ST8201-CN 881122TICKLER FROM: RUSSE .L )OYLE, CITY ENGINEER
DATE SENT: 1}"22-~ ~RESPONSE DUE: ~ .ATEOF[SSUANCE:
ACTION RE QUE S TgD
READ AND COMMENT F Y I
X' FOR YOUR APPROVAL NOTE & FILE
NOTE & REPLY NOTE & RETURN
SET UP APPOINTMENT TO REVIEW ATTACHED
PLEASE TAKE CHARGE OF THIS
WNER's Project No
NGINEER: Ginn, Inc.
17103 Preston Rd., Suite
L.B. 118
tke Rd. Dallas Texas, 75248
NGINEER sPr~ectNo. ,7-378
PREPARE RESPONSE FOR MY SIGNATURE
Iq, gSZ, oOm
wrzu
RESPONSE
,>
CHANGE IN CONTRACT PRICE:
Original Contract Price
$ 5,362,580.00
Previous Change Orders No. N/A to No. N/A
$ N/A
Contract Price prior to this Change Order
3,362,580.0r)
$
Net Increase (decrease) of this Change Order
$ approx. ($7,624.10)
Contract Price with all approved Change Orders
5,554,955.90
$
umenls.
'/TON for Lime Slurry, Ty. A, 5%, 22.5#/SY
tment, mat. in place, for L/me Treatment,
em 260).
duction in Estimated Contract Amotmt of
ect which will be e¢~al to that which was
cy Co. letter oF October 8, 1988 to CiTm, Inc.
Hau.]es & Associates, Inc. October 17, ~988
to GiDn, Inc,
CHANGE IN CONTRACT TIME:
Original Contract Time
Net change from previous Change Orders
0
days
Contract lime Prior to this Change Order
565
Net Increase (decrease) of this Change Order
0
Contract Time with all approved Change Orders
RECOMMENDED: APPROVED:
by ;, ' ...... by
EJCDC No. 1910-8-B (1983 Edition)
APPROVED:
/
(Instructions on reverse side)
CHANGE ORDER
PROJECT: Denton Tap Road Improvements DATE OF ISSUANCE:
from Belt Line Road to Sandy Lake Road
OWNER: City of Coppell
P.O. Box 478
(Name,
Address) Coppell, Texas 75019
CONTRACTOR:
CONTRACT FOR:
L.H. Lacy Co. OWNER's Project No.
P.O. Box 541297
Dallas, Texas 75354 ENGINEER: Ginn, Inc.
1710.3 Preston Rd., Suite 100
· Denton Tap Road Improvements L.B. 118
from Belt Line Rd. to Sandy Lake Rd.. Dallas, Texas, 75248
ENGINEER s Project No J-378
You are directed to make the following changes in the Contract Documents.
D~scription: Substitute Portland Cement at $S0.00/TON for Lime Slurry, Ty. A, 5%, 22.5#/SY
at $61.00/TON (Pay Item 264); and Cement Treatment, mat. in place, for Li~e Treatment,
mat. in place at the same unit prices (Pay Item 260).
Pu~oseorChangeOrdcr: To achieve an estimated reduction in Estimated Contract A~ount of
$7,624.10, while providing a constructed project which will be equal to that which was
originally specified.
Attachments: (List documents supporting change) 1. L.H. Lacy CO. letter o£ October 8, 1988 to Ginn, Inc.
2. ~lohn H. Ha~es ~.Associates, Inc. October 17, 1988
letter to blnn. Inc.
CHANGE IN CONTRACT PRICE:
Original Contract Price
$ 3,362,580.00
Previous Change Orders No.
$ N/A
CHANGE IN CONTRACT TIME:
Original Contract Time
365
N/A to No. N/A
Net change from previous Change Orders
0
days
Contract Price prior to this Change Order
3,362,580.00
$.
Net Increase (decrease) of this Change Order
$. approx. ($7,624.10)
Contract Price with all approved Change Orders
3,354,955.90
$.
Contract Time Prior to this Change Order
365
Net Increase (decrease) of this Change Order
0
days
Contract Time with all approved Change Orders
RECOMMENDED: APPROVED:
b ~//' by
Y /[ ~bT' E~im~r
EJCDC No. 1910-8-B (198~ Edition)
APPROVED:
Prepared by the Engineers' Joint Contract Documents Committee and endorsed by ~ Associated General Contractors of America.
(Instructions on reverse side)
CHANGE ORDER
PROJECT:
OWNER:
(Name.
Address)
Denton Tap Road Improvements DATE OF ISSUANCE:
from Sandy Lake Road to Denton Creek
City of Coppell
P.O. Box 478
Coppell, TX 75019
CONTRACTOR: L.H. Lacy Co. OWNER's Project No.
10888 Shady Trail
Dallas, TX 75554-1297 ENGINEER: Ginn, Inc,
17103 Preston Road, Suite 100
CONTRACT FOR: 'Denton Tap Road Improvements Dallas, TX 75248
from Sandy Lake Road to Denton Creek
ENGINEER's Project No. J379
You are directed to make the following changes in the Contract Documents.
Description: Substitute Portland Cement at $50.00/TON for Lime Slurry, Ty A, 5%, 22.5 #/SY
at $67.00/TON and Lime Slurry TY A, $%, 34 #/SY (9" thick) at $63.00/TON (Pay Items 264
and 264.1); and Ce~nt Treatment, mt. in place for Lime Treament, mat. in place at the
Purpose ofChange Order: sarae unit prices, (Pay Item 260)
To achieve a reduction in estimated Contract Amount of approximately 36,808.00 while
providing a constructed project which will be equal to that which was originally specified.
Attachments: (LJst documents supporting change) 1. L.H. Lacy Co. letter of October 8, 1988 to Ginn, Inc.
2. John H. Haynes & Assoc., Inc. letter of Oct. 17, 1988
CHANGE IN CONTRACT PRICE:
Original Contract Price
$ 1.789.363.03
Previous Change Orders No, N/A to No.
$
Contract Price prior to this Change Order
$ 1,789,363.03
Net Increase (decrease) of this Change Order
$ approx. ($6,808.00)
Contract Price with all approved Change Orders
$ 1,782,555.03
CHANGE IN CONTRACT TIME:
Original Contract Time
365
Net change from previous Change Orders
0
days
Contract Time Prior to this Change Order
365
Net Increase (decrease) of this Change Order
0
Contract Time with all approved Change Orders
365
RECOMMENDED: APPROVED:
,.,
by ~ by
EJCDC No. 1910-8-B (1983 Edition)
Owner
APPROVED:
GINN, INC.
November 22~ 1988
Mr. Russell R. Doyle,
City Engineer
City of Coppell
P.O. Box 478
Coppell, Texas 75019
Re: Denton Tap Road Improvements from Belt Line Road to Sandy
Lake Road; and from Sandy Lake Road to Denton Creek.
Dear Mr. Doyle:
This letter is a follow-up to my November 16, 1988 letter and
your November 18, 1988 response concerning the proposed Change
Order No. i to both projects for the replacement of Lime with
Cement for subgrade stabilization. I am enclosing a copy of John
H. Haynes and Associates, Inc. Laboratory Report No. 18, dated
November 4, 1988, which states the conditions under which the
Cement Stabilization will be acceptable on this project. In our
discussions with the Contractor, L. H. Lacy Co., they have agreed
to abide by the John H. Haynes and Associates Inc.
recommendations and to apply the additional cement required near
Station 91+00 to reduce the Plasticity Index to 12 or less, at
no additional cost to that proposed for 5% treatment.
Since this item has been reviewed and approved by our
Geotechnical Engineer, and we have previously informed you of the
potential cost savings of approximately $ 14,072.10 associated
therewith, we feel that it is in the best interest of the City of
Coppell to approve the proposed Change Orders and allow the
Contractor to proceed at once with his subgrade preparation.
Please call me if you have any questions.
Sincerely,
John C. Karlsruher, P.E.
Project Engineer
enclosures
cc:
Alan D. Ratliff, city Manager
Frank Trando, Deputy City Manager
H. Wayne Ginn, P.E.
David M. Snyder, P.E., L. H. Lacy Co.
Randy Fleming
J378/379
17103 Preston Road ® Suite 100 · LB 118 · Dallas, Texas 75248 · Phone 214/248-4900
JOHN H. HAYNES & ASSOCIATES. INCOF~POFIATED
Geotechnicsl Engineers
Novcmbcr 4, 1988
L. 11. Lacy Company
10888 Shady Trail
P. O. Box 541297
Dallas, Texas 75354-1297
Attention: Mr. David M. Snydcr, P.E.
Re:
Cement Stabilization Tests
Denton Tap Road Improvements
Coppcll, Texas
Job No. 3198(b)
Report No. 18
Gentlemen:
As requested, wc have checked thc roadway subgradc along thc referenced
alignment to locate representative clay samples with high Liquid Limits in Ibc
range of about 48 to 56. Two samples were obtained and tested to evaluate Ihcir PI
reduction with thc usc of cement. The results of these studies arc shown on Plate
No. 1. It was found that thc dark gray clay sample having an LL of 47.5 was
effectively stabilized with 5% cement addition having a reduction in PI to 10.9.
llowever, in thc case of thc sample with an LL of 55.8, 5% cement only reduced Iht
PI to 13.3 whereas 7% cement reduced thc PI to 10.7. With thc exception of this
latler sample obtained at Station 91+00, all other areas of subgrade checked
appeared to have lower plasticity than thc other sample tested.
Therefore, it is our opinion that 5% cement can be substituted for 5% lime as
requested by thc contractor in all areas with equal reduction in PI to below 12 with
Ibc exception 'of thc area around Station 91+00. In this area (and probably up and
down slalion maybe I00'), it is recommended that thc cement factor be raised Io 7%
for adequate PI reduction. The actual extent of the area underlain by the higher
plastic clay (identified as light gray, dark gray and tan CH clay) should be
identified on the ground by our engineering technician and marked for the
higher concentration if cement is substituted for the specified lime material.
Thc compaction specification that L. H. Lacy suggested to usc for Iht cement
stabilization work (COG Spec Item 4.9) indicates thc usc of thc THD lI3-E method. In
order to reduce costs, it is our opinion that a substitution could be made whereby
thc Modified Proctor Method (ASTM D-1557) could be used and a minimum
reqnirement of 95% Modified compaction is required. It is bclleved that very lillle
difference in dcnsily will occur if this substitution is made and 95% compaction is
still required.
~4:~4 SCUCZ Drive · F~.O. Box 3541~1 * Dallas, Texas 75~35 * (214) 350-5600
JOHN H. HAYNES & ASSOCIATES. INC.
Geotechnical Engineers
(]inn, Inc. - 2 -
November 4, 1988
If we can be of further help, please let us know.
Yours very truly,
JllH/jeh
(2 copies submiued)
cc: Mr. Randy Fleming (1 copy)
Ginn, Inc.
JOHN H. HAYNES & ASSOCIATES, INC.
Denton Tap Road Improvements
Station
91+00, Rt.
140+00, Rt.
Coppell, Texas
Atterber9 Limit Tests on Subgrade Soils
DescriptioA
Light gray, dark
gray and tan clay
with trace sand and
gravel
% Liquid
Cement ~
Plastic
Limit(%)
18.9
Dark gray clay with
trace sand
Plasticity
Index(PI)
36.9
5 43.5 30.2 13.3
7 43.7 33.0 10.7
- 47.5 16.4 31.1
5 41.3 30.4 10.9
HANDWRITTEN MEMORANDUM
TO: ~JdH~V FZ~Z~£~5~ FROM:
SUBJECT: C/"]'~/L~ ~ ~F K~
GINN, INC.
CONSULTING ENGINEERS
November 16, 1988
Mr. Russell R. Doyle, P.E.'
City Engineer
City of Coppell
P.O. Box 478
Coppell, Texas 75019 i
Re: Denton Tap Road Improvements from Belt Line Road to Sandy
Lake Road; and from Sandy Lake Road to Denton Creek.
Dear Mr. Doyle:
I am transmitting one copy each of Change Order No. i for each
project for approval by the City Manager. These Change Orders
cover the use of Cement for subgrade stabilization in lieu of the
Lime which was originally specified. The end result of approval
of these Change Orders will be that a net savings of
approximately $14,072.10 will be realized by the City on the two
projects, while achieving a finished product which is equal to
that originally specified. The Change Orders have been executed
by both Ginn, Inc. and L. H. Lacy Co., and may be executed by the
City Manager without Council action since each is a reduction in
Estimated Contract Amount, and neither exceeds a change of more
than $ 10,000.00.
For your review we have attached supporting documentation upon
which our recommendation for approval of the Change Orders is
based. Time is of the essence, since the Contractor intends to
begin stabilization within the next couple of weeks and must have
a definite decision within the next few days in order to avoid
delays in completion of this project. I apologize for the short
notice, but we have been holding this item pending the
Contractor's receipt of test reports from his laboratory
confirming their verbal affirmation that the proposed subgrade
treatment will be acceptable. The report has just been received,
and the Contractor has asked us to proceed with processing the
Change Orders. As we had verbally been assured, the proposed
Cement Stabilization is acceptable, and therefore we recommend
proceeding with approval of Change Order No. i for each project
at this time.
Page 1 of 2
17103Pr~tonRoad ® Sui~lffi · LBII8 · D~lm, Texas75248 · Phone214/2484900
If acceptable to the City Manager, please have him execute the
original Change Orders and return two copies: one for issuance
to the Contractor; the other for our files. You should file the
Original Change Orders with your Original Contract Documents.
Please call me if you have any questions.
Sincerely,
/
· Ohn C. Karlsruher, P.E.
Project Engineer
enclosures
cc:
Alan D. Ratliff, City Manager
Frank Trando, Deputy City Manager
H. Wayne Ginn, P.E.
David M. Snyder, P.E., L. H. Lacy Co.
Randy Fleming
J378/379 (a:dtcemco.)
Page 2 of 2
JOHN H. HAYNES & ASSOCIATES, INOOFIPOFIA]
Geotechnical Engineers
October 17, 1988
Ginn, Inc.
17103 Preston Road, Suite 100, LB 118
Dallas, Texas 75248
Attention: Mr. John Karlsruher, P.E.
Re:
Cement Stabilization Substitution
Denton Tap Road Improvements
Coppell, Texas
.lob No. 3198(b)
Gentlemen:
In accordance with your letter request of October 12, 1988, wc have reviewed L.
H. Lacy's request for a substitution of 5% cement for thc specified 5% lime for
subgradc stabilization on this project with the change in procedural specifications to
thc North Central Council of Government Standard Specification Item 4.9.
We believe this substitution would be acceptable provided that it is
demonstrated that 5% cement will reduce thc PI of gl] thc subgradc soils along tile
project to not greater than 12. In our original gcotcchnical reports, wc identified
some number of plastic clays along thc alignment which had Liquid Limits of 50 to 58
and Pl's of 27 to 34. In order to prove that 5% cement is adequate, we suggest that thc
subgradc bc checked and at least two samples of untreated clay be obtained for
laboratory tests that have a Liquid Limit grcatcr than 50. Thc untreated PI of these
clays should bc on thc order of 30 to 35 and this should be proved by laboratory test.
These plastic clay samples should then bc treated with 5% cement and it should be
demonstrated that this is sufficient to reduce tile PI to not more than 12. If this is not
possible, additional cement should be added until this PI reduction is achieved. All
areas should then bc uniformly treated with at least 5% cement or more if it is found
that a greater cement factor is required to stabilize these plastic clay soils.
It should be pointed out that COG Spec. Item 4.9 requires compaction to be
controlled by Test Method THD l13-E. The cost of this 24 hour Modified Proctor test is
2424 SCuez Orive · P.O. Box 35481 · Dallas, Texas 75235 · (214) 350-5600
JOHN H. HAYNES & A55OCIATES, INC.
Geotechnical Engineers
Oinn, Inc. - 2 -
August 23, 1988
higher than thc 24 hour Standard Proctor test ($200 vs. $140) so a slight difference in
cost will be incurred.
If you have any questions concerning this report, please let us know.
Yours very truly,
JHll/jeh
JOHN 11. ItAYNES & ASSOCIATES, INC.
October 12, 1988
Mr. John H. Haynes, P.E.
John H. Haynes & Associates,
2424 Stutz Drive
P.O. Box 35481
Dallas, Texas 75235
Re: Denton Tap Road Improvements, Coppell, Tx.
Dear Mr. Haynes:
I am enclosing a copy of a letter from L. H. Lacy Company which
is requesting that Cement Stabilization be used for subgrade
treatment in lieu of Lime Stabilization as specified in your
geotechnical investigations and our design for the projects. If
Cement Stabilization can be used on this project, there may be a
considerable savings in both construction time and cost to the
City of Coppell. I would like for you to review and evaluate L.
H. Lacy Company's request. In our previous conversations
regarding this subject you mentioned that in order to evaluate a
request such as this, some information indicating the rates of
application, thickness, and acceptance criteria should be
included. In reading the attached letter it is not apparent what
the acceptance criteria should be, but the rates of application
and thickness proposed appear to be the same as that proposed for
the Lime Stabilization. If you need the results of tests, such
as Ph/PI, Proctors and etc. to evaluate this request, please
respond accordingly.
In order to justify his request the Contractor must pay for and
provide us with any test data or design data which will
adequately convince you that what they are proposing will result
in a finished product equal to or better than that originally
specified. Please call me if you have any questions.
Sincerely, /
Project Engineer
JCK/jk
enclosures
cc: H. Wayne Ginn, P.E.
David M. Snyder, P.E. - L.
Randy Fleming
H. Lacy Co.
1710~ I~c',h~ I~:;Id · SuiIc ]()() ii I1~ I I~ · I);dl:~s,'fcx;Is 7S243 · I'h~nc 214/243-491)0
T T ·
GINN, IN(.
October 13, 1988
Mr. David M. Snyder, P.E.
L.H. Lacy Company
10888 Shady Trail
P.O. Box 541297
Dallas, Texas 75354-1297
Re:
Denton Tap Road Improvements from Belt Line Road to Sandy
Lake Road and from Sandy Lake Road to Denton Creek, Coppell,
Texas.
Dear Mr. Snyder:
In response to your letter of October 8, 1988, concerning the use
of Cement Stabilization in lieu of Lime Stabilization for
subgrade treatment for the above mentioned projects, we have
submitted the information you furnished us to John H. Haynes and
Associates, Inc. for their review and comment. A copy of the
letter we sent to John H. Haynes is enclosed for your use.
We will await the comments from John H. Haynes and Associates,
Inc. before giving further consideration to your proposal. In
the meantime if more information supporting your request
develops, please feel free to forward it to us. Please call me
if you have any questions.
Sincerely,
~,~m~ru~6F,
Project Engineer
JCK/jk
cc: H. Wayne Ginn,
Randy Fleming
P.E.
1'7103 I'lcsh)n I~tl;id · Suit(' 10(} · I,t{ I1,~ · I):,ll;ts, ~icx;Is 7524~ · I'hlmc
PRO.JEEC IS ;;:I-eOM tilEL t' LiNE I0 I)ENICIN L~REEK.
IHE L.. H. I.ACY CO. WOULD LIKE TO FORMALIZE IT'S REQUEST FOR ]'HE FOLLOWING
ALTEFCNATiVE METHOD OF SUBGRAI)E STABILIZATION ON BOTH OF'
PROJECTS:
THE A~dOVE REFERRENCED
1)
lA)
SANDY LAKE TO DENTON CREEK
PROJECI' (379)
ITEM 264 - LIME, 168 TON TO ITEM 264 - CEMENT, 168 'tON
I"FEM 2~4.1 '- LIME (9">,. 5c)4 TON TO ITEM ~64.1 ~ -- CEMEN'I~ 304 TON
BELT LINE ['0 SANDY LAKE
PROJECT (378)
ITEM 264 -- LIME.', 6915. 1 TON FO ITEM 264 - CEMENF~ b95. 1 TON
THE AL.T'EF~NATE METHOD AND SUBSEQUENT PRICE REDUCTION ARE PREDICATED ON 'F'Hli
F OL/.LIW I NI3.
1)
;-~LL WORK TO BE DONE IN ACCORDANCE WITH THE ATTACHED NORTH TEXAS COUNCIL
OF GOVERNMENT STANDARD SPECIFICATIONS FOR PUBLIC WORKS CONSTRUCI'IOI~.
( II'EM 4.9)
2> ~ ONE TO ONE (1 TO 1) SUBSTITU[iON OF CEMENT FOR LIME (FAS REFLECTED
ABOVE).
I'HE L. H. LACY COMPANY PROPOSES THE FOLLOWING PRICE REDUCTIONS iN CONSID-
ERATION QF' THE F'ROPOSAI.. AS IT IS S'IA'I'ED iN 'IHIS LEI']'ER, ANY CHANGE IN METHOD
OR QUANIlTIES FROM '[HOSE PROF'OSED WILL REQUIRE A RESPONSE FROM L. H. LACY CO.
L. H. Lacy Company ~ i; 10888 Shady Trail
General Contractors z~'"~'-~--' ~*~ P.O. Box 541297
214/357-0146 "Qua~,y Conslruction for over 65 Years'* Dallas, Texas 75354-1297
F1N;'~L AfiREEiI"II.':I',II' CAN DJ': F,:[~iACHICD:
SANDY L.tI~,~!.C [O DL:.'IXI[[}N CREEt::~
1) I-IEH 76~I - [:[]'IEI',I'I, 1~,1:1 'ION @ ~LSC .' /'r£]N (I-'IFi'Y DCILLF'd':.:~,S P[:F.~ TON)
ll-~) I I[~H 26Zl. ] - I:~l'll:.lq'l (9"), .".,(lq IUN ;~) '$51).CH-'J/]UN (I='.[F-I'Y DEII_.LltI',:~ 1'~12:1-( ]"ON)
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IN ADDll'J(]lq ]{J THE [:CISI L]AV1NGS F:[JIR 'I"HE CITY 0F COF'PELL IN SUPPLYINb lin
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[:DNSJ [)[~R ]'t1[~ '1 IMEI_.Y NA'FUI~I~ I]F IIII2JSIZ PRO~E[:TS~ 'iH[: I:~I~VI]f:(AB_E TYF, E~ OF THE
I_.. H. LACY"S PRLLV]:OUS SUCCESGES WI'IH fiIMlLt~R [:EME:NF-I'F(EATED SUE~GRADE Al_T--
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F' 1 LE
ITEM 4.9.~. 283
tance by the owNsa. Repairs are to be made in a manner which shall
insure restoration of a uniform surface. Durability of the part required
shall be measured in its final position and the volume computed in cubic
yards (Ma) by the method of average end area.
Soil-asphalt course shall be measured by the square yard (Mz) of cur-
face area of completed and accepted work based on the width of the
soil-asphalt course as shown on the plans, or as established by the
owsss. Asphaltic material of the type and grade shown on the plans
shall be measured in gallons (liters) at the applied tempor~ture at the
point of application on the road.
Work performed and materials furnished as prescribed and measured
by this item shall be paid for at the unit prices bid for soil-asphalt
course and additional soil, which prices shall be full compensation for
cleaning the roadbed or the surface of the previously completed base
course; for furnishing all materials; for loosening excavating, loa.di.ng,
hauling and delivering additional soil on the road; for loosening,
and pulverizing of the soil; for shaping, sprinkling and compacting
subgrade; for all processing, mixing, drying, incorporation of asphaltic
material, aerating and drying, spreading, sprinkling, shaping, compact-
ing, and finishing; for maintaining under traffic; and for all manipala.
tions, labor, equipment, fuels, tools and incidentals necessary to com-
plete the work except as hereinafter provided.
Asphaltic material measured as provided in this item shall be paid for
at the unit price bid for asphaltic material, which price shall be
compensation for furnishing the material; for ail freight involved; for all
unloading, storing, heating, hauling and applying on the read; and for
all labor, equipment, fuels, tools and incidentals necessary to complete
work.
ITEM 4.9. PORTLAND CEMENT MODIFICATION OF
SUBGRADE SOILS
4.9.1. DESCRIPTION: This item shall consist of the treating the sub-
grade soils by pulverizing, addition of portland cement and water,
mixing and compacting the mixture to the required density. This item
applies to natural ground or embankment encountered in the con-
strnction. The cement-modified soil layer shall be constructed as
specified herein and in conformity with the typical sections, lines and
grades as shown on the plans or as established by the ows~e.
4.9.2, MATERIALS:
(a) Portland Cement. Cement shall conform to the requirements of
Item 2.2.1., "Cement."
(b) Water. Water shall conform to the requirements of Item 2.2.4,
"Water."
(c) Soil. The soft shall consist of approved soft, free from vegetation
or other objectionable matter. It may be either the material encountered
in the existing section, material secured from approved sources shown
on the plans or az designated by the owsza, or a combination of existing
and additional soil from approved sources, as shown on the plans, or as
directed by the OWNEa.
4.9.3. EQUIPMEHT: A]~ equipment necessary to properly prosecute,
perform and complete the work within the contract time, shall be on the
project and shall be approved by the
fore the CONr~croa shall be permitted to begin construction operations
on which the equipment is to be used.
The cement-medified soil layer may be constructed with any machine
or combination of machines and auxiliary equipment that shall produce
the results meeting the requirements for soil puiver~ation, cement ap-
plication, water application, mixing, incorporation of materials, compac-
tion, and finishing as specified herein. The cosrRAcroa shall at all times
provide sufficient equipment to enable continuous performance of the
work and its completion in the required number of working days.
4.9.4. CONSTRUCTION METHODS:
(a) General. The primary requirement of this specification is to
secure a complete course of treated subgrade material containing a
uniform portland cement mixture, free from loose or segregated areas,
of uniform density and moisture content, well bound and compacted for
its full depth with a smooth surface suitable for placing additional sub-
base, baze or surface courses. It shall bo the responsibility of the
coN?eAcroe to regulate the sequence of his work to process a sufficient
quantity of material so az to provide full depth az shown on plans, to use
the proper amount of portland cement, maintain the work and to rework
the courses as necessary to meet the foregoing requirements.
Before other construction operations are begun, the roadbed shall
be graded and shaped az required to construct the portland cement
modified subgrsde layer in conformance with the lines, grades, thickness
and typical cross sections shown on the plans. Unsuitable soil or material
shall be removed and replaced with acceptable soil. The subgrade shall
be firm and able to support without displacement the construction equip-
ment and the compaction hereinafter specified. Sof~ or yielding subgrade
shall bo corrected and made stable before construction proceeds.
(b) Application of Cement. Portland cement shall bo spread uni-
formly by an approved dry or slurry method on the soil at the rate
specified on the plans or az determined by preliminary laboratory tests.
If a bulk cement spreader is used, it shall bo positioned by string lines or
other approved method during spreading to insure a uniform distribu-
tion of cement. Cement shall bo applied only to such an area that all the
operations can be continuous and completed in one operation.
The percentage of moisture in the subgrade soil at the time of
cement application shall not exceed the quantity that shall permit
uniform and intimate mixture of soil and cement during dry-mixing oper-
ations; and it shall not exceed the specified optimum moisture content
for the soil and cement mixture.
No equipment, except that used in the spreading and mixing, shall
be allowed to pass over the freshly spread cement until it is mixed with
the soil.
AUGUST
(c) Mixing and Processing. The mixing procedure shall be the same
for "Dry Placing" or "Slurry Placing" as described heroin. The material
and cement shall be thoroughly mixed by approved road mixers or other
approved equipment and the mixing shall continue until, in the opinion of
the Engineer, a homogeneous, friable mixturo of materiai and cement is
obtained, free from all clods or lumps. Materials containing plastic clays
or other material which will not readily mix with cement shall be mixed
as thoroughly as possible at the time of the cement application and
brought to the proper moisture content. The material shall be kept moist
as directed by the Engineer.
The esment-sell mixture shall meet the following gradation require-
ments when tested dry by laboratory sieves:
Minimum Passing 1" Sieve ........................... 100%
Minimum Passing i/~ Sieve .......................... 70%
Minimum Passing No. 4 Sieve ............. ;~ ....... 45%
(d) Compaction. Compaction shall begin immediately after final mix-
lng. The material shall be compacted to 95% of the maximum density, as
established, and in accordance with Test Method Tex I13~E. It shall be
aerated or wetted as necessary to provide optimum moisture. Moisturo
tolerances shall be as described below.
Prior to the beginning of compaction, the mixture shall be in a loose
condition for its full depth. Compaction shall begin at the bottom
and shall continue until the entire depth of the mixture is uniformly
compacted.
Description Density, Percent Moisture Percent
For cement treated Not less than 95, Within 2.5 of
subgrade that will except when shown optimum unless
receive subsequent otherwise on the otherwise shown
courses, plans, on the plans.
In-Place Density tests shall be as outlined in Test Method Tex 114-E
or Test Method Tex I15-E. In-Place Density tests shall be performed at
the rate of one per 300 linear feet of paving for two (2) lanes. The suite-
bility of the stabilization shall be confirmed by Atterberg Limit testing
at the rate of one test per 2,500 cubic yards of processed material.
In addition to the requirements specified for density, the full depth
of the material shown on the plans shall be compacted to the extent
necessary to remain firm and stable under construction equipment.
After each section is completed, tests as nece~ary will be made by the
Engineer. If the material fails to meet the density reqniroments, it shall
be reworked as necessary to meet these requirements. Throughout this
entire operation the shape of the course shall be maintained by blading,
and the surface upon completion shall be smooth and in conformity with
the typical section shown on the plans and to the established lines and
grades. Should the material due to any reason or eanse, lose the stahil-
ity, density and finish before the next course is placed or the work is
accepted, it shall be recompacted and refinished at the sole expanse of
the CONTRACTOR.
(e) Finishing and Preparation for Surfacing. ARer the final layer or
course of the esment-medLqed subgrade has been compacted, it shall be
brought to the required lines and grades in accordance with the typical
sections. The completed section shall then be finished by rolling as di-
rected with a pneumatic tiro or other suitable miler sufficiently light to
provent hair cracking. Preparation for final surfacing may begin hn-
mediately.
4.9.5. MAINTENANCE: The Co~rRAc~Oa shall be required, within the
limits of his contract, to maintain the cement-medified soil in good condi-
tion from the time he first starts work until all work shall have been
completed. Maintenance shall include immediate repairs of any defect
that may occur after the cement is applied. Such maintenance work shall
be done by the conTaAcToe at his own expense and repeated as often as
necessary to keep the area continuously intact. Repairs aro to be made
in such a manner as to insuro rostoration of a uniform surface for the full
depth of treatment. Any low area shall be remedied by replacing the
material for the full depth of troatment rather than adding a thin layer of
stabilized material to the completed work.
4.9.6. MEASUREMENT AND PAYMENT: This work shall be measurod
by the square yard (Mz) of completed and accepted cement-modified
soil. Measurement for cement shall be by the ton, 2,000 pounds (900 kg)
of dry weight, as determined by certified weight tickets. No allowance
shall be made for any materials used or work done outside the limits as
established by the owssa. The work performed and material furnished
as proscribed by this item and measured as provided in this item shall be
paid for at the unit price bid for cement-modified soil, which price shall
be full compensation for pulverizing the soil material; for handling; haul-
ing and spreading the dry or slurry cement mixture; for mixing the
cement with the pulverized soil; furnishing, hauling and mixing water
with the cement-soil mixturo; sproading and shaping the mixture; com-
pacting the mixture, including all rolling required for this compaction;
surface finishing;, and for all manipulation, labor, equipment, appliances,
tools and incidentals necessary to complete the work and carry out the
maintenance provisions in this specification. Cement material measured
as provided in this item shall be paid for at the unit price bid for cement
material, which price shall be compensation for furnishing the material;
for all freight involved, for all unloading and storing; and for all labor,
equipment, fuels, tools and incidentals necessary to complete the work,
all in accordance with the plans and these specifications.