understanding metamorphic rocks 1

[techmaximus]

Metamorphic rocks are rocks that have been changed either in texture or in mineral composition by any of the following: heat, pressure, directed pressure (stress), shear, or chemically active solutions. Changes that take place in weathering and lithification (change from loose sediments into solid rock) fit the definition but are not considered metamorphic.

My question is this, in reference to aggregate for concrete metamorphic implies what or is important why?

Senior Engineering Tech
CMT/Geotech

 

[iandig]

The geological/petrographic description of a rock is important because based on this predictions can be made as to the 'characteristics' of the rock, along with the physical, mechanical and chemical testing required for approval.
There is a lot of information out there which allows the comparison between the geological description and the prediction of material proerties. Also, there are rock types out their which have been proved to be unsuitable for use in concrete.