PROJECT PROFILE Coating Refurbishment of Domain Tunnel Ventilation Stack, Melbourne Transurban’s Grant Street Ventilation Stack for the Domain Tunnel has recently been refurbished by Mattioli’s industrial coating team. The Stack is close to 50 metres high and nearly 8 metres in diameter. The Domain Tunnel is a road tunnel Consultancy KTA-Tator Australia Pty Ltd located in the centre of Melbourne carried out an initial inspection report which carries traffic westbound from of the coatings and corrosion condition the Monash Freeway to the West of the Grant Street Vent Stack. “The Gate Freeway. This and the eastbound structural steelwork and metalwork of Burnley tunnel are part of the the vent stack was shop-coated before CityLink Tollway network operated by erection with a zinc primer, epoxy Transurban and provides a bypass of the intermediate and polyurethane topcoat central business district. Emissions from system, with most structural members these tunnels are discharged via two coated with a bright red (believed to be ventilation stacks, one being the Grant Cherry Red) colour.” Street Ventilation Stack. Mark B. Dromgool, Managing Director The primary objectives of the works of KTA-Tator highlighted “Tension rods were to repair corrosion to the red and their clevis plates are typically steel elements of the structure and to coloured aluminium. Records indicate repaint the red steel elements and the that the protective system was applied black tubular column in accordance around 2000, meaning it is now with the drawings and specifications between 15 and 17 years old. The outlined by Transurban. coating system is still quite sound for p.50 CORROSION & MATERIALS PROJECT PROFILE its age, suggesting it was generally Mattioli’s initial start to the project was mastic and a 75 micron top coat of quite well applied. The gloss level of to water jet clean all surfaces (including high build recoatable polyurethane the red topcoat has dropped to quite the concrete core) using high pressure (Weathermax HBR). an extensive degree, especially on potable water at 4,000 psi (27.6 Mpa). the western and northern sides of the The next crucial task involved spot The client praised Mattioli at the end structure and of individual members. power tool cleaning of all areas that of the project on another successful Some quite noticeable chalking of the showed signs of rusting, under film and professional outcome. This was topcoat has also occurred on the same corrosion, poor adhesion which were due to an ahead of schedule date orientations.” The localised degradation cleaned in accordance with SSPC-SP 11. of completion and no complaints is consistent with wind borne sea from the public residing next to the salt from Port Phillip Bay and solar A key area of the works was to repair ventilation stack. irradiation on the northerly aspects. corrosion to the red steel sections, Chalking damage on the surface was starting with 75 microns of an epoxy Case study submitted by Mattioli – due to weathering and the paint binder zinc rich spot primer (Zincanode 402) Innovators in Protective Coatings, slowly being degraded by sun and to prime the most affected areas who are a leading moisture. When it came to a coating followed by a spot intermediate coat protective coating renewal, it was essential a new system of epoxy mastic (Durebild STE). The applicator in had a UV stable top coat for long term prepared steel then received a full 80 Australia, based durability and colour retention. micron intermediate coat of the epoxy in Victoria. August 2017 www.corrosion.com.au p.51.