Geologically these rocks are between basalt and granite and therefore there should not be any volume change issue with these rocks and these are used as base material for roads and buildings. However, the long term durability tests are recommended if these have not been used from these areas or exact composition is not known with impurities.

Thank you Dr. Chhangani. I noticed that the material used contains high amounts of SiO2 (silica). I am afraid some free silica may be there and may provoke alkali silicate reaction. In my opinion, mortar bar test or some other test must hace been conducted.

Sure, the effect is volumetric and dimension.

Regards