Better Roads Digital Magazine
Issue link: https://read.dmtmag.com/i/85926
roadway based on these spot tests. Unfortunately, densi- ties measured in those spots may not be representative of the entire roadway section. A Closer Look Todd Mansell, a training consultant for Caterpillar Global Paving Products, defi nes an IC roller as one that has: Of roller manufacturers offering machines in the systems that use an accelerometer to measure asphalt something that can measure density, but no system can frequency response of the drum changes – the wave that measures the response becomes more irregular. In theory, one can correlate stiffness values from IC systems to laboratory fi nd- ings and come up with as- quite that simple, because accelerometers have their celerometers are responding to ground conditions 3 to 5 Mansell. IC systems is the variety of ways they analyze the accel- IC can provide a better method of quality control be- cause real-time information is being relayed to the roller operator related to pass count, the in-place material stiff- ness, and mat temperature. Once laid down, asphalt has an optimum window of temperature during which compac- it stiffens and will not compact as easily. Temperature sen- sors on IC rollers can indicate mat temperature and feed or tear out and replace the cold asphalt. IC systems can provide a color-coded map showing stiffness values, mat surface temperatures and pass counts of the entire roadway. IC provides 100 percent coverage erly compacted material. What They Offer has a CCV, or compaction control value, and it has no the core density to the roller-measured values, but most As the density increases, the frequency response of the drum changes – the wave that measures the response becomes more irregular. surface, based on stiffness readings that the machine cess called vectoring, which involves changing the angle the drum will direct energy at a straight vertical angle. energy at a more horizontal angle until the vector goes totally horizontal when the surface reaches optimum compaction. his system does not measure density, but measures as- help you correlate stiffness to density at a given tempera- Better Roads July 2012 9