What does "under-sanded" sand typically allow during the mixing process?

"Under-sanded" sand generally refers to sand that is lacking in fine particles necessary for optimal mixing in concrete applications. When sand is under-sanded, it can lead to a higher water-cement ratio because the larger particles do not fill the voids adequately, resulting in excessive bleeding. Bleeding occurs when water rises to the surface of the concrete mix, creating issues such as lower compressive strength and difficulty in achieving a smooth finish. This can also potentially lead to a harsh finish, making it challenging to work the surface properly.

The process of mixing concrete with under-sanded components often leads to complications, such as the need for additional finishing work to achieve desired aesthetic and structural qualities. Therefore, the adverse effects of using under-sanded sand during the mixing process include excessive bleeding and a harsher finish on the concrete, which can directly impact the overall quality and durability of the final product.