ACI Aggregate Base Testing Technician Practice Test 2026 – Complete Exam Prep

Finer, angular aggregates are best for dense packing due to their shape and size characteristics. Angular aggregates have more surface area contact points and interlock well with one another, creating a tighter, more compact mass. This interlocking ability allows for more effective load transfer and stability within the aggregate structure. Additionally, the finer grading fills voids between coarser aggregates, minimizing the spaces and allowing for a denser arrangement.

In contrast, while round aggregates can roll against each other, they do not interlock as effectively, leading to less dense packing. Coarse aggregates, whether round or angular, typically provide less surface area for packing and are more suited for applications where larger aggregate is needed, such as base layers in pavement structures. Thus, finer, angular aggregates facilitate the densest packing configuration for aggregate materials.