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N3 Highway Rehabilitation - KwaZulu-Natal, South Africa

The rehabilitation site extended over two Highway Sections - Highway Section 2B2 N3-4, km 46.200 to km 61.600, and Highway Section 3 N3-5, km 0.000 to km 12.400.

 

Overview

WSP | Parsons Brinckerhoff and Aseda JV were appointed to undertake investigation, detail design, tender documentation and construction supervision of the rehabilitation of the N3 Highway Section 2B/2, 3 and 5C. Scope of works included rehabilitation of a portion of the N3 Toll Road, including Part 1 between Mooi River and Midway (28km), and Part 2 between the Sand River and Keeversfontein (9km).

Highway Sections 2B2 and 3 are dual carriageways with a surfaced width of 11.1m per carriageway (2.9m surfaced slow shoulder, 3.7m slow lane, 3.7m fast lane, 0.8m surfaced fast shoulder) (Median width 9.0m).

Challenges

Our client’s challenge was to maintain and protect the functional and structural characteristics of the road pavement, without the need for total pavement reconstruction for as long as possible.

Our Approach / Services

The primary rehabilitation work required on Part 1 Highway Sections 2B2 and 3 was heavy rehabilitation through the reconstruction of pavement layers, an asphalt inlay, application of an asphalt overlay, and application an Ultra-Thin Friction Coarse (UTFC). Further, the construction of a 3km climbing lane was undertaken to alleviate congestion and the significant speed differentials between heavy and light vehicles based on the two lane configuration. Further work included attending to drainage problems by constructing sub-soil drains next to the road pavement layer to prevent moisture ingress; construction of concrete-lined median and side drains with miscellaneous drainage work at various locations; and application of sprayed concrete to embankments at various locations. A 35mm asphalt overlay with 13.2mm rolled-in chips was applied to the interchanges.

The primary rehabilitation work required on Part 2 Highway Section 5C, was repair of concrete failures; application of an asphalt levelling course on identified sections to improve riding quality; construction of a 13.2mm bitumen rubber single seal (SAMI); and application of a bitumen rubber asphalt wearing course.

Ancillary works included construction of concrete-lined drains and improvement of the vertical clearance on the southbound carriageway at the Keeversfontein Interchange overpass.

Outcomes

We received a performance certificate from the N3 Toll Concession upon completion of the project.

Facts and Figures

Client: N3 Toll Concession

Project Date: February 2013 – April 2016

Project Fee: ZAR 22 million