Sanral explains why SA will always have potholes

The persistent rains in recent months across large parts of Gauteng and the northern provinces have again led to frustration among road users who have to deal with potholes, mostly on roads that are not managed by Sanral, the roads agency has said in a statement.

However potholes are not unique to South Africa, with citizens in Brisbane, Australia and across Canadian recently expressing their displeasure at “calf-deep” potholes and having to manoeuvre through “obstacle courses”, said Sanral network manager, Louw Kannemeyer.

“These examples also demonstrate the rolof weather conditions as important contributing factors in the development of potholes,” said Kannemeyer.

The leading cause of potholes on SA roads

“In warmer climes, such as South Africa, the beating sun results in surfacing layers drying out and becoming brittle, which results in cracks developing in the surface layer,” said Kannemeyer.

“If no maintenance is performed on these cracks, then with the next rains, water is able to penetrate through these surface cracks to reach underlying crushed rock and gravel layers that are used in the construction of most South African roads.”

“These crushed rock and gravel layers reduce the cost of road construction in South Africa by nearly 40% when compared to countries in Europe and the United States. The downside, however, is that as soon as these crushed rock and gravel layers become moist, they lose most of their strength, and along with that their ability to carry the imposed tyre loads, which results in the formation of potholes.”

According to Kannemeyer this ingress of rainwater through the surface is the leading cause of most potholes on South African roads, and that is why most potholes appear after prolonged periods of rainfall.

He also noted that this is why potholes are more prevalent on roads in wetter provinces of South Africa such as Mpumalanga and KwaZulu-Natal.

Preventative measures

Sanral’s currently policy is “preventative” said Kannemeyer, and has been at the core of SANRAL’s approach to managing the 21,946 km of national roads under its jurisdiction.

“This includes the opening and clearing of blocked storm water pipes and culverts, the cutting back of vegetation, the collection of litter and debris and the repair and reshaping of gravel shoulders,” said Kannemeyer.

“The next focus of our daily activities is to identify any surface cracks that have developed and seal them as soon as possible. Each of the 21,946 kilometres of national roads is covered by a three to five-year routine maintenance contract to perform the abovementioned daily activities.”

“As a result in addition to being 18 times cheaper than following a reactive maintenance approach, there should be an bovious difference when motorists compare the number of potholes they encounter on a SANRAL national road, to the number of potholes on roads managed by other authorities,” concluded Kannemeyer.

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