How does aggregate size influence the strength of concrete?

The influence of aggregate size on the strength of concrete is significant and multifaceted. In considering the correct option, it is important to understand how larger aggregates function in a concrete mix.

Larger aggregates do indeed have the potential to hinder workability, which refers to how easily the concrete can be mixed, placed, and finished. This is primarily because larger aggregates create a more rigid particle structure that may not flow as effectively through the mix, especially in intricate forms or when detailed finishing is required.

However, the presence of larger aggregates contributes positively to the structural stability of the concrete once it has cured. The larger particles provide a better interlock and load distribution, enhancing the overall strength of the final product. They also reduce the total surface area that needs to be bonded with cement paste, leading to reduced shrinkage and cracking, which contributes to the durability of the concrete.

In summary, larger aggregates balance the trade-off between workability and structural stability, improving the strength and stability of the concrete while potentially complicating the mixing and placing process. Understanding this balance is crucial for concrete finishers to optimize their mixes for specific applications.