Arizona Water Treatment Center Repair
Given twelve days to do the work in November 2003, Kauffman’s company began the project by power washing the splitter box at 3,500 psi (233 bar) to clean the concrete surface and remove loose material. The deteriorated areas were then abrasive blasted with copper slag. The contractor installed a new mat rebar system, securing it to concrete with drilled-in dowels or tying it to the existing rebar. The contractor then performed another power wash with an injection of a soluble salt treatment. Blowers were set up to mately two-inch (five-centimeter) thick layers, says speed drying, and six hours later, the contractor began apply-Kauffman. The concrete repair material was allowed to set ing the polymer concrete repair product by trowel. up for two hours before additional layers were applied. Working on one wall section at a time, the contractor The contractor built the walls of the concrete structure applied the polymer concrete repair product. Back to their original thicknesses, in some cases taking a 1/8-inch-thick (3 mm) area back to 10 in. (25 cm). The contractor performed adhesion tests on the concrete repair product, noting that the cementitious substrate failed before the polymer concrete repair product. The surface preparation, rebar installation, and rebuilding of the concrete took four days, says Kauffman.
Forced heat aided the cure of the concrete repair material, allowing the contractor to proceed with the lining application 12 hours later. Over two days, two coats of the chemical-resistant epoxy Novolac lining were applied by brush and roller to a total thickness between 30 and 35 mils (750 and 875 micrometers). The epoxy novolac was heat cured over the first night and then heat cured for 24 hours following the final application , says Kauffman. According to Kauffman, Pima County had an inspector on site during all working hours. The concrete splitter box rehabilitation was completed in less than 7 days, saving more money in “pump around facility” expenses than it cost to perform the work, says Kauffman. The contractor performed a follow-up inspection in March 2005, noting no signs of deterioration of the system.