What influence does the size and angularity of fine aggregates have on their packing density?

The influence of the size and angularity of fine aggregates on their packing density is significant, particularly regarding how angular aggregates enhance the interlocking mechanism. When aggregates are angular, they have more edges and faces that can interlock with one another, creating a denser arrangement. This interlocking ability allows for better stability and resistance to movement under load, which improves overall packing density.

In contrast to angular aggregates, round aggregates tend to have smoother surfaces and less opportunity for interlocking, which can lead to a lower packing density. Additionally, the size of the aggregates plays a role; smaller aggregates can fill the voids between larger ones, but if they are not angular, they will not provide the same level of interlocking that is crucial for maximizing packing density.

While it is true that various shapes and sizes of aggregates will result in different packing densities, the specific dynamic created by angularity and size directly contributes to how well the aggregates can be compacted into a dense configuration. This makes the concept of angular aggregates improving interlocking and thus improving packing density particularly relevant in the context of aggregate testing and evaluation.