Re: [greenyes] Specs for plastic lumber for highway posts

[Alan Muller <amuller@no.address>]

At 11:12 AM 1/3/2005 -0600, Reindl, John wrote:
> Does anyone know of test data for plastic lumber for use as highway sign or
> crash barrier posts?

King County (Washington State) and the City of Seattle have experience with 
this and there is info at: http://www.metrokc.gov/procure/green/plastic.htm

ASTM has adopted a whole set of structural standards for plastic lumber.  I 
haven't tried to use them so I don't know how helpful they are.


> My Highway Commissioner said that the ACQ treated posts that they are using
> for signs are not working, as the aluminum signs and metal bolts are rapidly
> corroding -- to the point of the signs falling off the posts after six
> months.

This is very likely, but should be preventable by using stainless hardware 
and shimming the signs away from the posts with inert pads.

> The Highway Department would like to try plastic lumber posts, but need test
> data -- especially "break away ability'' -- to show that they are suitable.

My impression is that "plastic lumber" is extremely variable in 
properties.  It needs to be matched carefully to the intended use.

Alan Muller