What is the significance of moisture content in aggregates used for FDOT concrete?

• A. It only affects curing time.
• B. Aggregates must have known moisture to adjust batch water; incorrect moisture leads to wrong slump or strength.
• C. It has no effect on mix.
• D. Moisture content only affects color.

Answer: (B)

Moisture in aggregates directly changes how much water ends up in the concrete mix. The batch water you set is meant to hit a target slump and a given water-cement ratio, but water already present in the aggregates counts toward that total. If you don’t know and account for the aggregate moisture, you’ll either add too much water (raising slump and lowering strength) or too little (producing a stiff mix and potential strength loss). That’s why knowing moisture and adjusting batch water accordingly is essential for achieving the desired workability and strength. The other ideas—only curing time, no effect on the mix, or only affecting color—don’t reflect how moisture governs mix water, slump, and strength in FDOT practice.