Concrete crash barrier - Concrete cental crash barrier on m6

[Mikee]

Driving up the M6 between Junctions 33 & 34 in the Road works I saw a machine that was making a continuous concrete barrier. The barrier looks to be about one metre high with a step out at the base. The thing is I couldnt see any shuttering or reinforcement, how does this work? Why doesnt it slump?

[centralcrushers]

They use a very dry, quick setting mix that is formed by a "shoe" that moves very slowly. It places, shapes and vibrates the mix, after which the final trowelling is finished by hand.

[msh paving]

this is the machine you are talking about
look at me

MSH

[Mikee]

Thanks to Central Crushers and MSH Yes that looks like the machine. I did see someone floating the barrier about 20 yards away.

[dig dug dan]

they have just done the same thing on the M25 and M1. Except when i saw it, there was someone filling in large holes with a barrowload of muck and a shovel! ???

[GB_Groundworks]

featured a crew in earthmovers a few months back they had the latest slip form machine could do the central barriers and the shallow v profile drains, they had 2 guys with stihl saws following cutting expansion joints, 1 inch steel cable is incorporated into the concrete for reiforcement to stop big wagons etc. they were taking a 100mm cube of each load of concrete for reference and testing.

[Dave_L]

This is the type of slip-form paver they used down here in Somerset to construct the cross-over barrier.

[seanandruby]

Used a slipform shutter once to line a shaft 11 metres wide and 30 metres deep. Shutter moved up slowly, continuously. There were men hanging below on a falsework deck bagging up as we went. took 3 weeks to complete. Could only have 2.5metre lorries as the concrete went off too fast.

[mickg]

seen it used a the start of the M61 a few months back, in a few places they had removed the surface due to a bad finish and used a steel form to the same shape for making good any patches

[Tony McC]

The machines are popular in that America, so they suffer under the name of "Power-Curber" (sic)

[Big Phil]

aye, getting more popular on motorways due to speed of volume placed. concrete needs careful design - with v.little variance in consistence.

[Mikey_C]

just did a section of M27 with it as well difficult to watch unless there has been an accident in the road works, so i got to look at it quite a bit!!