixers

2. Open top mixers

3. Forced action mixers

4. Paving mixers

The correct answer is: Forced action mixers

The correct answer indicates that forced action mixers are not covered by ASTM C1064. This standard focuses on the sampling of fresh concrete, primarily addressing commonly used mixing methods and their associated sampling techniques. The reason this answer is accurate lies in the specific scope of ASTM C1064, which provides guidelines for sampling fresh concrete from different types of mixers. While the standard mentions revolving drum mixers, open top mixers, and paving mixers—methods that are commonly employed in concrete mixing—forced action mixers are a more specialized type. These mixers operate differently and may require distinct methods for sampling that are not addressed within the scope of ASTM C1064. Understanding the limitations of standards is crucial for proper compliance and ensuring the integrity of sampling in concrete testing. By recognizing that forced action mixers fall outside the coverage of ASTM C1064, it highlights the importance of consulting additional standards or guidelines specific to that type of mixer for accurate sampling procedures.