What does consolidation refer to in concrete mixing?

Consolidation in concrete mixing specifically refers to the even distribution of all mix ingredients throughout the concrete to ensure a homogeneous and uniform mixture. This process is crucial because it helps eliminate voids and air pockets within the mix, which can negatively impact the strength and durability of the final concrete product. Proper consolidation ensures that all components—such as cement, aggregates, and water—are uniformly combined, leading to optimal performance in structural applications.

The other options describe different aspects of concrete. For instance, removing air from cured concrete is important for achieving better density but relates more to curing techniques and quality control than to the mixing process itself. The increase of volume in wet concrete doesn't accurately describe a process within mixing, as volume stability is a critical consideration during formulation and application, not a direct action in mixing. Lastly, the hardening of concrete is a different phase that occurs after mixing, involving hydration and setting, which solidifies the mixed components into a solid mass but is not related to the mixing process of consolidating materials uniformly.