ACI Concrete Field Testing Technician - Grade I Practice Exam

What is the purpose of adding isopropyl alcohol to the air meter?

1. To measure air content

2. To cool the mixture

3. To dispel any foam that may be on the surface of the water

4. To enhance the color of the solution

The correct answer is: To dispel any foam that may be on the surface of the water

The addition of isopropyl alcohol to the air meter serves specifically to dispel any foam that may be present on the surface of the water. In air content testing, foam can interfere with the accurate reading of the air meter by creating an erroneous measurement that may not reflect the actual air content in the concrete mixture. Isopropyl alcohol acts as a surfactant, helping to reduce surface tension, which allows the foam to dissipate. This ensures that the measurement obtained is precise and reliable, reflecting the true air content of the concrete sample being tested. This clarity is crucial for quality control in concrete production, as air entrainment directly affects the durability and workability of the concrete.