What is a common form of granular aggregate used in concrete?

The common form of granular aggregate used in concrete is sand and gravel. These materials are essential components that provide volume, stability, and strength to concrete mixes. Sand typically fills the voids between larger gravel particles, creating a well-graded aggregate mix that enhances workability and compaction of the concrete.

The combination of sand and gravel is favored because it achieves a good balance of size and texture, which contributes to the overall performance of the concrete. This mixture allows for improved durability, load-bearing capacity, and resistance to environmental conditions.

Other options like clay and quartz may have certain uses in construction, but they do not serve as primary granular aggregates in concrete. Clay, for instance, can retain water and is too plastic when wet, causing issues with concrete's performance. Limestone can serve as an aggregate, but it is often used in a crushed form rather than in its granular state. Quartz, while a valuable mineral and sometimes found in aggregates, is not a typical standalone granular aggregate for concrete mixes.