What is the maximum aggregate size relative to the vertical form?

What is the maximum aggregate size relative to the vertical form?

• A. 1/5 size of vertical form
• B. 1/3 size of vertical form
• C. 1/4 size of vertical form
• D. 1/6 size of vertical form

Answer: (A)

In vertical formwork, the largest aggregate must be small enough to flow through and fill the cavity evenly. Keeping the maximum aggregate size to about one-fifth of the vertical form’s dimension ensures rocks aren’t too large to pass through the opening, which helps concrete fill all areas, consolidate well with vibration, and avoid voids or honeycombing near the surface. If the aggregate were larger, it could bridge across the form and hinder proper filling and compaction; a smaller fraction is more forgiving but the common standard used here is one-fifth.

In vertical formwork, the largest aggregate must be small enough to flow through and fill the cavity evenly. Keeping the maximum aggregate size to about one-fifth of the vertical form’s dimension ensures rocks aren’t too large to pass through the opening, which helps concrete fill all areas, consolidate well with vibration, and avoid voids or honeycombing near the surface. If the aggregate were larger, it could bridge across the form and hinder proper filling and compaction; a smaller fraction is more forgiving but the common standard used here is one-fifth.