Pavement engineering firm The Transtec Group led Australia’s first Intelligent Compaction (IC) workshop in Brisbane to share what agencies in the US have learned and experienced in the past 15 years of IC implementation.

IC is a roller-based technology that measures roller passes, compaction temperatures, and stiffness of compacted materials in real-time. It allows for the real-time detection of paving and compaction issues so paving crews can adjust the operation to improve the final pavement quality. Using IC improves construction quality control (QC) and efficiency to make pavements last longer and to reduce maintenance costs.

The workshop, held on May 8, brought together Australian agencies, research groups, contractors, and vendors. It was organized by the Australian Geomechanics Society and co-sponsored by Monash University, the Australian Road Research Board (ARRB), Queensland University of Technology (QUT), FSG Geotechnics & Foundations, Insitu Test, and the Australian Asphalt Pavement Association (AAPA). Topics covered included IC basics/theory/models, how IC can be implemented, lessons-learned from implementation in the US and China, a demonstration of Veta software, IC case studies from Australia, and a vibrant panel discussion.

Those in the panel discussion included an executive of AAPA, which plans to support road agency and industry members in the introduction of IC and address any barriers.

“The Australian Asphalt Pavement Association and its members are interested in IC as part of our industry’s commitment to continual improvement,” said Dr. Erik Denneman, AAPA Director of Technology and Leadership. “We expect that IC will lead to increased uniformity of compaction.”

Peter Evans, the Deputy Chief Engineer with the Department of Transport and Main Roads (TMR) of Queensland, was also member of the panel discussion.

“It was interesting to see how well-developed IC technology is now and its increasing use in the US,” said Evans. “I look forward to working with the industry to introduce this into TMR.”

Dr. George Chang, Director of Research at The Transtec Group, led the workshop.

“The main takeaway from Transtec’s IC workshops is for agencies, groups, and companies to fully understand IC’s benefits and see how it can be a great quality control tool,” said Dr. Chang.

The Transtec Group recently provided complete consulting support to the Missouri Department of Transportation (MoDOT) during a year-long IC and infrared scanning (IR) demonstration project. Because of the success of the project, MoDOT has committed to fully implementing IC by 2021.

Other agencies or companies interested in IC or IR—also known as paver-mounted thermal profiling (PMTP)—can get started with the Intelligent Construction Technical Support Center. Services offered include online HelpDesk support for Veta software, training workshops, field project support, and complete support packages.

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Adequate and uniform compaction of road materials, such as soils, aggregate bases, and asphalt pavement materials, is one of the most important requirements in roadway construction. It is indispensable to strive for high quality of compaction to ensure long-lasting performance. Intelligent Compaction (IC), which uses modern vibratory rollers equipped with an integrated measurement system, an onboard computer reporting system, Global Positioning System (GPS) based mapping, and optional feedback control, helps improve compaction quality control.

“Intelligent Compaction provides crews with continuous compaction control with real-time monitoring,” said Dr. George Chang, Director of Research at The Transtec Group. “IC can help the roller operator better control and achieve the coverage for compaction, which is very difficult to do without guidance.”

Now that construction season is well underway in the United States, the Federal Highway Administration (FHWA) and pavement engineering firm The Transtec Group published two intelligent compaction technical briefs to help construction teams and organizations effectively and efficiently implement IC.

Specification for Intelligent Compaction

The Specification for Intelligent Compaction Technical Brief (FHWA-HIF-17-037) provides a review of national and state IC specifications and recommendations for future enhancements. The FHWA and AASHTO have developed national IC guide specifications and an increasing number of state agencies have also developed their own IC specifications. There is a lot of variance, however, among the contents of state IC specifications.

“Without requiring IC in construction specifications, it is very difficult to make IC widespread,” said Dr. Chang. “The goal of the tech brief is to make complicated technical content more palatable to the public so they can digest the material in a short-form publication.”

Common elements of IC specifications include IC system requirements, a quality control plan, training, field operation requirements, data requirements and submission, and measures and payment. This tech brief provides guidance for state DOTs to customize those elements into their specification.

Color-Coded IC Maps

The Color-Coded IC Maps Technical Brief (FHWA-HIF-17-036) outlines guidelines and recommendations for color-coded maps using IC and paver-mounted thermal profiler (PMTP) data. These maps include items such as roller passes, asphalt surface temperatures, and stiffness values.

IC and PMTP systems have been gaining popularity across the US over the past decade to improve compaction quality and detect temperature segregation behind pavers. On IC and PMTP systems, color-coded maps from their onboard displays are used extensively for monitoring and visual inspection of collected field data and machine operation.

“Visual inspection in the field is one of the very first steps for quality and acceptance of construction, such as meeting required roller passes and coverage and minimum asphalt temperatures” said Dr. Chang. “Using a consistent color palette will make inspections consistent and the process robust.”

Veta Software

IC and PMTP systems gather a tremendous amount of complex geospatial data that poses challenges for data management, analysis, and reporting. These issues have become the main hurdles during implementation. To address the above issues, the Minnesota Department of Transportation, FHWA, and the Transportation Pooled Fund Study, TPF-5(334) have funded development of the Veta software tool for IC and PMTP data viewing and analysis.

Veta is a map-based software tool for viewing and analyzing geospatial data. Currently, Veta can import data from various IC machines and PMTP scanners to perform editing, filtering, spot test correlation, and statistical analysis as a post-processing tool.

One of the salient features of Veta is viewing IC and PMTP data as color-coded maps on top of geographical road or aerial maps to facilitate quantitative interpretation. Key examples are for evaluating consistency of rolling patterns and for identifying cold blobs or streaks of asphalt temperature segregation. Veta allows users to select any specific passes to be viewed, including the last pass or final coverage.

Veta is required in FHWA and AASHTO PP80-17 specifications, and is increasingly adopted by state highway agencies.

The Transtec Group developed Veta with support from the FHWA. Veta is free to download. Currently, the Transportation Pooled Fund (TPF) study, “TPF-5(334) Enhancement to the Intelligent Construction Data Management System (Veta) and Implementation” is leading the effort for enhancing and maintaining Veta to facilitate the national IC/PMTP implementation.