ACI Concrete Strength Testing Technician Practice Test

Which type of pads can be used on concrete with compressive strength between 1500 and 6000 psi without qualification?

1. Neoprene pads with a durometer hardness of 60

2. Polyurethane or butyl pads with a durometer hardness of 50

3. Only bonded cushions

4. Any unbonded pad

The correct answer is: Polyurethane or butyl pads with a durometer hardness of 50

The use of pads in concrete strength testing is crucial for obtaining accurate results, particularly when dealing with varying levels of compressive strength. In this case, polyurethane or butyl pads with a durometer hardness of 50 are suitable for concrete with compressive strengths ranging from 1500 to 6000 psi without qualification. Polyurethane pads are known for their durability and ability to provide a uniform load distribution, which is essential in strength testing. Their durometer hardness of 50 provides a good balance between firmness and flexibility, allowing for optimal contact with the test specimen while minimizing the risk of yielding or affecting the test outcome. This specific hardness level is designed to accommodate the compressive strengths indicated, ensuring reliable measurements during testing. Additionally, when testing concrete with this range of strengths, it is important to ensure that the pads can withstand the pressure without excessive deformation. The specified type and hardness of pads meet those requirements, making them appropriate for the intended use. Other options, such as neoprene pads with different hardness levels, or unbonded pads without specific qualifications, may not offer the same level of performance for the specified range of concrete. Therefore, using polyurethane or butyl pads with the noted hardness ensures compliance with testing standards and improves the reliability of strength