A lack of preventive maintenance is by far the biggest contributor to the deterioration of the South African road network, says South African National Roads Agency Limited (Sanral) engineering executive Louw Kannemeyer.

“It is purely because the infrastructure is not being maintained. And, because we don’t have a zero-maintenance design on our roads, we are seeing a rapid deterioration in the network.”

Kannemeyer adds that many South African roads are reaching the end of their design life, which means that they will be increasingly sensitive to a lack of maintenance.

South Africa has a proclaimed road network of more than 618 000 km.

Sanral is responsible for 22 262 km of the country’s roads at present. The agency’s network carries about 35% of yearly vehicle kilometres travelled in South Africa, but 70% of the long-distance road freight.

The rest of the country’s network falls under the ambit of provincial and municipal authorities.

It Doesn’t Pay to Do Nothing

Kannemeyer says there are two approaches to road maintenance.

The first is preventive maintenance. This is where Sanral, or a provincial or local authority, builds a road. Then, after seven to ten years, dependent on the climate and traffic, fine cracks develop, and the road surface must be waterproofed.

“To do that you need professionally qualified people,” says Kannemeyer. “You need engineers who understand what those cracks mean, who understand the climate of the area and the road design.”

If the relevant authority does not act to fix these cracks, secondary defects will likely develop after three to five years.

To repair the road will now cost six times more than what would have been the price tag to roll out the correct preventive maintenance, says Kannemeyer.

If left for five to eight years, fixing the road will now cost 18 times more, he notes.

“When a road is in a very poor condition, you don’t need to be an engineer to see that it’s in a poor condition,” says Kannemeyer.

“The reality we face is that a lot of authorities do not have professionals in their employ. The way [road] networks are currently being managed is to fix the worst first. [Authorities] wait for the road the most people complain about, and that is the one they’ll try and fix.”

However, following that strategy means that for every one kilometre of road repaired, the authority could have resealed 18 km of road, explains Kannemeyer.

“With the worst-first approach, the road cracks, and nothing gets done. Drains silt up, become blocked, and nothing gets done. The grass grows on the edge and it isn’t cut to allow the water to drain. Everybody then waits for potholes to develop.

“In the scenario of preventive maintenance, cracks are sealed, the grass is cut, the drains are cleaned – routine maintenance. That is a big focus area for Sanral.”

To cut grass and seal cracks cost about R9.50/m2 a year on average, says Kannemeyer.

“However, that buys you so much more in terms of asset life.”

Resealing costs are R70/m2 to R150/m2 every ten years.

To repair a pothole on a busy road is one of the most expensive exercises and can range from R700/m2 to R25 000/m2, says Kannemeyer.

The cost of accommodating traffic and closing lanes is ten times more than the actual repair work.

“You need to prevent the development of potholes at all costs – this is asset management,” says Kannemeyer. “And to do this, you need up-to-date data to ensure professionals can make informed decisions. At Sanral, we carefully track the deterioration of our roads.”

Cheaper Methods, so Maintenance Is Vital

When Sanral designs a road pavement, the agency does not design it for a number of calendar years, but rather for the traffic expected over the design period, which is typically 20 to 25 years.

Sanral will typically forecast the traffic over a 20-year period, says Kannemeyer, most notably the heavy-truck traffic.

This will determine the number of lanes – climbing lanes, passing lanes – and it will also dictate the kind of road pavemen...