Concrete is often used to repair cracks in foundations and driveways. A concrete patch is good if the earth doesn't continue to move. If the foundation of the building continues to shift, or the driveway flexes, than it is only a matter of time until the crack reappears. However, if concrete is mixed with epoxy, the patch is able to flex with the movement of the foundation.
Prepare a bag of concrete according to the manufacturer's instructions. Do not add any extra water to the concrete however to make the concrete easier to manipulate.
Add sand to the mixture so that there is a 3-to-1 ratio of sand and concrete.
Mix 2 gallons of epoxy as directed by the manufacturer.
Combine the epoxy and the concrete mixture with 5 gallons of water. Stir the mixture well with a large stick to ensure that mixture is consistent throughout.