The amount of free water used in concrete shall not exceed ____________ pounds per cubic yard of concrete.

• A. 300
• B. 310
• C. 320
• D. 290

Answer: (B)

Controlling the amount of free water in concrete is essential because it directly affects the water–cement ratio, which in turn governs strength, durability, and shrinkage. Free water is the portion of water in the mix that is not chemically bound or absorbed by aggregates; it’s the water that remains available to influence workability and bleeding. If free water is allowed to exceed the specified maximum, the water–cement ratio increases, leading to weaker concrete with higher permeability and more cracking potential.

In this context, there is a standard cap for free water per cubic yard, which sets the upper limit to prevent weakening the mix. Sticking to this limit keeps the mix within a workable yet strong range. Values below the cap still meet the requirement, while going above the cap would violate the specification and compromise strength and durability.