Zone I (coarse sand) sand is suitable for high-strength concrete (≥ C50) or large volume concrete (reducing cement dosage and hydration heat).
Zone II (medium sand) has the widest applicability and can be used for C30~C60 concrete and pumped concrete (with easy control of fluidity).
Zone III (fine sand), suitable for low strength concrete (≤ C25) or scenarios requiring high water retention (such as thin-layer pouring), but the dosage needs to be controlled to avoid deterioration of workability due to excessive specific surface area.
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