After collection, solid waste is usually dumped on what are called tipping floors at facilities such as transfer stations, balers, and incinerators. Vehicles tip the garbage onto the floor and bulldozers or front end loaders push or scrape the material into pits. All this dumping, pushing, and scraping subjects floors to extreme abrasive forces of impact and attrition. Conventional concrete floors lose the top inch of their surface in a few months under these harsh conditions. Only metallic toppings, installed at 1- to 2-inch thicknesses, can withstand the daily abuse tipping floors receive.
Cementitious metallic toppings are ready to use about 4 days after placement. Epoxy metallic toppings can be ready for use after 36 hours if placed at 70 degrees Fahrenheit or higher. Epoxy metallic toppings, though, cost about twice as much as cementitious metallic toppings at the same thickness; however, they can be applied at a minimum of one-half inch and have about 30 percent more relative abrasion resistance.
Before topping is placed, the base slab must have the correct surface texture or profile. The rough texture needed can be produced with a shotblaster or a grooving machine. Bonding agent choice depends on the age of the concrete slab. For new slabs, wait about a week after placement then use a latex-based bonding grout. For older slabs, use an epoxy adhesive.
