What is the influence of angularity on aggregates?

Angularity in aggregates refers to the shape and edges of the aggregate particles. Angular aggregates, which have sharp edges and corners, increase the interlocking between the particles when they are compacted in a mixture. This interlocking enhances the mechanical strength of the concrete, as the angular particles tend to resist movement under stress, leading to a more stable and robust structure. The increased surface area of angular aggregates also allows for a better bond with the cement paste, which contributes to the overall strength of the concrete.

In contrast, rounded aggregates might provide less interlocking and lower shear strength, as their smooth surfaces allow them to shift more easily when force is applied. Therefore, the benefits of using angular aggregates in concrete mixtures directly relate to their ability to enhance strength and stability through effective interlocking and increased contact surface area.