What is the typical maximum nominal aggregate size for structural concrete?

The typical maximum nominal aggregate size for structural concrete is 1 inch (25 mm). This size is widely accepted because it strikes a balance between achieving the required strength and workability in concrete mixtures. Aggregates that are too large can lead to difficulties in mixing, placing, and consolidating the concrete, which may result in voids and weak spots in the finished product.

Using a maximum nominal aggregate size of 1 inch helps ensure that the concrete can flow easily into forms, fill all spaces around reinforcing steel, and achieve a uniform texture. It is also consistent with industry standards, which recommend that for most structural applications, especially those involving reinforced concrete, the aggregate size be limited to no more than 1 inch to maintain the integrity of the structure.

Larger aggregate sizes would typically be used in specialized applications but can compromise the structural performance if not managed appropriately. Thus, the choice of 1 inch aligns with common practices and standards in construction.