Well, the heat would have to travel through the adhesive before heating the concrete or any water in that concrete. The adhesive on the concrete would be molten and easy to scrape off with a paint scraper long before the damp concrete under it ever got warm enough to make any difference.
I'm thinking that if a person simply propped up a heat gun on a book or something to blow hot air over the adhesive, they could expose a large area of the underlying concrete with a paint scraper fairly quickly. That's cuz the hot air from the heat gun would travel quite far over the surface of the floor. You don't need to scrape all the adhesive off; you just need to remove enough of it to allow the underlying concrete to absorb water.
In my building, I didn't have any problem getting the concrete in my locker rooms wet, so maybe it won't even be necessary to do any scraping with a paint scraper. But, in my case I could see that the adhesive was troweled on sparsely. If you pull up the flooring and see an impermeable layer of black asphaltic adhesive on the concrete, I'd try using a heat gun and paint scraper first as I expect that would work best.
Just make sure that the concrete is damp before using any solvent to dissolve the adhesive. Maybe scrape off areas where there still was residual adhesive and find out if the concrete under that residual adhesive is white (like dry concrete) or a medium grey (like damp concrete). Concrete is pretty dense, so it'll take time for moisture to migrate laterally through it.
Last edited by Nestor_Kelebay; 06-08-2009 at 09:38 PM.