Which factor does NOT directly influence the specific gravity of a coarse aggregate?

• A. Shape of aggregate particles
• B. Type of parent material
• C. Presence of surface moisture
• D. Aggregate color

Answer: (D)

The specific gravity of a coarse aggregate is primarily determined by its physical characteristics and the materials from which it is derived. The shape of aggregate particles affects how they pack together and consequently influences their density. The type of parent material plays a crucial role as different materials have varying inherent densities, affecting the overall specific gravity. Additionally, the presence of surface moisture can influence the measurement of specific gravity, especially if the aggregates are saturated, as it can add weight and create variations in density.

On the other hand, aggregate color does not have a direct impact on its specific gravity. Color is a superficial trait that doesn't influence the internal properties or the density of the material itself. Therefore, while it may provide some qualitative information about the material (such as mineral composition), it does not play a role in calculating or determining specific gravity values.