What role does the concrete mix design play in field inspection, and what materials are typically checked?

• A. It defines strength, workability, and durability; inspect cement type and amount, aggregate sizes, recommended air content, slump targets, and admixtures.
• B. It determines color and gloss of the surface only.
• C. It only specifies curing duration.
• D. It sets the maximum formwork pressure.

Answer: (A)

The mix design sets the expected performance of the concrete in terms of strength, workability, and durability, so field inspection focuses on whether the actual batch aligns with those targets. In practice that means checking the materials and fresh-concrete properties that the design specifies. You verify the cement type and amount to confirm the cementitious system and strength target are achieved. You review the aggregate sizes and grading to ensure the coarse and fine aggregates meet the specified maximum size and distribution for proper compaction and durability. You confirm the recommended air content to achieve the designed freeze‑thaw durability and air-void system. You compare the slump targets to ensure the batch will flow and consolidate correctly on site. And you check that any admixtures called for in the mix design are present and dosed as specified, including any supplementary cementitious materials, set accelerators or retarders, and water-reducing agents. These checks ensure the as-built concrete reflects the design intent and will perform as intended in the structure.