The South African Road Federation (SARF) has welcomed Transport Minister S’bu Ndebele’s announcement that R22- billion has been allocated for the maintenance of the country’s deteriorating secondary road network.
The programme includes a pothole patch-work initiative which is to be rolled out immediately. SARF president, Mutshutshu Nxumalo, says it is essential, however, that the pothole repair work be carried out in accordance with best-practice repair standards. “Unless the fundamental causes of potholes are identified, the repair is likely to be inappropriate and of short duration,’ he says.
Nxumalo says potholes are often repaired on an ad hoc or reactive basis which is ineffective and far more expensive than planned and ongoing maintenance. He observes that it is common practice for roadside material to be used for pothole patching.
“The material is generally weak and water-sensitive and results in surface settlement, water ponding, cracking and the formation of new potholes.’
According to a recent technical brochure on the causes and effective repair of potholes published by the Council for Scientific and Industrial Research (CSIR), the underlying principle in pothole repair should be to provide the patch with the same or similar deflection properties as the original surface. Significant differences in deflection (the amount of movement under traffic loading) will lead to cracking at the interface between the patch and the road surface. These cracks allow the ingress of water and then further potholing.
The CSIR’s guidelines provide comprehensive information on the appropriate repair of the different categories of potholes. Aimed at provincial municipal, consulting engineers and road owners, it presents mechanisms for quality control in pothole repair and provides a standard format on the rating of potholes.
SARF estimates that pothole damage is costing motorists R50-billion in vehicle repairs and injury every year.
“This underscores the need for a comprehensive preventative maintenance programme which should be phased in as soon as possible. Roads begin to deteriorate from the day they are laid, not only due to traffic loading but to other factors such as temperature variances, UV rays and a loss of elasticity in the bitumen which leads to cracking.’
SARF also welcomes Ndebele’s pothole hotline initiative which will assist with their early identification. “The sooner potholes are identified theeasier and less expensive they are to repair,’ Nxumalo reckons.