ACI Concrete Strength Testing Technician Practice Test

What materials are suitable for plates used in neat cement and high-strength gypsum plaster caps?

1. Plastic, wood, composite, or aluminum

2. Glass, metal, granite, or diabase

3. Steel, ceramic, rubber, or foam

4. Concrete, gypsum, resin, or silicon

The correct answer is: Glass, metal, granite, or diabase

The use of appropriate materials for plates in neat cement and high-strength gypsum plaster caps is crucial for ensuring accurate compressive strength testing results. Glass, metal, granite, or diabase are particularly well-suited for this purpose because they possess characteristics that enhance the reliability and effectiveness of the testing process. These materials are durable and rigid, which helps maintain a stable support surface for the specimen being tested. Their lack of compressibility is vital, as it prevents any deformation during testing that could lead to inaccurate strength measurements. In addition, granite and diabase have low porosity, making them less likely to absorb moisture, which can affect the properties of the cement or gypsum being tested. While other materials in the other choices may have some applicable uses in construction or other non-testing scenarios, they may not provide the same level of precision and integrity required for strength testing. Ideally, the chosen materials should help facilitate a clear transfer of stress during the compressive strength tests, ensuring that the results reflect the actual performance of the cement or gypsum under standard test conditions.