Trials with rubberised asphalt in South Africa prove successful
South Africa Gets First Rubberised Asphalt Road
South Africa may soon adopt a new kind of road after a trial with asphalt that contains recycled tyres and locally available additives, proved to be a success.
The Council for Scientific and Industrial Research (CSIR) – in partnership with Much Asphalt, the largest commercial asphalt producer in southern Africa – constructed a road with the new kind of asphalt in Roodepoort in November last year.
It was the result of many years of research, says Georges Mturi, manager of CSIR’s Advanced Material Testing Laboratories.
South Africa needs a cheaper way to pave roads – which also needs to withstand the increasingly heavy traffic levels and loads. The traditional bitumen used for South African tarred roads is currently strengthened with expensive imported polymers, says Mturi.
The CSIR attempted to find a cheaper way, and after years of research found a blend of recycled waste tyre crumb and a mixture of cheap microfillers, inexpensive locally mined products. It was used for the Roodepoort road section, a 200metre-long stretch which connected the Much Asphalt Roodepoort branch to a public road tie-in.
The road was close to a weighbridge and saw a constant flow of traffic. A year later, it is clear that the trial was a success, says the CSIR.
“To date, no edge breaking is present where heavy vehicles are moving onto and off of the surfacing. There is no permanent deformation present on the surfacing, with a particular focus at stopping locations or where vehicle turning takes place and, to date, there are no signs of any deflection or temperature-induced crack formation taking place,” said Joanne Muller, Much Asphalt regional laboratory manager.
The 200 m-long trial section included a 60 mm modified “enrobés à module élevé” (EME) base layer and a 40 mm modified bitumen rubber surfacing layer that was constructed over a cleaned gravel base layer treated with an SS60 tack coat prior to paving.
The new mix, which includes recycled tyres, can help to bolster low-grade quality bitumen. It will also assist South Africa in producing specific asphalt mixes in the event of national bitumen shortages.
A significant benefit of this invention will be an increase in the recycling of waste tyres, says the CSIR.
Mturi says the new development will be promoted into national standards in the construction industry, and he hopes that the road authority will also embrace it in the future.
Source: Business Insider SA