What component is often eliminated from the aggregate mix in porous pavement?

In porous pavement, the aggregate mix is designed to allow water to permeate through the surface, promoting drainage and minimizing surface runoff. Sand is often eliminated from the mix because it tends to fill the voids between larger aggregate particles, reducing porosity. The absence of sand helps maintain the desired void spaces that are essential for effective water infiltration. This property is crucial for porous pavement to function as intended, ensuring that water can easily pass through and be absorbed by the underlying soil or drainage layer.

In contrast, larger aggregates such as gravel are typically retained for their structural support and drainage qualities. Clay and silt, being finer materials, also tend to compact and reduce permeability, which is why they are generally not desirable in the mix for porous pavement. Thus, eliminating sand helps achieve the goal of enhanced drainage and minimizing standing water, making it the correct choice.