Countries around the world rely on thousands of concrete bridges, roads, and buildings that appear strong and stable from the outside. However, some of the most significant damage may be taking place beneath the surface, as moisture and salt penetrate the steel reinforcement inside. Approximately five million tonnes of road salt are spread across Canadian roads each year, according to Environment and Climate Change Canada. Coastal saltwater and everyday exposure to moisture create similar risks worldwide, turning corrosion into a global infrastructure concern.
Corrosion slowly compromises the steel that provides reinforced concrete with its strength. The process can continue for years without producing visible signs of damage on the surface. Statistics Canada estimates that replacing Canada’s road transportation infrastructure in poor or very poor condition, including bridges and tunnels, would cost approximately $250.2 billion. When deterioration goes undetected, the consequences can include expensive repairs and, in more serious cases, risks to public safety.
Many infrastructure inspections continue to depend on drilling core samples and collecting corrosion measurements at individual points. These traditional approaches are costly, time-consuming, and often require roads or bridges to be closed for several days. They also provide information from only a handful of locations, making it difficult to assess the overall condition of an entire structure. On a bridge stretching several kilometres, a few isolated samples may offer little insight into what is happening across the remaining surface.
The challenge becomes even greater when considering the scale of infrastructure networks. Owners and operators may be responsible for thousands of structures, but inspecting every one in detail or assigning the same level of priority to each is rarely practical. New construction materials, including galvanized and non-metallic reinforcement, could help limit corrosion in future projects. However, thousands of existing structures built using conventional steel will continue serving communities for decades.
Alex Tarussov, geophysicist and founder and CEO of RadEx, a Montreal-based engineering firm, has spent more than three decades working with ground-penetrating radar. Engineers have been investigating the technology’s potential for corrosion mapping for many years, with an industry standard for the approach introduced during the 1990s. However, Tarussov believes the original methodology was too basic to deliver consistently reliable findings. “By the late 2000s, many practitioners recognized a different method was needed,” he says.
According to Tarussov, RadEx’s approach began taking shape in 2008, when the company was asked to create a precise corrosion map of a concrete slab following a fatal structural collapse in Montreal. Instead of depending on basic signal measurements, the team focused on examining the radar images themselves. “We approached it like a doctor reading an X-ray,” Tarussov says. “You look at the image and identify where the problem is.” He explains that the resulting map was confirmed to be accurate, and RadEx subsequently developed software that made the methodology suitable for regular use by around 2013.
Today, RadEx uses vehicle-mounted ground-penetrating radar systems to examine structures at highway speeds, frequently without requiring road closures. Its technology can identify and map potential corrosion across entire bridge decks rather than depending on measurements from isolated locations. Tarussov says the company has assessed more than 100 structures, including bridges extending several kilometres. He also highlights how much radar equipment has advanced, with modern systems capable of capturing detailed information at considerably higher speeds than equipment available 15 years ago.
Tarussov believes inspections should determine maintenance priorities rather than simply being carried out after repair plans have already been established. More efficient screening can help infrastructure owners distinguish between structures that remain in good condition, those requiring continued monitoring, and those needing immediate intervention. This approach could allow limited maintenance budgets to be directed towards the areas where they will have the greatest impact. “Out of a thousand structures, you can identify the ten that need attention first,” he says.
From Tarussov’s perspective, the main barrier to progress is not a lack of technological capability, but the industry’s resistance to adopting new approaches. Engineers and infrastructure operators often continue relying on established inspection practices, even when more advanced alternatives are available. He believes improving infrastructure management requires both confidence in modern technologies and a willingness among industry professionals to embrace them. “The technology is ready,” he says. “The challenge is getting the industry to use it.”
Reinforced concrete structures being built today are expected to remain part of the world’s infrastructure for generations. While alternative materials, including galvanized and stainless steel, may help reduce future corrosion, they cannot address the deterioration already affecting existing structures. For Tarussov, the next stage of infrastructure maintenance depends on detecting hidden damage sooner and making decisions supported by more accurate information. Protecting infrastructure effectively begins with understanding what is happening beneath the surface.
