>But crushed stone IMO is even better, it's not round and thus performs better in earthquakes.
Maybe if you manage to pump the concrete with a reasonable wear to the equipment, you mean.
Normally with crushed sand you need to increase cement quantities (because more water is needed) and need finer fillers like "flying ashes" and since you dont' want to have excessive resistance and thus excessive shrinkage, you need also other chemical additives.
And - just for the record - rounded aggregates tend to make stronger concrete, not the other way round, not because of the "surface", but because of the "shape", a concrete made of only spherical (in theory) aggregates has the less voids, and the more the actual shape of each aggregate tend to be similar to a sphere the less voids you find in the mix (that need to be filled by smaller fillers).
Of course this is "generally speaking", concrete is a product not much different from cooking, you need good ingredients, a good recipe, good equipment and a good cook to have a valid result.
Maybe if you manage to pump the concrete with a reasonable wear to the equipment, you mean.
Normally with crushed sand you need to increase cement quantities (because more water is needed) and need finer fillers like "flying ashes" and since you dont' want to have excessive resistance and thus excessive shrinkage, you need also other chemical additives.
And - just for the record - rounded aggregates tend to make stronger concrete, not the other way round, not because of the "surface", but because of the "shape", a concrete made of only spherical (in theory) aggregates has the less voids, and the more the actual shape of each aggregate tend to be similar to a sphere the less voids you find in the mix (that need to be filled by smaller fillers).
Of course this is "generally speaking", concrete is a product not much different from cooking, you need good ingredients, a good recipe, good equipment and a good cook to have a valid result.