Normally crushed materials don’t work well because the shape of the particles. Sand is smoothed by years of waves, crushed rock is jagged. This leads to issues with viscosity.
A direct example: railroad rocks. Rail tracks are laid on very well engineered rocks, that are designed to lock together under the weight of a train. They have a roughly 1x1x2 cross sectional ratio, specifically for that purpose. You don’t want that happening when you pour concrete.
Normally crushed materials don’t work well because the shape of the particles. Sand is smoothed by years of waves, crushed rock is jagged. This leads to issues with viscosity.
A direct example: railroad rocks. Rail tracks are laid on very well engineered rocks, that are designed to lock together under the weight of a train. They have a roughly 1x1x2 cross sectional ratio, specifically for that purpose. You don’t want that happening when you pour concrete.