What type of aggregate is typically used for flatwork concrete?

The typical choice for aggregates used in flatwork concrete is coarse aggregate, such as gravel or crushed stone. This is because coarse aggregates provide the necessary bulk and strength to the concrete mix, which is essential for the durability and structural integrity of flatwork applications like driveways, pavements, and slabs. Coarse aggregates improve the load-carrying capacity of the concrete, offering stability and preventing deformation under standard usage conditions.

In flatwork applications, the size and gradation of the coarse aggregate are particularly important, as they help achieve a desirable balance between workability and strength. Properly graded coarse aggregates contribute to a reduction in the amount of cement required, resulting in a more economical mix without compromising the quality.

Fine aggregates, while essential for filling voids and improving workability, do not provide the same level of structural support as coarse aggregates. Synthetic and recycled aggregates can also be used in concrete mixes, but they are not as common for standard flatwork due to variations in performance and structural characteristics compared to traditional coarse aggregates.