Conquer Earthmoving Essentials 2026: NCCER 22201 Test Prep Adventure!

Aggregate is the material described here. It refers to manufactured or natural rock or sand that is processed to a specific size range and used as a base under foundations and for subgrade work. Using aggregate with the right size distribution improves compaction, strength, and drainage, creating a stable foundation. Gravel and sand are types of aggregate, but the term aggregate encompasses the whole range of sized materials used for these applications, while fill is simply material used to raise the ground level and doesn’t imply a defined particle size for foundation purposes.