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Rusty Concrete Barriers and Bridges

  • 19-08-2015 8:30pm
    #1
    Moderators, Social & Fun Moderators Posts: 12,366 Mod ✭✭✭✭JupiterKid


    Has anyone else noticed that quite a lot of the concrete median barriers on our motorways are taking on a reddish hue? This applies to a lot of the bridges as well.

    What's the cause? Iron leaching out of the concrete in our damp climate? Do you think it looks unsightly? What are (if any) the solutions? Painting them?


Comments

  • Registered Users Posts: 564 ✭✭✭annfield1978


    worked on the design of the N4 KEK PPP Scheme and the bridges there are riddled with it, bolts used to secure parapet guardrail reacting with concrete parapet?


  • Registered Users Posts: 1,741 ✭✭✭BowWow


    worked on the design of the N4 KEK PPP Scheme and the bridges there are riddled with it, bolts used to secure parapet guardrail reacting with concrete parapet?

    Its also very noticeable on the central concrete barriers on several of the motorways - wouldn't think there'd be any bolts in them?


  • Registered Users Posts: 4,801 ✭✭✭Poxyshamrock


    I noticed this on the M7 last week as well. It's also noticeable on houses that aren't painted.




  • I had a similar reddish "bloom" on some concrete walls of my house and a poster in the "DIY" forum said that it was a fungus that lives off the one of the constituents of the cement (or something like that) he suggested a 50:50 Bleach : water mix sprayed over the wall will clear the reddish tinge.

    I tried it and it worked!


  • Moderators, Business & Finance Moderators, Motoring & Transport Moderators, Society & Culture Moderators Posts: 66,532 Mod ✭✭✭✭L1011


    There's two different potential causes here

    1: Rust from a metallic source - bolts, iron in the aggregate
    2: Red dust

    The latter is extremely common around North Kildare and also affects houses, roadsigns, etc, etc.


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  • Registered Users Posts: 2,091 ✭✭✭marmurr1916


    It's just lichen or a fungus. No big deal. Personally I think it softens the harshness of a raw concrete surface.


  • Closed Accounts Posts: 106 ✭✭Quadrature


    Ireland's very damp and basically everything is naturally covered in lichen.

    It's one reason why bare concrete or plaster is a very poor choice of external finish here.

    Those central medians will turn brown then brownish green as lichens coat them. I don't think it's ugly, it's just how the ecosystem works in this climate.

    In most other climates, hot sun or intense frosts limit / eliminate lichens entirely.

    I really wouldn't suggest going crazy bleaching it. It would cause bleach runoff into the environment via surface water drains.

    In Cork due to the extremely mild climate a lot of road signs turn moss / lichen covered and need power washing every so often!

    Moss will even grow on the boot and door rubber seals of your car down here and we've had miss lift roof slates.


  • Registered Users Posts: 474 ✭✭The Megaphone


    Quadrature wrote: »
    I really wouldn't suggest going crazy bleaching it. It would cause bleach runoff into the environment via surface water drains.

    Rumour has it washing up liquid does the job in getting rid of it.


  • Moderators, Business & Finance Moderators, Motoring & Transport Moderators, Society & Culture Moderators Posts: 66,532 Mod ✭✭✭✭L1011


    Rumour has it washing up liquid does the job in getting rid of it.

    Also something you don't want running off to the water table uncontrolled.


  • Registered Users Posts: 8,779 ✭✭✭Carawaystick


    Rumour has it washing up liquid does the job in getting rid of it.

    Why would you not want vegetation to soften bare concrete?


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