On Saturday, February 9, 2019 at 2:45:42 PM UTC-5, wrote:
On Sunday, January 27, 2019 at 11:02:20 AM UTC-8, Michael Black wrote:
... off topic question ...

His topic is removal of grout; so the question and replies
are on topic. The topic is out of the scope of this group
of course.

It is on topic, because sometimes metallic and non-metallic electrical conduit runs through fill encased in concrete.