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RE: Performance specifications

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Jay,

It has been a while, but Jim Shilstone and I had many discussions on this
topic.  Now to your specific questions:

	1) Is there an "official" ASCE or SEA position on performance 
	specifications? If so, where can I find it?  
	I am not aware of any position.

	2) What characteristics would engineers need to specify to be
assured of 
	getting the performance they need?
	Some characteristics that immediately come to mind are: strength
(compression, and modulus of rupture) at various ages (7, 14, 28, 90 days),
density at 7 days 28 days and at equilibrium, modulus of elasticity,
durability (freeze / thaw, abrasion, etc.), shrinkage (plastic and drying),
workability (your father's specialty), sulfate resistance, chloride
resistance, other chemical resistance, heat / fire resistance, set times,
set characteristics, bleed water characteristics, ability to consolidate for
the given reinforcing and placing methods, pumpability, heat of hydration,
finishability for flatwork (can it be steel troweled, magnesium troweled, or
flat finished at all), can it be placed underwater, rebar corrosion
characteristics (like for silica fume, or DCI), cure time and methods,
acceptance criteria for all aspects of testing, resolution criteria for
strength / cylinder tests (how are the cylinders stored in the field), are
cubes or cylinders to be used for strength confirmation. 

	3) Would you, as a professional, be willing to pass off to the
producers 
	the right to set and adjust proportions as needed?  
	Yes, as long as there were clear ASTM definitive tests to
corroborate performance.

	4) What could the producers do to eliminate the need for them to
submit 
	mixture proportions?
	Conform to the specs.  There is a very spotty regional history of
compliance to the specifications as they currently exist.

	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.)
	Not generally.  Most engineers do not understand even the basic
acceptance criteria for mix design confirmation cylinders vs. evaluation and
acceptance criteria.

	6) Do design engineers really know what characteristics they need in
concrete?
	Not generally.  They just know they get chewed out when the wheels
fall off.

	7) Any other backlash, rant or intelligent discourse you have to
offer.
	Get the Bureau of Reclamation and others to offer training to
engineers, suppliers (ready mix, admixtures, aggregate, pumpers, and
finishers).  


Regards,
Harold O. Sprague


> -----Original Message-----
> From:	Jay Shilstone [SMTP:j.s(--nospam--at)shilstone.com]
> Sent:	Wednesday, June 25, 2003 10:53 AM
> To:	seaint(--nospam--at)seaint.org
> Subject:	Performance specifications
> 
> 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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