New technology promises to reduce potholes

After every period of heavy rains, let alone floods, we yet again see that road quality matters — with poor construction leading to potholes and road subsidence. This can cause tire blowouts and structural damage to cars and trucks, as well as increase the chance of serious accidents.

To tackle this problem, researchers from the University of Technology Sydney have developed new “intelligent compaction” technology, which can be integrated into a road roller to assess in real-time the quality of road base compaction. As a result, it can reduce potholes and maintenance costs, leading to safer and more resilient roads.

Said technology uses an innovative machine-learning technique to process data from a sensor attached to a construction roller. The study was led by Associate Professor Behzad Fatahi, head of geotechnical and transport engineering, together with Professor Hadi Kahbbaz, Dr Di Wu, and Ph.D. student Zhengheng Xu.

“We have developed an advanced computer model that incorporates machine learning and big data from construction sites to predict the stiffness of compacted soil with a high degree of accuracy in a fraction of a second, so roller operators can make adjustments,” said Associate Professor Fatahi.

Generally speaking, roads are made up of three or more layers, which are rolled and compacted. The subgrade layer is usually soil, followed by natural materials like crushed rock and then asphalt or concrete on top. The variable nature of soil and moisture conditions can result in under or over-compacted material.

The adopted machine learning method incorporating Gaussian Kernel and Generalised Gegenbauer Kernel functions can reasonably predict the double-layered soil modulus during roller compaction. Researchers conducted additional analyses to observe the proper training size and number of iterations to achieve real-time quality control to be used by site engineers.

“Like Goldilocks, the compaction needs to be ‘just right’ to provide the correct structural integrity and strength. Over-compaction can break down the material and change its composition, and under-compaction can lead to uneven settlement,” added Associate Professor Fatahi. “A well-compacted multi-layer road base provides a stable foundation and increases the capacity of a road to bear heavy loads. Trucks can weigh up to 40 tonnes, so a poor quality base can quickly lead to cracks and weak spots in the asphalt surface.”

Researchers have published their paper in the peer-reviewed journal Engineering Structures, suggesting the application of this technology could help build longer-lasting roads that can better withstand severe weather conditions.

Now, the team is looking to test the technology onsite for various ground and roller conditions for road, railway and dam construction projects. Also, they want to explore techniques to measure the density and moisture content of the compacted soil in real time during construction.