Concrete Products

JUL 2019

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 July 2019 • 95 TECHNICAL TALK TOPCON MM GPS Patented technology combines advantages of laser and GPS working with the slipform machine's Topcon Millimeter GPS+ system to deliver fine tolerances in concrete paving. Lazer Zone, the Millimeter GPS paver system's machine control sensor is designed to com- pute the precise vertical information. There is no need for a moveable mast as the tech- nology is designed to determine elevation automatically. Even if the site has an eleva- tion variance of 10 meters (33 feet), there is no need to reposition the instrument or receivers with this technology. For sites with significant elevations or large areas, up to four LZ-T5 Lazer Zone transmitters can be linked to cover a larger area and elevation change of more than 130 feet. "Since we are free of stringlines, we like the efficiencies provided by the Millimeter GPS paver system," notes Kevin Gehring, owner/operator at Gehring Construction & Ready Mix Co., Columbus, Neb. "We're not needing to wait and pay for surveyors to be scheduled and pound hubs in ground. And we're no longer waiting and paying employ- ees to set stringline." Gehring believes he is also achieving better pavement alignment and rideability because he is able to use actual radius data for horizontal and ver- tical curves instead of short tangent string line sections. "We like the ease and flexibility the system provides us, since we're no longer married to a stringline with all the time and effort required to get the slipform paver set up," adds Scott Murchison, P.E., LEED AP, and chief engineer for RC Construction, Green- wood, Miss. "We recently paved a new runway at Joint Base Andrews in Prince George's County, Maryland, for Air Force One. The 3,000-ft. long by 250-ft. wide runway with two intersecting taxiways had a specified 7-inch per mile profilograph testing toler- ance. With our Topcon system, we achieved an incredible profilograph smoothness rating of less than 1 inch per mile." The Topcon Millimeter GPS paver system appears to help with paving accuracy—both in material usage and concrete lay down. "Our yields have been much better than expected," affirms Jacob Headrick, paving/3D manager, GLF Construction Corp., Miami, Fla. "We're dialed into the exact amount of mate- rial we need, which saves on material costs and eliminates rework. The accuracy with the Topcon Millimeter GPS system is phenomenal. We're achieving finished paved grade within a hundredth, and if you consider that a piece of aggregate can be bigger than that ... that's pretty spectacular." Headrick also cites savings and return on his technology investment as benefits: "With our first project, we saved enough to cover the cost of the Topcon system. On our second job, we saved enough on outside survey costs to purchase two Millimeter GPS systems if we wanted them." Certainly, technology is becoming inte- gral to professionals' desire for the smooth, uniform surface of freshly-paved concrete they all seek. According to the Federal High- way Administration, "Today's highway users expect a high-quality traveling experience on roads that are safe and well maintained with the least possible delay." The agency has several ongoing programs intended to ensure "that innovative technologies that can improve the safety and performance of the transportation system are deployed and implemented on the Nation's roadways." Clearly, one could expect that the tech- nologies being adopted by concrete paving companies are consistent with the stated mission of the FHWA and are directly con- tributing to the high-quality traveling experience highway users are expecting. — Topcon Positioning Systems, Livermore, Calif.; www.topconpositioning.com/na Jeff Winke is a business and construction writer based in Milwaukee, Wis. He can be reached through jeff_winke@yahoo.com.

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