The Civil Engineering Contractor June 2018 | Page 3

COMMENT What’s potting with our roads? W hy is it that as soon as we have any significant rain, our roads literally fall to pieces as sinkholes occur and, on a smaller scale (size- wise, but on a larger scale in frequency), potholes appear? According to the Council of Geoscience, South Africa, specific parts of the country’s ground surface are susceptible to sudden, disastrous collapse, which may lead to death, injury, or structural damage, depending on the size of the subsidence. Such features are known as sinkholes and they form in areas where soluble rocks below the surface, like limestone or dolomite, are dissolved by water. Approximately 25% of Gauteng Province, as well as parts of Mpumalanga, Limpopo, North West, and Northern Cape provinces, are underlain by dolomite and therefore susceptible to this hazard. For example, a massive sinkhole recently appeared near Daniëlskuil in the Northern Cape. An estimated cost of the damage caused by sinkholes to date is in excess of R1-billion. While sinkholes are memorable by their sometimes horrifyingly spectacular occurrence, those dreaded potholes, the scourge that accompanies the blessing of rain, are more of an irritant at the one end of the scale and a road hazard at the other end. The stupefying thing is, they never seem to go away; they reappear — often in the same place — despite being mended. Road construction teams are seen in clusters after the rain, diligently pouring asphalt into gaping holes and hammering it in place. Only to be seen again, at the same spot, undertaking the same task. Why? Read more about all manner of waterproofing on page 18, ‘Protecting infra from water ingress’, as well as in the Business Intelligence column, ‘A rethink on e-tolls’, where we interview SANRAL executive, Louw Kannemeyer, on page 36. nn Kim Kemp - editor [email protected] Speaking to Morné Jonker, CEO of MMS Group, he explains that fixing potholes permanently takes skill and expertise. “Not just anyone can fix a pothole. They think they can buy a bag of (ready-made) mix and toss it into the hole and use a hand compactor to compress it. It’s far more complex than that,” he adds. He stresses that it’s in the preparation of the hole. The sides must be cut, the cavity cleared of any sort of residue and debris, and once the mix has been poured into the hole and compacted, the cut edges must be sealed with a bitumen binding liquid, to prevent water ingress. “It’s not a case of simply ‘gooing’ it into the hole and thinking it’s going to last,” he adds with irritation. Competition is stiff, according to Jonker, who has a private company that offers a fit-and-supply pothole solution as one of its services to the private and public sectors. The problem arises that ‘pothole specialist’ companies are springing up like mushrooms after a storm, found on every corner, even from as far afield as Zimbabwe, undercutting the opposition and promising all manner of permanent solutions, Jonker maintains. Unfortunately, the unwary client only realises the degree of ‘permanence’ long after the contractor has disappeared — and the hole reappears. The upside here is that Jonker’s company is regularly approached to fix the mess left by other ‘specialists’. Some potholes are so urgently in need of repair, that you could be excused for mistaking them for sinkholes. CEC June 2018 - 1