Urethane Fast Cure Crack Filler Kit is a two-part, high penetration, fast setting, hybrid polyurea for repairing and rebuilding damaged concrete. The product is a 1:1 ratio, an easy-to-mix system that is 98 % solids, and VOC compliant. This can be used to set anchor bolts, repair damaged control joints, fill spalling, and rebuild vertical curbing and steps. Sand or gravel can be added to extend the volume of the material and act as fillers for repairing large spalls, holes, and cracks.