Many countries around the world depend on thousands of concrete bridges, roads, and buildings that look solid from the outside. But some of the most serious damage may be happening where no one can see it, as moisture and salt reach the steel reinforcement inside. About five million tonnes of road salt are used on Canadian roads each year, according to Environment and Climate Change Canada. Coastal saltwater and everyday moisture create the same risk worldwide, making this a global infrastructure challenge.
Corrosion gradually weakens the steel that gives reinforced concrete its strength. It can progress for years without obvious warning signs on the surface. Statistics Canada reports that replacing Canada’s road transportation infrastructure rated in poor or very poor condition, including bridges and tunnels, would cost an estimated $250.2 billion. If deterioration is missed, it may lead to costly repairs and, in severe cases, put lives at risk.
Many inspections still rely on drilling core samples and taking point-by-point corrosion readings. These limited methods are labor-intensive and expensive, and they often require closing roads or bridges for days. They also test isolated spots, which makes it hard to understand the condition of an entire structure. For a bridge several kilometers long, a few samples may reveal very little about what is happening across the rest of it.
The bigger problem is scale. Infrastructure owners may be responsible for thousands of structures, yet they cannot inspect them all in detail or treat them all as equally urgent. New materials, such as galvanized or non-metallic reinforcement, may reduce corrosion in future construction. But thousands of existing structures built with conventional steel will remain in service for decades.
Alex Tarussov, geophysicist and founder and CEO of RadEx, a Montreal-based engineering firm, has spent more than 30 years working with ground-penetrating radar. Engineers have explored using the technology to map corrosion for decades, and an industry standard for the method was introduced in the 1990s. In Tarussov’s view, that early approach was too simplistic to produce reliable results. “By the late 2000s, many practitioners recognized a different method was needed,” he says.
According to Tarussov, RadEx’s approach took shape in 2008, when the company was asked to produce an accurate corrosion map of a concrete slab following a fatal structural collapse in Montreal. Rather than relying on basic signal measurements, the team analyzed the radar images directly. “We approached it like a doctor reading an X-ray,” Tarussov says. “You look at the image and identify where the problem is.” He notes that the resulting map was verified as accurate, and RadEx later developed software that brought the method into routine use by around 2013.
Today, the company uses vehicle-mounted ground-penetrating radar to scan structures at highway speeds, often without closing them. The technology can map areas of potential corrosion across entire decks, rather than at isolated points. Tarussov says the company has analyzed more than 100 structures, including bridges several kilometers long. He also points to rapid advances in radar equipment, which can now record detailed data at far higher speeds than systems from 15 years ago.
Tarussov believes inspections should guide repair plans, not follow them. Faster screening may help owners see which structures are in good condition, which need monitoring, and which need urgent attention. That could help direct limited maintenance budgets to where they are needed most. “Out of a thousand structures, you can identify the ten that need attention first,” he says.
In Tarussov’s view, the greatest obstacle is not the technology, but the industry’s reluctance to change. Engineers and infrastructure owners often continue using familiar methods, even when newer approaches are available. He adds that modernizing infrastructure management will require trust in better tools, as well as the tools themselves. “The technology is ready,” he says. “The challenge is getting the industry to use it.”
Reinforced concrete built today will remain part of global infrastructure for generations. Future materials, like galvanized or stainless steel, may help, but they cannot fix the deterioration already present in existing structures. For Tarussov, the future of maintenance depends on finding hidden damage earlier and making decisions based on better evidence. Infrastructure cannot be protected effectively if no one can see what is happening inside it.
