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Alexander McKay, Rafeek Louw and Adrian Bergh |
Building an ultra-thin reinforced concrete road |
Technology that involves ultra-thin, reinforced concrete roads has been developed and tested successfully by the CSIR over the past few years.
The technology is based on the observations of CSIR consultant Adrian Bergh during a visit to an experimental thin concrete road (100 mm thick) consisting of unreinforced and mesh reinforced sections, while attending a low-volume roads conference in Iowa, USA. He was impressed by the performance of the mesh reinforced section after some 15 years of traffic when compared to the unreinforced sections.
Towards the end of 2001, the CSIR participated in a thin concrete road experiment at a quarry near Krugersdorp. Three sections of reinforced concrete pavement were constructed - one section 100 mm thick, one 75 mm and the third section 50 mm. The performance of the 50 mm section exceeded all expectations and after more than six years, it is still in use and performing remarkably well. It was thus decided to promote the technology associated with the construction of 50 mm thick ultra-thin reinforced concrete pavement in roads.
A 2,5 km access road to a quarry outside Mthatha was completed at the end of 2008, with the Eastern Cape Department of Roads and Transport as client. "This road not only provides an all-weather surface to the local quarry, but has also improved the lives of communities along the road by curbing dust, providing access to their properties and reducing damage to their vehicles," explains Rafeek Louw of the CSIR.
The Gauteng Department of Public Transport Roads and Works has identified this technology for its roads upgrading programme. The department decided on demonstration projects in Soshanguve and Mamelodi in the Tshwane Metropolitan Municipality. "A 1,2 km bus route was completed in Soshanguve in December 2008," says Louw, adding "Construction has started in Atteridgeville and will commence shortly in Mamelodi."
Due to the success of the technology, the Gauteng department has decided to use it for its other road upgrading projects.
Evaluation programmes are being undertaken by the CSIR, the University of Pretoria and the Gauteng department using the CSIR-developed heavy vehicle simulator and other testing equipment and tests. "The preliminary findings indicate that this technology could be suitable for the construction of roads within the jurisdiction of the provincial roads authorities," comments Louw.
This type of pavement has a number of benefits, including:
- It lends itself to construction by labour using light plant and equipment, which not only involves the local community and creates employment opportunities, but is also suitable for small contractors
- It requires minimal maintenance; indications are that it has a life span of 30 to 40 years, resulting in reduced life cycle costs and disruption to road users
- Its construction cost is comparable to that of conventional 'blacktop' roads.
Enquiries: CSIR Communication
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