The problem of repairing spalled and cracked areas of concrete structures has existed since the advent of cementitious materials. The notable lack of success associated with bonding new concrete to old by simple means is familiar to all who have worked with concrete materials. Many products have appeared on the market from time to time and proved effective in varying degrees. None, however, could ever be considered to bring about restoration of concrete- at least as permanent as the original. Now such engineering materials are available, and the fact is buttressed by a large amount of realistic test data. All of these products are based on a relatively new liquid resin- called Epoxy- which, upon the addition of a hardener, sets up at normal temperatures to a remarkably tough plastic. The addition of another resin results in an alloy- a plastic alloy with resultant improvement fully as surprising as its metallic counterparts such as iron-steel or copper-brass. Other "alloying" ingredients are being, tested as partial replacements in order to effect cost reductions as well as even greater improvements in functional properties. A catalyst or hardener includes in the Epoxy Alloys which chemically causes the liquid alloy to set up to a hard, tough solid. The function of the hardener may be compared somewhat to that of calcium chloride in concrete mixes, where the effect is to increase the initial set and ultimate cure time of concrete. The uses of Epoxy Alloys already over a large area, and the number is increasing rapidly. They are being used with good success in the repair and restoration of all types of building, highways, and roads, walks, underpasses and bridges, basements , swimming pools, irrigation and sewer systems, dams, silos and grain elevators. In these applications they are bonded to concrete, brick, tile, glass, plaster, stucco, wood and stone, as well as to some asphalts and plastics, and their function is to correct such faults as spalls, honeycombs, cracks, cleavages, porosity, and roughness.