DR1201-LR130823 AUG-22-2013 22:06 P.01
AVA Tex s CMT, Inc.
Construction Materials Testing ( Post-it®Fax Note 7671 Date . #of ■
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GENERAL REPORT
Report Date August 23, 2013 Test Date: August 16, 2013
Client City of Coppell General Report No.: 4
Project Creekview Drive Renovations, 2013 Project No.: 213-0134
Subject Discussion of Proposed Roadway Stabilization Methods
On August 16, 2013, Mr. Richard Gee of Texas CMT, Inc. had two (2) telephone conversations
with representatives of the City of Coppell. The first conversation was with Mr. Larry Davis; The
second conversation was with both Mr. George Marshall and Mr. Davis. A text of stabilization
related costs was sent to Mr. George Marshall later in the day. The purpose was to discuss the
merits of various stabilization methods proposed for the treatment of roadway select fill subgrade
soils. The following items were discussed: ea ff
e5
Lime Stabilization •
1. After lime treatment the subgrade will re ore flexible. rank
2. With the select fill plasticity index of fi (5), the lime treatment may render
subgrade soils to a non-plastic state.
4.
Cement Stabilization -
1. After cement treatment the subgrade will become relatively mo(- •riffle; f any
settlement or slope movement occurs, this may ca e the cement - ed subgrade to
crack, resulting in potential reflective cracks in the concrete surface. `
2. The cement treated select fill subgrade soils will compact more easily than lime treated
subgrade. Cement treated subgrade soils are less susceptible to moisture related leaching
out and loss of improved engineering properties over time.
riv
Cern-Lime Stabilization
1. TXI cem-lime treatment u • •__ . mini r ii of,i - - 'ere- ' cementitious
material and maxim forty-five (45) percent calcium ydroxide (lime).
AUG-22-2013 22:06 P.02
City of Coppell August 23,2013
2. With the utilization of both cement and lime in the cem-lime, the subgrade soils will not
be as brittle compared to straight-cement treated subgrade.
3. The cost of cem-lime is comparable to straight-cement, on the order of '.145 per ton.
As discussed, we estimate about 44 pounds per square yard (about 6 percent) of cem-lime would
be needed to adequately stabilize an eight (8) inch layer of the select fill subgrade soils with a
maximum dry density of 120.9 pounds per cubic foot. This should be followed up with necessary
laboratory testing to verify the estimated amount of cem-lime required for stabilization.
If cement or cem-lime is utilized, we recommend at least the fifth (5th) row of gabions be
completed first. This would include the fifth row 18 inch concrete beam and associated
backfill/gravel layer. Seven (7) day concrete and grout material strengths should be achieved prior
to roadway subgrade treatment. Completion of the fifth (5t11) row of gabions would provide
stabilization to more than one-third of the completed wall height and supply significant toe
protection.
We are in agreement with the Reed Engineering Group geotechnical report's recommendation that
the new roadway and flat work concrete should be performed after the new gabion wall is
constructed and existing walls are stabilized.
cc: Mr. Larry Davis -City of Coppell, Phone: 972-304-3684; via Fax: 972-304-3570
Mr. George Marshall- City of Coppell, Phone: 972-304-3562; via E-mail: gMarshall @coppelltx.gov
•
Texas CMT, Inc. TBPE Firm: F-45 Reviewed 8-,23,13
All letters and reports are for the exclusive use of the client to whom they are addressed. shall n. - .roduced without the full approval of Texas CMT,Inc. e use of our name must receive
our prior written approval. Our letters and reports apply only to the sample tested..,or ob "ed and-e not necessarily indicative of the quantities of apparently identical or similar products.
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Texas CMT,Inc. Project No.213-0134 General Report No.4
Page 2 of 2
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