ARRB: Good vibrations

Dr. Lee presented at ARRB’s Smart Pavements Now Masterclass.

Australian Road Research Board Principal Professional Jeffrey Lee talks to Roads & Infrastructure about the efficiency potential of intelligent compaction.

Artificial intelligence is affecting almost every area of the civil construction and transport industry. Whether it’s building information modelling, smart highways or connected trucks, automation is inescapable.

An associated technology of the machine learning movement is intelligent compaction (IC), despite the fact that it was invented decades ago.

According to Dr. Jeffrey Lee, Australian Road Research Board (ARRB) Principal Professional, IC was developed 40 years ago in Europe, and has been widely used in the United States for 15 years.

“A few contractors have been experimenting with IC technology in Australia, but it hasn’t gone mainstream yet,” he says.

IC refers to the compaction of road materials using a vibrating roller equipped with an integrated measurement system and survey-grade precision GPS unit. When used specifically for asphalt compaction, infrared temperature sensors are also enabled.

Dr. Lee, who serves as project leader for the National Asset Centre of Excellence Implementation of Intelligent Compaction Project, says he wants to see wider Australian uptake of the technology.

“IC is not blue sky research. It is completely accessible now,” he says.

“My main objective is to get industry, asset managers and road authorities to buy in and use it.”

Vibratory rollers operate on the principal of dynamic force created by the weight of the roller and rotating masses in the roller drum. The vibratory rollers consolidate the soil and asphalt layer after each subsequent roller pass, and if done effectively, enhance the engineering properties and longevity of the civil engineering material.

“Efficient compaction requires optimum density to be achieved as quickly as possible, using the minimum number of passes,” Dr. Lee says.

“Current compaction procedures often result in non-uniform material densities, which is a major issue for early pavement failure.”

Dr. Lee says IC circumvents this issue by tracking every movement the roller makes and constantly reading the in-situ stiffness levels.

“Constantly tracking in-situ stiffness leads to improved construction quality control, efficiency, uniformity and as a result, a reduction in construction and maintenance costs,” he adds.

Dr. Lee presented the benefits of IC on day one of ARRB’s Smart Pavements Now Masterclass.

“I explained how IC could be introduced into the Australian market for general earthwork and asphalt paving,” he says. Additionally, Dr. Lee walked attendees through demonstrations of IC data collection in the United States, using the Veta software developed by the Transtec Group in Texas.

“This technology is readily available, so there is really no reason not to use it – I want to demystify the process and minimise hurdles to access,” Dr. Lee says.

“As with any new technology, contractors have to see it working on projects similar to theirs to believe it can work.”

A key feature of IC enabled rollers is the on-board computer display, which Dr. Lee says facilitates efficiency by providing real-time feedback to operators on the stiffness of material and required number of passes.

“When compacting, operators have traditionally had to estimate how many passes are required to complete the job, which can led to over-compaction,” Dr. Lee says.

According to Dr. Lee, real-time feedback eliminates this problem and allows operators to work with an informed perspective.

“The feedback can then be used to pre-map the conditions of existing asphalt layers before placing the next compaction lift, which streamlines the whole process,” Dr. Lee says.

“Plus, everything is stored in the cloud, so if there are issues with work a couple of years post construction, the stakeholder can go back and examine all the relevant data.”