Davenport 360 is a five-story office building with 141 parking spaces on three levels below two stories of office space. Considered the “quintessential example of a modern Austin Hill Country corporate development,” the development is just off Loop 360 - Capital of Texas Highway in the hilly Westlake neighborhood of Texas’ capital city.
When construction on the 41,000 square feet of parking space was completed, an inspection noted drainage deficiencies on two of the structure’s three levels. To keep water from pooling in those areas, they had to be re-sloped to direct water toward the structure’s drains.
American Concrete Concepts Inc. (ACCI) was brought in to quickly remove and replace the concrete pavement. After saw cutting around the problem areas and removing the existing concrete, the crew shot blasted the substrate to International Concrete Repair Institute (ICRI) concrete surface profile (CSP) 3. They then applied TXP™ Fast Epoxy Primer to the profiled substrate and immediately broadcast sand over the wet surface.
Although designed to be used with Rapid Set® TRU® polishable floor toppings, the fast-setting primer also can be used to promote adhesion to other Rapid Set® products. In this case, that product was polymer-modified Mortar Mix Plus.
“I sometimes recommend the TXP™ and sand for a stronger bond,” says CTS Cement Manufacturing Construction Supply Representative Billy Rangel. “When the material is being applied directly over existing concrete, sometimes the user forgets to SSD (saturate surface dry), which could cause a problem. The TXP™ avoids that variable.”
The crews added five, 55-pound bags of Mortar Mix Plus to 20 quarts of water in a CS Unitech Hippo portable concrete mixer. To each batch they added two Rapid Set® concrete modifier additives: FLOW Control to increase fluidity and SET Control to extend working time beyond 15 to 20 minutes. Amounts varied depending on how hot the day was.
After pouring the mixed mortar on to the sanded surface, the crew manually screeded placements to set the proper elevation, troweled, and then broom-finished. They cured placements by keeping the surface wet for 1 hour.
Placements ranged from ½-inch to 3 inches to ensure proper drainage. A blend of Rapid Set® calcium sulfoaluminate (CSA) cement, advanced additives, and quality aggregates, Mortar Mix Plus is a structural concrete repair material that reaches 2000 psi compressive strength in 1.5 hours. It’s colored gray to better match most concrete surfaces and can be applied up to 6 inches thick.
Rangel recommended the product for its ease of use and because it contains corrosion inhibitor to protect any embedded steel to increase corrosion resistance. In addition to horizontal placements like a parking deck’s driving surface, Mortar Mix Plus is also commonly used to repair vertical surfaces like walls and columns.
