While Shelly Company is now sold on the value of using profilers as an in-process tool, it wasn't always. Shively admits the main reason for initially using profilographs years ago was that it was required by the Ohio Department of Transportation (ODOT). But the company quickly saw the tool's advantages, and the use of profilers has now expanded to non-ODOT projects such as commercial, city and county paving.
"The use of profilers makes us more aware of the product we are supplying our customer and more conscientious of what influences smoothness," Shively says. He is quick to point out that Shelly Company has always delivered a quality product, but by incorporating profilers into the company's quality control routine, the product is now even better. It helps them achieve bonus level work, and they also have a database of numbers to submit to associations for award consideration in Ohio and on the national level.
Evolution of technology
Nearly a decade ago, paving contractors had only one choice for obtaining the profile of a surface, the profilograph. While these machines would give contractors the necessary profile numbers, they were time consuming to use.
"The profilograph was the tool of the trade, but since its speed ranged from 1.5 to 3 mph, it was impractical for in-process monitoring of smoothness," Klatt mentions. As a result, most paving contractors would use the profilograph to measure the final surface numbers.
The introduction of John Deere Gator-mounted lightweight profilers, like the Model 6200 Profiler nearly seven years ago, gave paving contractors a more flexible tool that could be used in a variety ways.
"Our Lightweight Profiler allows contractors to measure the pavement's smoothness at speeds ranging from 8 to 15 mph, more than five times faster than profilographs," says Dustin Reid, product manager for Ames Engineering.
This results in shorter lane closure times for profiling and allows contractors to begin to incorporate the profiler as an in-process tool for their paving operations, just like the Shelly Company. "It also helps to enhance safety, since the crew leaves the work zone quicker," mentions Klatt.
The concrete industry and concrete paving contractors were quick to adopt the technology. It gave them an in-process diagnostic tool to help enhance the pavement's smoothness.
"Its relative light weight enables contractors to get on the slab the next day to collect profile data," Reid explains. "This data is critical to help determine and diagnose problems with string line setup, paver controls or concrete placement in front of the paver."
A few years after the introduction of Lightweight Profilers, the industry began to see the first high speed profilers like the Ames 8200 models owned by the Shelly Company.
Supplied in a "kit" form, these profilers do not require a specialty vehicle, as this new generation unit mounts quickly to any two-inch hitch receiver in the contractor's own vehicle fleet.
Higher speeds enable a profile to be efficiently taken on every lift and at multiple sites. Shelly Company uses its three profilers to measure smoothness for 20 paving crews.
"The higher speeds allow us to cover more paving crews in a shorter period of time," Shively says.
Variety of configurations
Over the years, the technology of profilers has advanced to improve their accuracy. "The information captured by today's profilers is much more accurate than that from profilographs," Klatt says.
The data gathered offers a true elevation profile that plots a California profilograph or rolling straightedge; and it calculates the International Roughness Index (IRI), a Profile Index (PI), Half-car Roughness Index (HRI), Ride Quality Index (RQI), and Ride Number (RN).
According to Reid, more states are going to IRI, since it better reflects what the public feels when driving on a road. "It's based on an algorithm that more heavily rates the short wavelengths like bumps at an expansion joint, but it still counts the longer wavelengths like rolling undulations," he says. "It's more of a true ride reflection."
To help obtain a more accurate IRI number prediction, Ames Engineering developed dual sensor profiler models, which make up the majority of the company's sales. These dual sensor models profile both the left and right wheel tracks as compared to only one wheel track measured with a single sensor system. This results in a more accurate smoothness reading.