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NATIONAL BUREAU OF STANDARDS REPORT10 690
QUARTERLY PROGRESS REPORT NO. 1
SEPTEMBER 17 TO DECEMBER 31, 1971
Title of Project
NONMETALLIC COATINGS FOR CONCRETE REINFORCING BARS
Sponsored by
Federal Highway Administration
U.S. DEPARTMENT OF COMMERCE
NATIONAL BUREAU OF STANDARDS
NATIONAL BUREAU OF STANDARDS
The National Bureau of Standards 1 was established by an act of Congress March 3, 1901. Today,
in addition to serving as the Nation’s central measurement laboratory, the Bureau is a principal
focal point in the Federal Government for assuring maximum application of the physical andengineering sciences to the advancement of technology in industry and commerce. To this endthe Bureau conducts research and provides central national services in four broad program
areas. These are: (1) basic measurements and standards, (2) materials measurements and
standards, (3) technological measurements and standards, and (4) transfer of technology.
The Bureau comprises the Institute for Basic Standards, the Institute for Materials Research, theInstitute for Applied Technology, the Center for Radiation Research, the Center for ComputerSciences and Technology, and the Office for Information Programs.
THE INSTITUTE FOR BASIC STANDARDS provides the central basis within the UnitedStates of a complete and consistent system of physical measurement; coordinates that system with
measurement systems of other nations; and furnishes essential services leading to accurate and
uniform physical measurements throughout the Nation’s scientific community, industry, and com-
merce. The Institute consists of an Office of Measurement Services and the following technicaldivisions:
Applied Mathematics—Electricity—Metrology—Mechanics—Heat—Atomic and Molec-ular Physics—Radio Physics -—Radio Engineering -—Time and Frequency -—Astro-physics -
—
Cryogenics. 2
THE INSTITUTE FOR MATERIALS RESEARCH conducts materials research leading to im-proved methods of measurement standards, and data on the properties of well-characterized
materials needed by industry, commerce, educational institutions, and Government; develops,
produces, and distributes standard reference materials; relates the physical and chemical prop-
erties of materials to their behavior and their interaction with their environments; and provides
advisory and research services to other Government agencies. The Institute consists of an Office
of Standard Reference Materials and the following divisions:
Analytical Chemistry—Polymers—Metallurgy—Inorganic Materials—Physical Chemistry.THE INSTITUTE FOR APPLIED TECHNOLOGY provides technical services to promotethe use of available technology and to facilitate technological innovation in industry and Gov-
ernment; cooperates with public and private organizations in the development of technological
standards, and test methodologies; and provides advisory and research services for Federal, state,
and local government agencies. The Institute consists of the following technical divisions and
offices:
Engineering Standards—Weights and Measures— Invention and Innovation — VehicleSystems Research—Product Evaluation
—
Building Research—Instrument Shops—Meas-urement Engineering—Electronic Technology—Technical Analysis.
THE CENTER FOR RADIATION RESEARCH engages in research, measurement, and ap-plication of radiation to the solution of Bureau mission problems and the problems of other agen-
cies and institutions. The Center consists of the following divisions:
Reactor Radiation—Linac Radiation—Nuclear Radiation—Applied Radiation.THE CENTER FOR COMPUTER SCIENCES AND TECHNOLOGY conducts research andprovides technical services designed to aid Government agencies in the selection, acquisition,
and effective use of automatic data processing equipment; and serves as the principal focus
for the development of Federal standards for automatic data processing equipment, techniques,
and computer languages. The Center consists of the following offices and divisions:
Information Processing Standards—Computer Information— Computer Services— Sys-tems Development—Information Processing Technology.
THE OFFICE FOR INFORMATION PROGRAMS promotes optimum dissemination andaccessibility of scientific information generated within NBS and other agencies of the Federalgovernment; promotes the development of the National Standard Reference Data System and a
system of information analysis centers dealing with the broader aspects of the National Measure-
ment System, and provides appropriate services to ensure that the NBS staff has optimum ac-cessibility to the scientific information of the world. The Office consists of the following
organizational units:
Office of Standard Reference Data—Clearinghouse for Federal Scientific and TechnicalInformation 1—Office of Technical Information and Publications—Library—Office ofPublic Information—Office of International Relations.
1 Headquarters and Laboratories at Gaithersburg, Maryland, unless otherwise noted; mailing address Washington, D.C. 20234.a Located at Boulder, Colorado 80302.;l Located at 5285 Port Royal Road, Springfield, Virginia 22151.
NATIONAL BUREAU OF STANDARDS REPORT
NBS PROJECT
4216442
NBS REPORT
January 24, 1972 10 690
QUARTERLY PROGRESS REPORT NO. 1
SEPTEMBER 17 TO DECEMBER 31, 1971
Title of Project
NONMETALLIC COATINGS FOR CONCRETE REINFORCING BARS
Sponsored by
Federal Highway Administration
U. S. Department of Transportation
Washington, D. C. 20590
i
by
j^VJames R. CliftonRobert G. Mathey
Ramon L. Cilimberg
Building Research Division
Institute for Applied Technology
National Bureau of Standards
Washington, D. C. 20234
IMPORTANT NOTICE
NATIONAL BUREAU OF STAN r
for use within the Government. Bel
and review. For this reason, the pi
whole or in part, is not authorizec
Bureau of Standards, Washington, I
the Report has been specifically pre
Approved for public release by the
director of the National Institute of
Standards and Technology (NIST)
on October 9, 2015
accounting documents intended
>jected to additional evaluation
ting of this Report, either in
ffice of the Director, National
te Government agency for which
es for its own use.
U.S. DEPARTMENT OF COMMERCE
NATIONAL BUREAU OF STANDARDS
m ' I
.
"
e
..
PREFACE
This is the first progress report for the project Nonmetallic
Coatings for Concrete Reinforcing Bars . The period from September 17
to December 31,
1971 is included in this report. Subsequent reports
will be issued on a quarterly basis.
l
I1 _
Quarterly Progress Report No. 1(September 17 to December 31, 1971)
1. Study Identification: Order No. 2-1-0614
Title: Nonmetallic Coatings for Concrete Reinforcing Bars.
2. Date Work Started: 9/17/71
Date of Report: 12/31/71
3. Research Agency: National Bureau of Standards
4. Background
The early deterioration of the concrete of bridge deckings has
become a significant problem during the past decade. The annual cost
of repairing such bridge deckings is about 70 million dollars.
The major portion of the early deterioration of concrete bridge
decks has been attributed to the corrosion of steel reinforcing bars
embedded in the concrete, which causes delamination and subsequent
spalling of the concrete. Normally, reinforcing steel is passive
towards corrosion in a basic environment as provided by concrete. This
passivity, however, is destroyed by the presence of chloride ions and
active corrosion takes place.
Presently, the two mostly used de-icing agents on highways and
bridges are sodium chloride and calcium chloride. These de-icing
agents when dissolved in water are able to penetrate the concrete decks,
thus, leading to corrosion of steel reinforcement and subsequent
cracking and spalling of the concrete. In the past decade, the amounts
of sodium chloride and calcium chloride used as de-icing agents has
increased multi- fold.
1
A reasonable method to prevent the corrosion of the steel reinforcing
bars is by coating them with a barrier-type protective coating. It
is felt that epoxy systems are the most promising coatings for this
application.
5. Objectives
To investigate the feasibility of using epoxy systems to protect
steel reinforcing bars and to select the epoxy systems that provide
the best protection. The selection will be based on physiochemical
testing with consideration given to economics involved in coating and
fabricating of reinforcement.
6. Progress
The work in the first quarter primarily consisted of (1) attaining
an overall view of epoxies, their chemical and physical properties and
the feasibility of using them to protect steel reinforcing bars from
the accelerated corrosive attack caused by chlorides from de-icing
salts used on bridge decking. This was accomplished by a thorough
literature search, discussions with experienced researchers and
contact with epoxy manufacturers, formulators and applicators;
(2) ascertaining what appropriate epoxy systems are commercially
available; (3) the preliminary selection of promising epoxy systems;
(4) consideration of existing methods of test applicable to various
phases of this project and the development of new test methods, when
necessary; (5) investigation of methods and techniques for applying
protective coatings; (6) determining what surface condition of the steel
reinforcing bars is necessary to obtain a sound protective coating.
2
The names and addresses of prospective epoxy manufacturers and
formulators were obtained by consulting the Thomas Register and by
reviews of such journals as Corrosion Abstracts, Corrosion, and
Materials Performance and Protect ion^ and by consulting with members
of the National Bureau of Standards staff and the staffs of other
organizations. The epoxy manufacturers and formulators contacted by
letter, inquiring if they have epoxy coatings applicable to the
present project, are listed in Table 1 along with comments regarding
the nature of their replies and products. Six firms were visited
by the NBS staff assigned to this project and the firms are listed
in Table 2. Twenty of the firms given in Table 1 have replied to
the initial inquiry. Three of those who replied stated that they
had no materials suitable for the protection of steel reinforcing
bars. Five firms, although advertised to handle epoxies, forwarded
only information on non-epoxy systems. Altogether (Tables 1 and 2),
17 firms handling epoxy systems have been receptive to our contacts.
It has been decided to investigate only 100 percent solid
epoxies, which can be either solids or liquids, as solvent containing
coatings are highly susceptible to the formation of holidays
necessitating the application of several coats. Furthermore,
epoxy formulations with coal tars will not be studied since such
formulations performed badly in reinforcing bar pull out tests ^
.
The epoxy floor covering materials do not appear to be very promising
as protective coatings for reinforcing bars. To date 11 firms have
been requested to submit samples for testing. Two samples have
been received and the remaining samples will probably be received
3
during January 1972. It is still possible that other firms,
including some not listed in Tables 1 and 2, may be requested to
submit test samples in the near future.
For the purpose of simulating in-shop applications, the epoxy
manufacturers or formulators that are willing to submit test sample
are being requested to coat a few bars during a later portion
of this project. Reinforcing bars were supplied by NBS to five
of the firms visited for them to apply their coatings. These bars
had different surfaces such as rust, mill scale and sandblasted
surfaces, in order to determine what surface preparations will
be necessary. At least one firm would not agree to application
of their coatings to a surface which had not been sandblasted
or pickled for mill scale and rust removal. The majority of firms
stated that bars should be sandblasted for the best coating
performance with pickling being the minimum surface preparation
that is acceptable.
Other facets of the development of an epoxy system to coat
reinforcing bars that have been considered are: (1) holiday
detection; (2) determination of thickness of coatings; (3)
application methods such as electrostatic spray, conventional
air spray, hydraulic spray, dipping electrodeposition, and fluid
beds; (4) site of application, in-situ or in-shop. Presently,
in-shop application appears to be the most feasible method.
A general work plan-time schedule is presented in Table 3. In
the following quarter's progress report more detailed schedule will
be submitted. It is felt that the current work is progressing
according to schedule.4
7. Problems
A. Casting of Specimens for Pull-Out and Creep Testing
Wooden forms in which specimens for the pull-out and creep
tests will be cast are being designed and will be fabricated at
the National Bureau of Standards. It is felt the specimens should
be cast with concrete having the same properties as that used in
the current corrosion testing being carried out at the Fairbank
Station of the Bureau of Public Roads. We are requesting, therefore,
that the Bureau of Public Roads cast and cure the creep and pull-out
specimens at the Fairbank Station using forms and reinforcing bars
provided by the National Bureau of Standards. Control concrete
cylinders cast along with the creep and pull-out specimens will
be tested at NBS . Concrete proportions and method and time of
mix should be provided to NBS.
B. Procurement and Logistics
As could be anticipated, the procurement of test samples
is a slow process, however, it is hoped that most samples will
be received by the end of January 1972. The logistics involved
in shipping reinforcing bars, having them coated and returned
will probably be time consuming and will be dependent on the
speed of the applicator.
8. Work Planned for the Next Quarter
In the next quarter, the chemical resistance of cured
epoxies, cast as discs, will be investigated in order to eliminate
from further consideration any unacceptable systems. Disc specimens
will be exposed to water, chloride and sulfate ion solutions.
5
aqueous saturated CaCOH)^ solution, steel, and cement paste and
concrete. The permeability of thin films of epoxies to moisture
and chloride ions will also be tested.
Corrosion testing of coated reinforcing bars toward chloride
ions will be commenced. This will include such methods as visual
inspection and electrochemical measurement.
The initial phases of pull-out and creep testing will be
started. This includes the fabrication of specimen forms and
setting-up of test equipment.
Some other aspects to be explored will be the feasibility
of application of epoxy to reinforcing bars in-situ and the degree
of surface preparation necessary for epoxies to adhere well to the
steel reinforcing bars.
9 . Acknowedgment
The contribution of Mr. Hugh F. Beeghly to this project is
appreciated
.
Reference
1. D. G. Moore, D. T, Klodt and R. J. Hensen, Protection of Steel
in Prestressed Concrete Bridges, National Cooperative Highway
Research Program Report 90, 1970.
6
TABLE
1.
Epoxy
Manufacturers
and
Formulators
Contacted
by
Letter
CO
Xcd
00c
00 •ftd J-l•H oo OX i—
l
o 4-14-1
d X•X d0) cd
J-l
CO
X cucd CO
o cdo o
o 5>s4J S-i CO
4-1 £x cdCO X rH CL•nl o CO cu •X CO o X r—1 £ coj-i 4-1 CO x d Q co rX CO X d O •Xcu •r4 OO -X •x d d cd •X o X cd CO CJ ocu T—
1
d o £ o cu d •X o 3 cd cd d dd cd •x d cd o oo cu X d x d o o CO d d •r^•H cj X -x d x fa X •X o cd •X •r-l rX ^ X X - 3 i—1 fa X cu o X X Mw CO d x U X PQ -3 X X d -d cu o
cd •X o 00 d 00 X CJ r\ d rj oCU rX fa •* d 4-4 d x X r\ d co X 3 X> x o cd oo Cd 3 o o - X 3 g O CO X
•r) cd X oo o d O XI X 00 x £ d -Q X iX oCO o cu cd •X *x •X CO 3 cd x cd cd £ co N cu X x CU X p •X £ x -d rX rX X X oX cd x js £ cd £ X x X x cd co o X
43cd
H
cu •
44cd o COo 4-1 • ai•r4 CO •r-l
r-4 X 54 X•|4 ai ctf oCO a o >*44 4-1 cd
O X J3d x
ai cd ai
I—
1
4-1 01CL x co -dg •h a; 4-1cd d dCO cr cr 4-1
cd
d01
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o •o COH 01
44
O
a§
od1-4
cdX4-1
CO
0)
4-1
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4-1
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X ai -Q CO r\01 CO •
d 4-1 00 CO ai I—
1
d d cd d 01 X CL•H 01 •rl r—
1
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>->
dcd
Cl,
goCJ
•H X cd »>> d d •r4 CO
•iH o cd d 44d Q •r4 d 54 O
• cd 44 • o CO o do Cl co cd a >> •r-l 54 d ^ Xd B O 54 d 01 44 d 01 O *r4 o 01M •H o O •r4 o M CO cd o 54 •i4 r-4 54 01
54 cj d 44 Cl -X 54 54 B cd 44 Cd P4 COr\ d 44 CO 54 54 rs 01 o d 01 £ Cd cj CO
5-1 d o 00 d cd O O co X a, cd S cd 54 01d o cd co d 01 r—
1
CJ >-< 44 5-i 00 rH o « cd dcd >-* a- co •r4 p4 o £ O "r-l 01 01 Cl, 01 o da g r! 44 01 12 d 01 CJ 4P X Q 54 44 •r-l aig £ o S cd r\ x) X 0) X s O o d g Ho 01 cj O cj d •r-l S o 00 -r4 44 CJ o 01cj S r\ cj cd 43 5-i T\ d S d d X -d
01 co O 54 r\ p4 X •rH o o 01 CJ 440) r\ d -h 01 44 r-4 cd ,-X o d - p4 44 44 T—
1
54
4-1 O •h d CO CO cd CJ 54 00 o 54 x d 00 •H w d o•r-4 i—4 «H O 0) 54 o O d £ o d Q d r4 cd D-,d cd O hJ d 01 •r4 d >4 •tH 01 cj cd •iH -d g COo 44 43 cd 44 g o 44 rH rH • B X 44 44 00CO 44 54 • r-4 44 0) •H £ cd 00 £ X h4 rH o d co d•H d cd 4-1 01 01 4C d ai o d o -iM • •H Cl O cd •rHPQ P3 CJ CO cj X o CJ W Q £ w rs W C/3 W
• . • # . . , .»' 1
r-4 CM CO m X 1— 00 CT\T—
1
r-4 rH t-4 1-4 1-4 r4 r-4
- 8 -
Gates
Engineering
Division
Products
are
Neoprene
and
Hypalon
and
epoxies.
Have
Wilmington,
Delaware
been
requested
to
submit
sample
and
to
coat
reinforcing
ba
0) 05
> Xcd •HX2 >
oCO 54
CL) CLrHCL oB w 44cd 5-i
CO cu XX 05 CO05 54
. 00 54 03
2 e GO XQ) *H cd-u O GOCO j-i 05 d
o > *HCO 44 cd o
c HJ 54X ’•"* O•«4 05 M-l
3 5-1 • dcr CO *H•H 44 B 05i—i cd a> 54
o 4-»^ O CO 4-1X cdo o CO Oa, u o05 X ex •H O 05 CO05 05 d -u 44 eHO 05 cr CO 05•i-5 54 *p4 X 44B oo i—» 0) CO CO03 < 4-» POPo Po CO 05 COrH X 05 do • O 3 cd 54Cl to Cl cr u cd
05 05 05 X 4Jco > eX *H X 05 i-4•f4 05 •rl E cdr-l O rH • oO 05 O co 4J oCO 54 CO (1) r—
J
i
r—
1
cd Poe-2 a b-5 a • X XO 05 o B (X CL oO 05 o cd CO CLt-4 X H (0 < w
oCM
CO Q Po OPo 4-J Po •r4 d cd •r4 cdd 4J d CO CO cd •r4 4-5 •Hcd 05 cd •H i-4 cd CL. d cd dCL CO CL > kO cd 4-5 E cd u cd2 3 B •H 05 o o o > o d >o 4-J X o Q CO •r4 CO d cd u t-4 CL o t-4a d U o 54 B 05 cd 44 Po 54 •H -X Po
0) cd CO a) 05 d CL O X CO o CO 5m COo B CO o 4-J ”3 X d £ CO d d o •H O d•i4 4-1 CO •H o o •i-l o 05 cd d > pH Po d54 54 cd 54 3 3 s o d O) 05 •H d 054-) cd S 4J X 05 CO d 05 Pm rH Q 3 cd PmO CL a O 25 pH «\ 54 •H CL rH 05 CL05 05 r\ 05 54 rH CO 05 S •r4 r\ •H X S B
i-4 Q X) r—
1
Pm r\ •H •H t-4 03 X > d 0 Xw i-4 w X) s rH 1—
t
r» bO d cd u POCO ai 05 5m o 3 rH • 54 cd 54 X 54
t-4 o •r4 r-4 d O i-4 CL Pm 3 PP 3 pp 54 CO 3cd •r4 144 cd o 44 cd cd cd X O 54 X54 4-» CO 54 o 54 54 0) • Pm CO CO CO X >4 05 CO05 CO 44 05 •H 05 05 d PP 05 4J d o CL 44d cd 4-5 d r-4 4-5 d d • B 44 x 4-> 3 CL 4405 i-4 •>4 05 •H cd 05 •H • 4-J cd •i4 o 3 05 O •r4O Pm Pm o C/3 Ds O s 33 03 X Pm X Q S3 PX Pm
. • • • • s
i—4 CM co LO x r^-C\1 CM CM CM CM CM CM
00CM
9
Kordell
Industries,
Inc.
N.R
Mishawaka,
Indiana
B04
4-4
CO
PdCO
PoXOO-.
04
4-4
ao> ^d 4-i r—
1
o d cdCd CD •HB > dO 1-1 CD T—
1
o o 4J ctfCO cd «-J
CD B pd d CDO *d GO 4-1• d cdcd X •d s
cd GOo *—t o d
O oCO CO dCD CO o CD
i—! *H •rl >O-i X r—< OB o ocd Po dco X CD d
O X OX X Cd a O04 CO CD CD idd 4-1 X •H d *h•H Qd
cd d COo 4J 4-) d•d d o dd o d cd •rl •d do cd CO d d Q o•d rv GO o d id4-1 CO GO d CO o co •dcd GO d •d CD d co id idd d •d d d cd co cd cdO •d d cd d Cd -d •d ua. d d o •d g S dd Cd o s o CDO CO o « 4-1 cdu cd CO r\ CO cd COX 4J 0) r—
1
o •d S CD-X d o > d 4-4 d sCD O CO •d cd d o o4-4 4-1 CD CO Pd cd 1-3 o cdcd 4-4 d CD CO p 4-4d cd d • d 'I*® d CO•d 4-1 •d X) 4J o 4-1 cd o
CO a < CO a CO IS
• •
o•
CNCn| co CO co
OdH
d cdo d •d•d cd d aCO a cd d•d to B > H> 04 o rd
• •d CO u Po ao Q d CO CO •d 04 co d GO a PoM d X 4-4 d d d 0)
•d O 04 •d m CO 04CD Pi IS o r\ O -C 04 X•d d cd o O 4-id X «* Pd •d O £4J d X! .d 04 r o 04CO cd t—
1
X a > X 1 ISd 04 04 rd •d d 4-1 cdO cd o d •d O 04 O £Pd o r—
1
04 .d d 1—1 d 04Pd u PQ Pd Pd Pd O Pd IS
. I •CO 40 XCO co co CO
10
37.
Robray
Industries
Applied
powder
coatings.
Recommends
their
PVC
coating.
Verona,
Pennsylvania
Has
epoxy
system.
Agreed
to
coat
reinforcing
bars.
60 COd i—
t
•H CO4-4 •rl
CO Ph
cu CU CO
4J 4-1 r—
1
cO CO XPh £< •r4 oo Ph a-CM cu CU cu
4J 4JCO CO cO 4-J
CL CO O *60 cO 3 o od CO•h O O cuX • d d d d•r4 CO o *h> U CO CU cuO cO 60 > > CO XU X> d cO cO cuOh •H XL XL CM >
60 4-J o rHd cO P^ >, o
• •r4 O CU CU cu coCO O o rd XL r—1 CO£ 54 4J 4J CL v-4CL) O 60 £ X4_J CM d 4J 4J COco d •f) CO CO CO5>1 *I“I d -d X XCO cu •rl 4-4 4-1 co O
Ph M CLX) X) 4-» a>
X 4-4 -X CU CU do CO d 4-) 4J cu XCL O CO CO co CO cucu o 4-J 4-J 4-J Ph
CO CO 3X cu o u rH o i-H Pd
TABLE
2
Epoxy
Manufacturers,
Formulators,
and
Applicators
Visited
by
NBS
Staff
CO CD
CO G G X GG CO cd •H •HO •H X) X > >«. 4-»P > G O X cdX X cd 4-> • G O 4-1O cd 4-1 CO CL CL COG CO i—
1
c o CD o G•H • o CD G 4-1 « Gi—1 CO X) U cd CO X CL >s
bO G o CD CD XX G 4-1 G (D 4-1 4-1 iHcu x cd cl 4-1 cd rH CO4J X o CD >> O •H Gcd cd a G X G 3: •He o rH O o Xo a 0) 4-1 cd CO G 4-1 G G GX 4-1 O CO CL G • XO cd CO n cd co o XCL CO 44 e u CO C 4H CD CO xG G P > cd • g cd • cdX G CO X rH X CO Cl co G •£ -u G G P CD G B V •H COO G •H cd £3 4-1 •H 4J O x X Xa. x CO £ G cd CO CO G CL CL 0
a) o G O o CD CD E CL 43CO >s G CL O 4-4 o G 4-> bQ cd cd 4-1a) cd CD 4-1 C co G•H X*H «H & 4-1 i—
1
>,X
CD
X & &•HX X & s
CL X o cd i—
1
O O 0 cd co O Ga, o CL 43 •H CL o CL CL O G CL P< rC w £ £ W 4J W G O X W bO
cd
•rH
ccd
> G Ci—
i
CO G cdG G cd >N CL
co G co CL G B X>> G X G g ra o ^ GG C G O G O G cdcd G £ X O G CO t—
i
CL CL G X X G >> ^E Z £ rH cd G G GO « G cd £ G X cd cdo cd «\ Z G G •H CL £
•H G •H £x E £ EG 43 G g G G o «G CL > 4-1 G « 43 Z O G•H X X CO 43 ^ O GG G K G U G #\ X OCL X G P x C X g
cd co 43 x X •H O o x• rH < -
TABLE 3
GENERAL PROJECT SCHEDULE
0->
-
—
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