Aggregates and Moisture – Typical maximum surface water content in moist sand by mass.

Introduction:
Moist sand carries free (surface) water that affects batching by volume and workability. Estimating typical surface moisture helps adjust water content and sand bulking corrections.

Given Data / Assumptions:

• Fine aggregate is natural sand.
• State considered is moist, not oven-dry or fully saturated slurry.
• Mass-based percentage is requested.

Concept / Approach:

Surface moisture in sand commonly varies from about 2% to 8% by mass depending on grading and weather. A widely cited upper typical value for moist sand is around 7.5% before the material becomes obviously saturated.

Step-by-Step Solution:

Verification / Alternative check:

Field tests (bulking test in a jar) and periodic moisture content checks align with 5%–8% ranges; 7.5% is a reasonable upper typical value.

Why Other Options Are Wrong:

1.25% and 2.5% are too low for typical moist sand; 5% can occur but is not the upper typical value; 10% is higher than usual for ‘‘moist’’ and indicates very wet conditions.

Common Pitfalls:

Ignoring moisture corrections causing variable slump or strength; not recalibrating volumetric batching.

Final Answer:

7.5%