3 Citizen Group 6-29-15 Email Almer MonluxFrom: "Steve Monlux" <stevemonlux@gmail.com>
To: "Carl Almer" <calmer@eorinc.com>
Cc: "Pam Smith" <nwpsmith@cox-internet.com>, "Jim Shaver"
<jshaver@cmscwd.org>, <steve@kronmiller.us>, "Kristin Tuenge"
<ketuenge@frontiernet.net>, <christine@poplarhillfarm.com>
Subject: Re: Follow Up with Steve Monlux
Date: June 5, 2015 at 1:04:19 AM CDT
Carl: The primary difference between the different materials is not the gradation
itself, it is the clay content that is represented by the plasticity index
requirement. Since there is no plasticity index specified for the MN Class 1 or 5
aggregate, I strongly suspect they are intended to be free draining and are
mostly used as aggregate base under pavements. However, it is quite common
to add clay to gravels that do not have plasticity when crushing new gravel or
fixing existing gravel surfacing in-place on the roadway.
Although the average clay particles are about 30 times smaller than silts, they
are less subject to erosion since they stick together, especially when the small
amount needed as binder in 'bound aggregate' is compacted within the
aggregate-sand mixture.
Also, another primary difference between clay and silt is particle shape - clay
particles are flat and platy, whereas silt particles are primarily round like
sand. This shape is important since water goes through and around the round
silt particles but has a much more arduous path around the smaller flat clay
particles. Clay particles are much less prone to erosion than silt and sand
particles, which is why the bound aggregates containing clay are less prone to
erosion.
I hope this is helpful and that it addresses the questions adequately. Please feel
free to give me a call if discussion is desired.
Thanks!
Steve
406-544-1919
On Thu, Jun 4, 2015 at 9:25 AM, Carl Almer <calmer@eorinc.com> wrote:
Pam,
My question was how does the recommended gradations compare to what is commonly
applied as surface aggregate (in this case MnDOT Class 5) with respect to the highl y
mobile particles.
See attached gradations with Class 5 added on the far right column. Comparison of
gradations reveals that:
Class 5 may have as much as 10% particles greater than ¾-inch
While the range of percent passing for the mid-size particles of Class 5 varies
greatly it is generally specified to have less sand
Class 5 is specified to contain less fines (silts/clays)
The take home for me is that the recommended bound aggregate gradations are not
drastically different than Class 5 and evidence has shown that all of the Class 5, larger
particles included, have been mobile in the past and found their way into the adjacent
waters.
Carl K. Almer
EOR: water | ecology | community
d: 651.203.6024 o: 651.770.8448
From: Pam Smith [mailto:nwpsmith@cox-internet.com] Sent: Wednesday,
June 03, 2015 4:28 PM To: Carl Almer Cc: Jim Shaver; steve@kronmiller.us;
Kristin Tuenge; christine@poplarhillfarm.com; stevemonlux@gmail.com
Subject: Follow Up with Steve Monlux
Hi Carl,
As a follow up to our meeting on Monday, I know that I had offered to relay a question to
Steve Monlux, but I don’t believe that I can do your question justice. I’ve thought about
the issue you raised regarding potential fines and sediment if the bound aggregate
surface does not perform as anticipated, but I’m really not sure how best to word the
question (or even if I understand exactly what you were asking,) particularly because
you referenced a specific band on the gradation chart.
Would you mind communicating your question directly to Steve Monlux (he is cc’d on
this email.) I know that he would be more than happy to answer any questions.
Thank you,
Pam Smith
651-433-5859