Aggregates should have a resistance to different
chemicals. Imagine having a road built with salt. After heavy rains, the
entire road would collapse. Other rocks, especially clastic sedimentary
rocks are not resistant to water. Metamorphic rocks are sometimes too fractured
to be used. Igneous rocks and some chemical sedimentary rocks, like
chert, are suitable aggregates for use in the building and road
industries of today.
Mechanical properties refer to how the aggregate performs with
strength and stability. You do not want aggregates that will break down
when the first truck drives on a road.
Stones for the house and road