Effect of using greywacke aggregate on durability of concrete

[mattybhoy]

Can anyone shed some light or point me in the right direction for obtaining information on the use of greywacke aggregate on the long term durability of concrete. Also whether it will contribute or cause shrinkage cracking of the concrete both in both the short and long term.
Thanks
Mattybhoy

 

[Roadbridge]

I take that you or your company are planning to use such aggregate in your concrete?
Perhaps you should make contact with the technical rep of your local concrete supplier.

 

[mattybhoy]

thanks for the reply. Actually no I am not planning on using it. I have a very old mass concrete structure that has some wide cracks in a section 1m thick. Concrete cores show 27% cement content and use of greywacke aggregate which i feel is a likely contributing factor to the cracking.