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I am on a committee for the National Ready Mixed Concrete Association (disclaimer - I am not employed by them and none of this reflects their official positions) dealing with how to get performance specifications for ready mixed concrete into the Building Code. I know lots of people and groups are exploring performance specs and I thought this group might point me into the right direction for an official engineering point of view on performance specs for concrete.

In a nutshell, the intent of our subcommittee is to get designers to stop specifying prescriptive characteristics of concrete, such as minimum cement content, maximum water/cement ratio, maximum fly ash ratios, etc. and get them to specify performance criteria such as minimum strength, abrasion resistance, freeze-thaw cycles, maximum shrinkage, permeability, etc.

Members of the committee would also like to get away from having to submit mixture proportions, since many of the larger companies have spent a lot of money on QC and research (especially for self-consolidating concrete) and consider their proportions to be proprietary. There is a precedent for this. Materials Service, during the heyday of high strength concrete in Chicago, would not provide mixture proportions with submittals.

Here are my questions:

1) Is there an "official" ASCE or SEA position on performance specifications? If so, where can I find it?

2) What characteristics would engineers need to specify to be assured of getting the performance they need?

3) Would you, as a professional, be willing to pass off to the producers the right to set and adjust proportions as needed?

4) What could the producers do to eliminate the need for them to submit mixture proportions?

5) Are design engineers (who often receive little formal training on materials and operations) qualified to specify non-performance related criteria? (Don't shoot me, I'm just asking.)

6) Do design engineers really know what characteristics they need in concrete?

7) Any other backlash, rant or intelligent discourse you have to offer.

I thank you for your attention.

Jay Shilstone




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