Type 1 subbase density – Materials Man
So in my humble option you should use 2.1 / 2.2 t/M3 for aggregate that has a relative density of 2.7 / 2.8 t /M3. Limestone will be less in proportion to it's relative density as will granite, and some igneous rocks will be more, such as from Hillhouse Quarries in Ayrshire whose relative density from memory is 2.9 t/M3. the lack of facts is ...