Which category requires mixing and re-testing for compliance?

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

Answer: (C)

The key idea is that some concrete categories allow a batch to be salvaged by re-mixing and re-testing to prove it meets the spec. For non-structural concrete, this rework is commonly permitted because the consequences of noncompliance are less critical to safety, so the QA process often includes a pathway to re-mix a batch and verify compliance through retesting rather than discarding it outright.

In contrast, structural concrete carries critical load-bearing requirements, so the focus is on meeting strength and durability specs on the first pass, with less emphasis on reworking the batch to salvage it. Decorative and recycled concrete have their own specialized testing and acceptance rules that don’t center on re-mixing for compliance in the same way.

So, non-structural concrete is the category where mixing and re-testing to demonstrate compliance is the standard approach.