Which type of aggregate generally requires more water and cement to be workable?

Angular aggregate particles are typically more challenging to make workable compared to rounded aggregates. This is primarily due to their shape and texture. Angular aggregates have a rough surface with sharp edges, which creates more friction when mixed with water and other ingredients. This increased friction means that more water and cement are needed to achieve the desired workability in the concrete mix.

The angular shape also means that these aggregates interlock more than rounded particles during mixing, leading to higher resistance to flow and a denser packing. As a result, to ensure that the concrete can be placed and finished properly, the amount of water and cement must be increased to achieve sufficient lubrication and consistency in the mix.

In contrast, rounded aggregates roll more freely and require less water and cement for adequate workability because their smooth surface allows them to move past each other more easily, reducing resistance within the mix.