Construction World August 2016

PROJECTS AND CONTRACTS

ROAD BUILDING capabilities

Significant

Five member companies work simultaneously on the three works packages making up the contracts, which were awarded to Roadmac Surfacing by N3 Toll Concession (RF) Proprie- tary Limited (N3TC). Roadmac Surfacing established on site in January 2015 to start tackling the rehabilita- tion of the stretch from Warden to Harrismith and the Harrismith bypass. The company started working on the third component of the project, namely Harrismith to Van Reenen’s Pass, in August last year. Andre Meissenheimer, contracts man- ager at Roadmac Surfacing, says the project involves a heavy rehabilitation of the existing road infrastructure. One of the biggest challenges is the strict riding quality requirements of sections of Durban again highlight the significant road building capabilities housed within the Raubex Group. > Rehabilitation of sections of the strategic N3 corridor connecting Gauteng to the Port of

One of the biggest challenges is the strict riding quality requirements of sections of the rehabilitated infrastructure.

The company has deployed three paving teams on this project. Equipment deployed by each team includes a paver and Shuttle Buggy, a special material transfer vehicle, a three drum roller, a double drum vibratory roller and two pneumatic rollers. Roadmac Surfacing is joined on the project by Raubex Group’s Milling Techniks, which has deployed two recycling and milling units on the projects. Work on the 50 km long stretch from Harrismith to Warden includes the recon- struction of the truck lanes (slow lane) by recycling the existing pavement materials. The in situ base and sub base layers are pulverised and pre-shaped, before receiving the lime and cement stabilising agents, which are spread by hand. The sub base layer is processed with a recycling unit to a depth of 300 mm to reinstate a C3 quality layer. A 100 mm wide, 60 mm deep key is cut into the pavement of the existing fast lane and materials removed. This creates a keyed joint between the adjacent fast and slow lane pavement structures. Meissenheimer says that a 60 mm bituminous base with modified binder is then placed to reinstate the pavement to the orig- inal level. The full width of the pavement is then finished off with a 40 mm A-R1 overlay. On the Harrismith to Warden stretch and

the rehabilitated infrastructure. It calls for a high performance asphalt mix which is being produced by National Asphalt, a member company of Raubex Group. “There is limited margin for error on the programme. Both companies, Roadmac Surfacing and National Asphalt, have to be very proactive and monitor materials produc- tion every day,” says Meissenheimer. He says the asphalt being produced for this contract has a five year guarantee, and is being batched at two plants built by Comar. The plants were supplied by subsidiary B&E International, the contract crushing arm of the Group that also specialises in large processing plants. National Asphalt is batching 800 t of material a day to meet the production requirements. Harrismith to Warden Roadmac Surfacing will place 40 000 t of bitumen treated base (BTB), 2 000 t of coarse graded asphalt mix as per TRH8 (TRH8) and 116 000 t of rubber bitumen asphalt (A-R1) for the Harrismith to Warden section. The Harrismith to Van Reenen section will consume 6 000 t of BTB, 17 000 t of TRH8, 24 000 t of ultra thin friction course (UTFC) and 13 500 t of A-R1, while the Harrismith bypass section requires 6 000 t of BTB and 12 500 t of A-R1.

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Road Techniks is just one of a number of Raubex companies operating on this project.

“There is limited margin for error on the programme. Both companies, Roadmac Surfacing and National Asphalt, have to be very proactive and monitor materials production every day.”

CONSTRUCTION WORLD AUGUST 2016