Which aggregate size is best for achieving a uniform exposed aggregate finish?

• A. Fine aggregate
• B. Coarse aggregate
• C. Medium aggregate
• D. Varied size aggregate

Answer: (C)

Achieving a uniform exposed aggregate finish is best accomplished with medium aggregate. This size offers a balanced consistency that allows the aggregate to be evenly distributed throughout the concrete mix. Medium aggregates are typically large enough to expose distinct particles without creating large voids or uneven surfaces.

Using a finer aggregate may result in a smooth surface that does not expose the stones appropriately, preventing the desired aesthetic finish. On the other hand, coarse aggregate might create larger gaps in the finish and can lead to a less uniform appearance as the larger pieces can cause an uneven distribution. A varied size aggregate can lead to challenges in achieving uniformity due to the different sizes interlocking and not yielding a consistently flat finish. Therefore, medium aggregates provide an ideal compromise for achieving a visually appealing and consistent exposed aggregate surface.