Construction World October 2016

ROADS AND BRIDGES

Roughness Index (IRI) requirements. Uneven sections are milled out using a planer. Koch says the machine is equipped with eight sensors to accurately detect uneven surfaces. These sensors also help guide the machine in removing on average 0,6 mm of BTB with its drum that is equipped with 750 teeth. “The accuracy of the final layer of the BTB is critical, as it will influence the layer of UTFC that is placed on top of it, and if not 100% could compromise the high rideability specification demanded by SANRAL,” he says. A very high specification UTFC is being used on this project. It is a proprietary product of National Asphalt that carries a three year warranty, and is known for reducing rutting, minimising spray in rainy seasons and providing a very high skid resistance. Roadmac Surfacing and Raubex are working hard to ensure that their road projects point to the quality that is associ- ated with the skills deployed from Kenneth Kaunda Road Extension, Cleveley, and is adopted throughout the country and across its borders. This project is no exception and is certainly on its way to becoming a flagship project in the group’s impressive portfolio.

LEFT: Roadmac Surfacing is ahead of schedule and the project will be completed before deadline. RIGHT: Roadmac Surfacing’s component of the project focuses on the surfacing aspects of the project.

site. Because it is a large contract, small problems, such as those encountered at the asphalt plant, can become very large challenges,” says Koch. High rideability specification The high rideability specification requires careful application of the BTB and UTFC. Two 60 mm layers of BTB are placed sepa- rately and individually inspected to ensure the final layer meets the tight 10,5 International

placement of the UTFC. Ongoing commu- nication enabled the companies to bolster their teams to ensure that the construction programme remained on track. These mitigating efforts were definitely worth it, considering that, by mid-July, the company had already completed 81% of its component of the project, and had not yet recorded one asphalt failure. “The project relies heavily on achieving a repetitive rate on the construction

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CONSTRUCTION WORLD OCTOBER 2016