Recycled resin and AASHTO
I am writing to express my disappointment in your Comment in the November issue. The editorial amounted to an endorsement of a product that is still untested outside the facilities of the manufacturer. The endorsement was given without due consideration to the impact of this product and on AASHTO’s efforts to ensure the quality of HDPE pipe.
My employer, a manufacturer of HDPE and corrugated steel pipe, supports the LEED program. We also support the use of products that conform to applicable specifications.
AASHTO, in conjunction with the HDPE pipe industry, has been engaged in an ongoing effort to improve the quality of HDPE pipe and minimize product variability. AASHTO M294 was the result of years of research and testing, mostly funded by AASHTO. Now a mysterious product, wrapped in a cloak of green and with unknown performance and quality, is being considered concurrent with efforts to further improve the quality of HDPE pipe.
Additionally, your article mentioned other pipe incorporating recycled materials but neglected to mention corrugated steel pipe (CSP), which has a recycled content ranging from 25 percent to 75 percent, depending on the steel-making method used. Unlike HDPE pipe made with recycled resins, CSP is a product that has been around for more than 100 years and is widely available from many fabricators.
It is a proven product that always has had the same recycled content and will have it tomorrow.
Russell A.Kamper, P.E.
Camp Hill, Pa.
Thanks for sharing your comments. Please note that I did not intend to endorse HDPE made from recycled resins, but to describe the state of affairs in regard to a product, including that there is debate surrounding its use and that AASHTO has funded research to learn more about its performance and quality control. Additionally, the recycled content of corrugated steel pipe was not mentioned only because discussing the green merits of various types of pipe was beyond my scope. With limited space, I cited only one alternative and chose concrete pipe arbitrarily.
Shanon Fauerbach, P.E., editorial director
Many thanks for soil mechanics review
Your article in the December 2004 issue was well written, straightforward, and easy to understand.
It is perfect for those engineers who routinely are responsible for such activities. I have been looking for a great explanation of this important aspect of earthmoving contracts. I will use it in my consulting engineering practice.
Thanks for the contribution to civil engineering.
Michael R.Simac, P.E.
Good article in the CE News on shrink/swell of fill. I had an argument a few months ago with a contractor about this very subject. If I had this article in hand, the argument would have been cut short!
Thank you for putting out such a practical article on this important civil engineering subject. The article is based upon sound elementary soil mechanics, and is a great reminder that costly mistakes are often tied to a lack of simple theory.
Gary Kellogg, P.E., S.E.
Alfred Pagan, P.E., P.L.S.’s article in the December 2004 issue insinuates that contractors are allowed to take it upon themselves to provide an alternate material or product without seeking approval from the owner or agency. don’t the agencies that allow this have a submittal approval process established? Where I work at Tri County Metropolitan Transportation District of Oregon, if an alternative is submitted by the contractor to use in the project, the submittal is sent to the design engineer to approve or disapprove. So, the possibility of the engineer of record not being aware of a product or material change is eliminated.
While spending federal funds in our projects, we are careful to review and approve submittals for all materials to ensure project success is shared by all—agency, design engineer, and contractor—as a team.
The alternate specification policy I was referring to is one in which specifications are written and inserted into the design documents after the original designer has presented his design to the authority for which he or she works. I am sure that there are many ways in which alternate specifications can be implemented. The procedure you described is better than the one I have seen, which does not allow the original designer to get involved in the selection process.
Alfred R. Pagan, P.E., P.L.S.
I will agree with Pagan, if he clarifies that his perspective is in regard to "leading edge" technology or "unique" designs. Otherwise, I think that most construction engineers would agree that designers tend to be myopic, rarely take the time to learn new products, and are somewhat inflexible when asked to review an alternative.
This leads us to wonder if the designers are qualified to review alternatives or are just reissuing the same approach on as many projects as they can make it fit. At the same time, the material cost is the contractor’s risk (owners and engineers don’t want any responsibility) and usually variable, especially when the material cost is tied to crude oil prices.
A designer once told me to just go build per the plan, that he didn’t have time to review alternatives. For this same project, he specified an aggregate gradation that had to be transported from an hour away, with several pits nearby the site. (We tried blending but couldn’t meet "his" gradation.) And how about the out-of-state designers who don’t even check local available materials, but just refer to same old same old? Anonymous
You make some very valid points regarding the advantages of alternate specifications; I can’t dispute them. Perhaps I have been accustomed to their use in a poor manner. So far, the e-mails I received have disagreed with my viewpoint. I believe both sides of the issue have valid points.
Alfred R. Pagan, P.E., P.L.S.