For the cracks, a two part epoxy caulk gun. The nozzles are replaceable, with a little spiral contraption inside them that mixes the two parts together inside the nozzle.
I worked on the construction of a meat processing plant years ago. In parts of the plant where it would be the coldest and the wettest, IIRC, they somehow spread out an even layer of marble chips. The marble chips came in 50 pound bags. The flooring guys had these wooden blocks strapped to their feet. There were nails driven through the blocks, so only the points of the nails made contact with the floor. I am pretty sure it was an epoxy they put down first...somehow sprinkled or broadcast the marble chips into or onto the still wet epoxy. And again IIRC, they applied another layer of epoxy, over the marble chips after the first had sufficiently cured.