GSSI and Hamm Roll Out Onboard Asphalt Density Scanning

Geophysical Survey Systems, Inc. (GSSI) has reached a long-term agreement with Hamm AG to integrate a key new sensor to their digital compaction assistant Smart Compact for tandem rollers. They now present RealTime Density Scan for Asphalt.

The agreement enables a new era in asphalt compaction technology for real-time quality control (QC) and for quality assurance (QA) on asphalt paving jobs. Hamm and GSSI have worked closely to create the RealTime Density Scan, a high-speed, highly accurate sensor that can handle the harsh paving conditions of vibration, dirt, moisture and temperature under a roller. Roller operators will have the compaction control they need to ensure uniform densities and to create longer lasting roads using less energy, according to the companies. GSSI President Chris Green said, “Given the trajectory

of density profiling systems in the industry, the natural next step in the PaveScan ecosystem was to integrate this technology into asphalt rollers. This agreement with Hamm combines the long-standing strengths of each company to provide customers with a truly innovative solution on a large scale. We couldn’t be more excited about working with Hamm and the future of DPS.”

GSSI has been working on the core ground penetrating radar (GPR) sensors and algorithms required to deliver highly accurate results across a large range of compaction scenarios for a number of years. GSSI CTO Dr. David Cist explained, “This is a hard problem to solve at the accuracies required.”

Dr. Cist continued, “DOTs pay bonuses for good density because their research shows that each 1% change in compaction can extend or shorten road life by 10% or more. Since water is the enemy of all roads, getting good densities over the entire job is key to longer road life, since it seals out salt and water. However, the problem has always been that paving contractors have meager feedback for rolling asphalt to the right density. Knowing surface temperature, roller pass count, and stiffness are all great, but they can never be combined to give the density values contractors need at the accuracy DOTs pay for. Gauges and cores provide only spot density values, typically too late and too sparse to assure longevity.”

PaveScan technology has been used by domestic and international DOT’s for many years. The first few years of this work was primarily focused on Quality Assurance—making sure the road meets specifications after the job is done. The next step was to work with DOT’s and contractors around the world to design a system that allows for real-time Process Control, which enables contractors to fix problems during the job, rather than just pay for them after the job is over. This is a win-win for everyone involved. Extensive testing, across a variety of conditions, consistently shows that PaveScan products in the plant and on the mat provide actionable density information at all stages of the process.

Check out the article “NDDOT Trials New Technologies on Hwy 14” in the March/April issue to see this technology in action.

For more information, visit the GSSI website.