How does one go about repairing a badly worn and pitted concrete floor?
A good resurfacing job will restore the serviceability of the concrete floor. A 1-inch topping will be satisfactory if the topping is bonded to the old concrete surface. A minimum of a 2-inch, lightly reinforced topping is recommended when it is impractical to provide a good bond between the new and old surface. For a bonded topping, proper preparation of the base is essential. Roughen and clean the surface by removing all loose material and unsound concrete. Grease or oil should be removed by scrubbing with detergent. Sandblasting will remove paint and any skin coat of laitance. Wet the slab and keep it wet overnight. Before starting placing of the topping, remove any pools of water from the surface and permit drying for about 1 to 2 hours. A slush coat of cement and water of thick, paint-like consistency is broomed into the surface just ahead of the concreting operations. Good finishing and curing practices will result in a good wear-resistant topping. The mix should contain coarse aggregate--1/8- to 1/2-inch pea gravel or crushed stone. Recommended mix proportions by weight are 1 part cement, 1 part sand and 1 1/2 to 2 parts of coarse aggregate. For the unbonded surfaces, mix proportion, placing, finishing and curing procedures are the same. The 2-inch unbonded topping should be reinforced with mesh weighing 30 pounds per 100 square feet located in the midsection of the slab.