Concrete Products

AUG 2014

Concrete Products covers the issues that attract producers of ready mixed and manufactured concrete focusing on equipment and material technology, market development and management topics.

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www.concreteproducts.com August 2014 • 29 FEATURE RCC PAVEMENT RCC with rougher surface prone to superfcial crazing, but density characteristics assuring long service life in the face of vehicle loads and Upper Midwest freeze-thaw cycles. Catholic Cemeteries and Arlington Heights, Ill., civil engineer Ament Design approved a Prairie and J&R-proposed demon- stration for the second placement: A more prominent shop area with power-troweled, broom-fnished pavement, its top 1/4 in. hardened and densifed with RCC Surface Pro. Finish quality compelled the decision to maintain the new specifcation for two sub- sequent pavement sections under the Prairie and J&R contract, totaling 54,000 sq. ft. COTTON CURE Catholic Cemeteries staff will monitor Mary- hill maintenance shop slab performance with an eye toward broader use of troweled RCC throughout northern Illinois properties, which encompass 100-plus miles of lighter duty, primarily asphalt roads. The organiza- tion has enlisted Prairie Material and J&R to deliver broom-finished RCC for a section of road at Resurrection Cemetery in Justice, Ill. The Catholic Cemeteries' contracts join an RCC pavement roster Prairie has built since 2009, with this year's volume reaching 40,000-plus yd. The producer has promoted RCC for a) heavy industrial pavements, where surface aesthetics or smoothness are second- ary to load-bearing; and, b) municipal proj- ects, where agencies typically call for an as- phalt wear course over a 5 or 6 in. RCC base. J&R 1 st in Asphalt teamed with Prairie Material from the outset to convert the Maryhill maintenance shop pavement. "The contractor has embraced the RCC concept and aggressively worked with us to move several of clients from asphalt to RCC," notes Theron Tobolski. In advance of Maryhill slab troweling and foating, he pointed J&R crews to a re- cently established RCC pavement practice: Placement of water-soaked cotton blankets along lift or layer edges considered fresh joints. Standard in Illinois Department of Transportation concrete bridge deck curing specifcations, the blankets maintain mois- ture levels critical to proper RCC base and top lift conditions. By eliminating edge drying, contractors gain effciency in longer paving trains and drum roller passes. "One of the hardest things in RCC mix and asphalt paving is to blend fresh joints in a timely manner so they don't ravel. I recom- mended a contractor on a previous RCC proj- ect use wet burlap on the fresh joints to keep them from drying out," Tobolski recalls. "The contractor agreed with the concept but used cotton blankets. The process gave crews the ability to pave longer lanes and noticeably raised fresh joint density." Prairie Material supplied 1,000 yd. of roller compacted concrete mixes for the Maryhill Cem- etery maintenance shop pavement from its Des Plaines, Ill., plant. With temperatures into the 80s, contractor J&R 1 st in Asphalt used tarps for inbound dump trucks to minimize mois- ture loss; to keep beds cool, it instructed drivers to unroll tarps for the eight-mile return to the plant. Taking a cue from a contractor on another Prairie Material RCC pavement job, the J&R crew placed saturated cotton curing blankets along fresh joints, ensuring proper density at a critical condition. Conventional RCC pavement (vibratory and static roller drum pass only) was placed at the back of the maintenance facility. Results from the frst troweled/RCC Surface Pro placement (above, foreground) drove subsequent specifcations for more prominent, higher traffc areas. Continued on page 30 PHOTOS: Concrete Products

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