ACI Concrete Field Testing Technician - Grade I Practice Exam

What must be done to the sample container before sampling the concrete?

1. Dry with a cloth

2. Dampen with water

3. Wash with soap

4. Insulate with foam

The correct answer is: Dampen with water

Dampening the sample container with water is essential before sampling concrete to prevent absorption of moisture from the concrete mix. When a dry container is used, it can draw out water from the concrete, disrupting the water-cement ratio and potentially altering the concrete's properties. This step ensures that the integrity of the sample is maintained, reflecting the true composition of the concrete mix being tested. Maintenance of consistent sampling conditions is crucial in field testing to obtain reliable results. If a container is dry, it may have an unintentional effect on the test results, causing inaccuracies in subsequent analyses. Therefore, dampening helps create an environment that mirrors the conditions of the concrete as closely as possible, ensuring better precision in the results.