Question: How do you epoxy inject cracks in floor slabs on grade when you do not have access to the bottom of the slab? What keeps the product from running out the bottom and all over the place?
Answer: We make these type of repairs all the time. The first thing to do is dump the epoxy. It is too thick, too brittle, and takes too long to set. Fast setting materials like 10 Minute Concrete Mender allow you to control set points deep in the crack and prevent material seepage.
Roadware 10 Minute Concrete Mender™ has an ultra low viscosity of 8cps and will gravity inject into the smallest of cracks. We make the repair in stages adding fine silica sand into the crack as necessary to prevent the material from running out the bottom. The product can be injected with needle tip mixers as small as 18 gauge. With careful technique and experience you can make structural repair that will restore aggregate interlock and restore the slab.
Start out by adding a small amount Concrete Mender to the prepared crack and noting where material in running beyond the slab. Add a light dusting of silica sand or fine quartz to the crack and some more Concrete Mender. The Concrete Mender will combined with the particles of sand to form a quick setting, "mud" at the bottom of the crack. Repeat as necessary and repair the full depth of the slab.
This will be a structural repair with no ports, no pumps, and almost no down time.