Which category requires mixing and re-testing for compliance?

• A. Structural Concrete.
• B. Recycled Concrete.
• C. Decorative Concrete.
• D. Non-Structural Concrete.

Answer: (D)

The main idea is how testing and remediation are treated for different concrete categories. Mixing and re-testing to demonstrate compliance is allowed for non-structural concrete because it doesn’t affect a structure’s load-bearing performance. If a sample or batch doesn’t meet the spec, the contractor can adjust the mix and re-test to prove compliance without risking structural integrity. For structural concrete, repairs like remixing after a test failure aren’t typically permitted, since any change could alter strength and durability and would require more formal requalification. Decorative or recycled concrete involve other considerations (appearance, material variability, or recycled content) and aren’t the category that routinely permits this remix-and-retest path. Therefore, non-structural concrete is the category where mixing and re-testing for compliance is the standard approach.