Productivity Plus Quality Control by ProQuest


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									Compaction              I   Equipment

                 Productivity Plus Quality Control
Available technology helps smooth the path to compaction specs.
                                                                        By Kim Berndtson

T      echnology designed to help you achieve your
       soil and asphalt compaction objectives has
made tremendous headway in recent years, and is
                                                        higher degree of rebound and a higher reading,”
                                                        notes Dave Dennison, BOMAG Americas.
                                                           This information can be used by an intelligent
                                                                                                               provides information needed to make the correct
                                                                                                               choices to most efficiently build a good base.”

continuing to evolve at a relatively rapid pace. Its    compaction roller — a roller equipped with a docu-     Mapping out a
ultimate goal is to quantify density on the run —       mentation and feedback system — to automatically       clearer picture
i.e., identify density in real time under the roller.   adjust parameters such as vibration direction. The         GPS mapping systems are also becoming more
    While the technology isn’t quite there yet, there   roller operator can also use the stiffness data to     accepted on compactors. They can help “paint the
are several options currently available that can help   determine at what point to conduct traditional         picture” by showing an operator’s work pattern in
you quickly and effectively reach target densities.     sonic and nuclear density tests and spot core tests.   real time, plus can improve night-time operations
                                                           “Currently this new technology needs to be          where darkness may obscure the rolling pattern.
Monitoring soil stiffness                               used in conjunction with existing density tests,”          “GPS is another quality control tool,” says
    Soil compaction has essentially led the way with    says Dennison. “We’re not at a point where it can      Dennison. “It shows areas you’ve covered, and how
onboard compaction monitoring. As early as the          replace those tests. It’s another quality control      many times you’ve covered them. Plus, it shows you
1980s, Europeans were using these systems to help       tool contractors can use to reduce the cost of the     areas you may have missed so you can get higher
determine the effectiveness of the compaction pro-      job by, in one way, reducing the number of core        quality, more consistent compaction that should
cess. Similar systems began appearing in the U.S.       samples that may need to be taken.”                    result in more consistent density.”
earlier this decade.                                       “These systems provide operators with instant           Take Caterpillar’s AccuGrade Compaction GPS
    At the heart of onboard compaction monitors         feedback and information they wouldn’t otherwise       Mapping and Measurement System, which ties in
is an accelerometer that measures the response or       have,” adds Jon Sjoblad, Caterpillar. “The technol-    with the family of AccuGrade earthmoving tech-
rebound of the drum in respect to the frame. This       ogy allows operators to be more proactive, and it      nologies and grade control systems, including the
measurement allows a stiffness value to be dis-                                                                analysis software suite AccuGrade Office. It allows
played and correlated to density. (It’s important to                                                           you to track jobs and monitor productivity to
note that stiffness is not the same as density.) For                                                           ensure quality, as well as find hidden efficiencies on
example, loose, lightly compacted soil or asphalt                                                              the job.
will have a smaller response or rebound. “As you                                                                   “These systems can improve quality through pro-
make successive passes, you typically will get a                                                               cess control,” Sjoblad explains. “Previous to these
                                                                                                               systems, operators would rely more on their senses,
                                                                                                               then wait for verification. There’s downtime in this
                                                                                                               scenario. Also, only localized spots are tested, so you
                                                                                                               never really know if the whole job is compacted uni-
                                                                                                               formly. There can be areas where there is poor com-
                                                                                                               paction. But with this technology, you can see visual
                                                                                                               indications of compaction over every square foot.
                                                              Systems like the BOP (BOMAG Operating                “Uniformity is important in soil compaction,” he
                                                         Panel) provide data that can be used to verify        continues. “If you have localized areas that fail, you
                                                           and document the compaction process, and
                                                                                                               have to go back and fix them. And remediation is
                                                                        potentially reduce testing costs.
                                                                                                               a lot more expensive if it is done after pavement is
                                                                                                               laid, compared to fixing problems while the ground
                                                                                                               is open. An onboard compaction monitoring sy
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