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Revitalizing Dallas work on the concrete substrate. From start to fnish, they worked on the park deck for about 18 months, completing approximately 10,000–15,000 square feet (929–1,394 m²) per week. According to Wharton, at any given time, the crew had 50,000–90,000-square-foot (4,645–8,361 m2) sections within which to work. "All of the concrete was new construction, with some areas pre-cast and others cast-in-place. Te hot-applied coating has to be applied to cured concrete, and depending on the weather, this process can take anywhere from 14 to 28 days. Te pre-cast pieces were all caulked with Henry #925 BES Sealant before we began applying the hot fuid-applied system," stated Wharton. Tis aspect of the project was extremely important as the freeway in the tunnel below the park deck was open throughout the duration of the job. Tere was zero tolerance for anything that could potentially fall through the cracks onto cars below, including any of the 400° F (204° C) waterproofng fuid. Once all the joints were sealed, the crew used 3,000-psi (21 MPa) power washers to clean the concrete substrate and remove any dirt or debris. At this point, all trench beams, joints, transitions, and penetration points were detailed with Henry Neofash elastomeric membrane that was embedded in Henry 790-11 hot fuid-applied asphalt. "Tis fashing membrane is a fexible rubber sheet that, when embedded in the 790-11, creates a continuous surface," said Wharton. With the elastomeric membrane in place, the crew then spray-applied Henry 910 asphaltic primer to the entire section of concrete. Te primer not only prepares the surface for the application of the hot fuid-applied waterproofng coating, but it also acts as a vapor barrier. According to Wharton, as long as the primer is coated within a week, if it rains, the moisture can simply be wiped of. In other words, water does not soak into the primer layer. Hot, Hot, Hot Once the primer was applied to the substrate, it was time for the crew to apply the hot waterproofng coating. "Henry 790-11 is rubberized waterproofng asphalt that is shipped to the job site in large bricks. Onsite, the bricks are placed in temperature-regulated agitating kettles. Te kettles are constantly moving, similar to a cement mixer. Te agitation, along with the high temperature of the kettle, keeps the rubberized waterproofng asphalt in liquid form," explained Heather Paschal of Henry Company. Te 400° F (204° C) material was dispensed from the 300-gallon (1,136 L) kettle into buckets and very carefully carted to the application area. Te extremely hot material was then dumped out and squeegeed onto the horizontal surfaces. "We had three to four 2 14 Wishes for a healthy In terms and prosperous new year! of chemistry, polyurethane is the result of CHLOR between an a reaction RID International isocyanate and a hydroxyl terminated polyol group. chlor-rid.com Write in Reader Inquiry #142 88 JANUARY 2014 COATINGSPROMAG.COM