To echo what Jay said, we do see some quality mix design submittals. That is
not to say that we do not have to hold the supplier's hand to get the right
items together, they seem to have trouble understanding what specifications
or contract documents say.....which is frustrating because really, they are
doing this every day. It is not (or should not be) too hard to get a mix
design together, prepare either trial batches and plot points on a curve for
w/c, or produce historical data for a proposed mix (hey, if it worked last
month why not this one?) to document the delivered strength of that mix, and
to develop a population of tests (and they need to be reminded that a test =
2 cylinders!) to compute standard deviations and then the required average
The problems pop up when a mix that is not in their common type is
specified, i.e. with corrosion inhibitors or really low w/c ratios...or when
testing such as shrinkage, hardened air, or freeze thaw is required...then
they really need to pay closer attention. Unfortunately, we often cannot
give them enough lead time to get this done in a timely fashion.
But Jay is right on about the time issues....a good plant gets gradations
done on a regular basis (unless they are cheap) and they should get
certifications on aggreate for soundness, etc frequently, too. Cement
certifications SHOULD be provided with every bulk cement delivery to the
plant(and in a hot market like today, that should happen a lot) so that
information should be current. Good plants with good quality control should
have good data on cylinder tests that they perform at the plant, and we beg
our clients to add the plant to the distribution for field testing performed
by the owner-engaged testing/inspection entity. We urge suppliers we use to
demand field testing reports from other clients, also. That way they have
good (hopefully) data on which to base their work (notwithstanding the fact
that often field cylinders are poorly made, improperly handled, etc, unless
we ride hard on those field guys)so that it can be easy to get a decent
And as far as historical data is concerned, Jay is right on about
ACI procedures are established so that a population used to establish a
standard deviation is from a sufficient duration so as to eliminate a plant
either getting lucky over a short period of time, or of trying too
hard....likewise, data used to prove that a given mix will meet or exceed
the required (not specified) strength needs to be spread over a specific
period of time.
Personally, I suspect some suppliers use a lot of white-out to fudge dates
and titles on some of their data..........
Richard W. Stone, P.E.
Technical Services/Project Management/Estimating
Concept Design/Engineering/Quality Assurance
Madison Concrete Construction Company
130 Quaker lane
Malvern, PA 19355-2479
Visit our webpage at www.madisonconcrete.com !!!!
From: Jay Shilstone <j.s(--nospam--at)shilstone.com>
Subject: Re: ACI Concrete Submittals
We work with concrete producers every day that produce such submittals. On=
the one hand, more and more engineers are requesting them and, on the=20
other, more and more concrete producers are capable of producing them.
The record that I have heard of is a guy who did submittals to the Corps of=
Engineers. Each mix ran over 1,000 pages, and they had to be submitted in=20
triplicate. The guy bought paper by the pallet. (The counterpoint to that=20
is that one time a Corps rep rejected the submittal because one break in=20
the middle of the 1,000 page submittal was low.)
I see mix submittals all the time. My concerns are:
ACI requires the submittal to include recent test results, which may not=20
properly reflect climatic conditions to be expected during construction.=20
Since strengths usually go down in the summer, I would rather see a=20
submittal with strengths from the previous summer (assuming materials=20
remain the same).
Old aggregate information. Often we get submittals with aggregate gradings=
that are 1-2 years old. In most cases you are lucky to get anything from=20
within the last month.
Also, I would rather see historical timeline charts rather than individual=
numbers. A single test is a snapshot that doesn't tell anything about=20
variability and trends. Tables of numbers don't mean much until you plot=20
them on a graph.
The Shilstone Companies, Inc.
At 11:13 AM 4/27/2005, you wrote:
>How many of you are getting full blown ACI 318, 301, 214 Submittals with=
>Arvel L. Williams, P.E.
>GW=B2 Engineering, Inc.
>4040 N. Stiles
>Oklahoma City, Oklahoma 73105
>Nextel Direct Connect: 142*30*12567
From: admin [mailto:admin(--nospam--at)seausa.org]
Sent: Thursday, April 28, 2005 2:00 AM
Subject: seaint Digest for 27 Apr 2005
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