ACI Concrete Field Testing Technician - Grade I Practice Exam

The correct answer is based on the standards outlined by ASTM, which plays a crucial role in ensuring consistency and reliability in testing materials. Specifically, ASTM C29 covers the methods for determining the bulk density (unit weight) and voids in aggregate. This is relevant when discussing measures used in concrete testing, including air content determination.

When conducting tests for measuring air content in concrete, the basic equipment typically includes an air meter bowl. However, if alternative measures or methods are employed, it is essential that those methods meet the standards stipulated in ASTM C29 to ensure accuracy and comparability of results. This is critical for obtaining valid measurements that conform to the industry's quality expectations.

The other standards listed do not pertain to the alternative measures for air content testing. ASTM C25 focuses on the density, specific gravity, and absorption of aggregates, ASTM C30 covers the evaluation of the air content of fresh concrete, and ASTM C31 deals with making and curing concrete test specimens in the field. Each of these has its own focus and application, but they do not specifically address the requirements for measures other than air meter bowls in the context of air content testing.