NATIONAL BUREAU OT STANDARDS REPORT

PROGRESS REPORT

ON

BONDING TO TREATED CONCRETE SURFACES

by

Winthrop C. Wolfe

U. S. DEPARTMENT OF COMMERCE

NATIONAL BUREAU OF STANDARDS

7492

Approved for public release by theDirector of the National Institute of

Standards and Technology (NIST)

on October 9, 2015.

THE NATIONAL BUREAU OF STANDARDS

Functions and Activities

The functions of the National Bureau of Standards are set forth in the Act of Congress, March 3, 1901, as

amended by Congress in Public Law 619, 1950. These include the development and maintenance of the na-tional standards of measurement and the provision of means and methods for making measurements consistent

with these standards; the determination of physical constants and properties of materials; the development of

methods and instruments for testing materials, devices, and structures; advisory services to government agen-

cies on scientific and technical problems; invention and development of devices to serve special needs of the

Government; and the development of standard practices, codes, and specifications. The work includes basic

and applied research, development, engineering, instrumentation, testing, evaluation, calibration services,

and various consultation and information services. Research projects are also performed for other government

agencies when the work relates to and supplements the basic program of the Bureau or when the Bureau’sunique competence is required. The scope of activities is suggested by the listing of divisions and sectionson the inside of the back cover.

Publications

The results of the Bureau’s research are published either in the Bureau’s own series of publications orin the journals of professional and scientific societies. The Bureau itself publishes three periodicals avail-able from the Government Printing Office: The Journal of Research, published in four separate sections,presents complete scientific and technical papers; the Technical News Bulletin presents summary and pre-liminary reports on work in progress; and Basic Radio Propagation Predictions provides data for determining

the best frequencies to use for radio communications throughout the world. There are also five series of non-periodical publications: Monographs, Applied Mathematics Series, Handbooks, Miscellaneous Publications,

and Technical Notes.

A complete listing of the Bureau’s publications can be found in National Bureau of Standards Circular460, Publications of the National Bureau of Standards, 1901 to June 1947 ($1.25), and the Supplement to Na-

tional Bureau of Standards Circular 460, July 1947 to June 1957 ($1.50), and Miscellaneous Publication 240,

July 1957 to June 1960 (Includes Titles of Papers Published in Outside Journals 1950 to 1959) ($2.25); avail-

able from the Superintendent of Documents, Government Printing Office, Washington 25, D. C.

NATIONAL BUREAU OF STANDARDS REPORTNBS PROJECT NBS REPORT

1000-20-10401 25 April 1962 7492

PROGRESS REPORT

ON

BONDING TO TREATED CONCRETE SURFACES

by

A

Winthrop C c Wolfe

Organic Building Materials SectionBuilding Research Division

Sponsored by

Office of the Chief of EngineersDepartment of the Air ForceBureau of Yards and Docks

IMPORTANT NOTICE

NATIONAL BUREAU OF STANDARDS REPORTS are usually preliminary or progress accounting documentsintended for use within the Government. Before material in the reports is formally published it is subjected

to additional evaluation and review. For this reason, the publication, reprinting, reproduction, or open-literature

listing of this Report, either in whole or in part, Is not authorized unless permission is obtained in writing from

the Office of the Director, National Bureau of Standards, Washington 25, D. C. Such permission is not needed,

however, by the Government agency for which the Report has been specifically prepared if that agency wishes

to reproduce additional copies for its own use.

U. S. DEPARTMENT OF COMMERCE

NATIONAL BUREAU OF STANDARDS

PROGRESS REPORT

ON

BONDING TO TREATED CONCRETE SURFACES

1. INTRODUCTION

Concrete floors have been treated with chemical "hardeners" for many years. Certainother treatments are a result of changes in practice in the trade. The mostimportant of these changes is the substitution of membrane curing for the so-called"water cure" for concrete. Another kind of treatment of concrete is essential to acomparatively new type of construction known as lift-slab or tilt-slab.

Proper curing is required for a concrete slab to develop maximum strength and adesirable surface. A concrete floor or wall should be smooth, hard, and free fromcracks or "dusting". If the surface is to be painted or covered with resilientfloor covering, it is essential that paints or adhesives for floor coverings adhereto it. If a concrete floor has been allowed to dry from the surface before it hasbeen properly cured, cracks are likely to develop and the surface may become"dusty". This will interfere with the application of paint or adhesives. Some-times the surface of improperly cured concrete is improved by applying chemical"hardeners". These "hardeners" generally consist of water solutions of magnesiumor zinc fluosilicate, sodium silicate, aluminum sulfate, or zinc sulfate. However,a properly finished and cured concrete slab made from the proper mix will have asatisfactory surface and the use of such "hardeners" will not be necessary.

The standard procedure for curing concrete has been the "water cure" and is simplyto supply water for curing from the outside. This may be done by sprinkling,applying wet burlap, etc., or by "ponding". However, these procedures delay con-struction and require expensive labor. Also, it is desirable to conserve water,especially in arid sections. There is enough water already present in the concretemix to effect curing by hydration of the cement; hense, present day constructionpractice is to seal in this water.

Water may be sealed in by means of waterproof paper, polyethylene film, or someother kind of waterproof sheet material. Another method which is growing inpopularity is the "membrane curing" procedure, whereby a waterproof coating isapplied to the moist concrete. This practice has been known for over twenty yearsand a number of commercial membrane curing agents are available.

In addition to chemical "hardening" and membrane curing, a concrete treatment ofinterest in this study is one essential to lift-slab and tilt-slab construction.This type of construction was devised about twelve years ago to save the expenseof concrete forms. In lift-slab construction, upright steel I-beams are firstset in footings about 30 or U0 feet apart. Special steel "collars" are placedaround these steel columns to support the concrete slabs. The ground slab ispoured in the normal manner and a liquid preparation is spread on the "green"concrete. This preparation acts as a membrane curing agent and also as a "partingagent" or "bond breaker" » After the ground slab has cured a sufficient length of

- 2 -

time, another slab is poured directly over it to serve as the second floor. Thissecond slab is treated in the same manner as the ground slab if other slabs areto be poured over it. In this manner, a multiple sandwich structure of as manyas ten or more slabs is built up. Hydraulic lifting apparatus is connected tothe steel "collars" in the top slab and it is slowly lifted into position to formthe roof. The parting agent enables the separation of the top slab from the onebeneath it. After lifting the slab into place, the steel collars are welded tothe columns. The floor slabs are likewise lifted and welded in place. In tilt-slab construction, concrete slabs for walls are poured on the ground and thenlifted in place. Parting agents are used to separate these from the ground slab. -

2. COMPATIBILITY OF TREATED CONCRETE SURFACES WITH RESILIENT FLOOR COVERINGS

The Asphalt and Vinyl Asbestos Tile Institute has expressed the opinion that failuresin resilient flooring installations on concrete floors have been traced to membranecuring agents used on the floors. The Institute Technical Research Committee metwith the Portland Cement Association in January 1961 to discuss the followingproblems encountered with resilient tile on concrete floors that had been treatedwith curing agents; adherence, oozing, softening of tile, and cupping of rubbertile. There have also been reports suggesting problems with resilient flooringwhich might be due to parting agents. Parting agents are compositions similar tocertain types of curing agents and some preparations are advertised for both pur-poses. It should be realized that it is impossible to base conclusions solely onfield observations. Field inspections should be backed up by laboratory research.

For example, a 4-story building in Rockville was constructed a little over a yearago by the lift-slab procedure. Thompson’s Water Seal was used as the parting agenton the concrete slabs. About six months after the slabs were lifted, vinyl asbestostile was laid in most of the building. Most of the tile was laid using asphaltemulsion adhesive, but some was put down with an asphalt cut-back type mastic. Afew months after the tile was laid, asphalt mastic started to ooze through the seams.Some of the tile was removed and it was observed that the adhesive was soft under-neath. Most of the adhesive was scraped off and new tile installed without usingany more mastic. A few months later, mastic started to ooze between the seams ofthe new tile. Again the tile was removed, the wet mastic scraped off and new tileinstalled. A few months later, mastic was still oozing between the seams of thetile. It is known in the industry that certain "hot" plasticizers in vinyl asbestostile will cause softening and oozing of the mastic. Also, the oozing might be dueto the parting agent, Thompson’s Water Seal. This is a subject for laboratoryinvestigation.

On the other hand, a number of buildings were inspected which were known to haveconcrete floors treated with a product known as "West Concrete Floor Treatment"

,

manufactured by West Chemical Products, Inc. Resilient tile laid on such treatedfloors appeared to be in perfect condition after periods of from one to three years.The particular product used was said to be a solution of chlorinated rubber inxylene.

- 3 -

3. COMMERCIAL CURING AND PARTING AGENTS

Table 1 is a list of manufacturers of curing And parting agents. Part of the listwas obtained from Sweet’s Architectural Catalog File for 1962 and part from arecent survey disclosed in a letter to Mr. Thomas H. Boone of the Bureau fromMr. C. B. Whittelsey, Jr., Managing Director, Asphalt and Vinyl Asbestos Tile Insti-tute. Table 2 is a list of commercial curing and parting agents, compiled from theabove sources, from manufacturers’ sales literature and technical data and fromrepresentatives of the manufacturers. It cannot be too strongly emphasized thatthese tables are based solely on information from the manufacturers and that theNational Bureau of Standards is not responsible for any errors or misinformationcontained therein.

TABLE 1 . MANUFACTURERS OF CURING AND PARTING AGENTS(Materials are curing agents unless otherwise specified)

The Aquabar CompanyCommercial Trust BuildingPhiladelphia 2, Pennsylvania

Brown & BrownP. 0. Drawer 269Mobile, Alabama

Calbar, Incorporated2626 N. Martha StreetPhiladelphia 25, Pennsylvania

Ceresit Corporation3227 S» Shields AvenueChicago 16, Illinois

AQUABAR DURO-SEAL CONCRETE FLOORTREATMENT

A-500

CRETE-SEAL

CEROSEAL, COLOCURE, INDURITE, LETS GO(parting agent), SURESEAL

Chemex Industries, Inc. CLEAR-TREETP. 0. Box 5072Tampa, Florida

Concrete Service Company C-H-S FLOOR TREATMENT, CURE-SEAL2134 Cherry StreetPhiladelphia 3, Pennsylvania

Creto Company of America, Inc.Il6l3 South Western AvenueLos Angeles 47, California

CRETO

- 4 -

Dewey & Almy Chemical DivisionW. R. Grace & Company62 Whittemore AvenueCambridge 40, Massachusetts

DARAFILM

The Euclid Chemical Company19218 Redwood RoadCleveland 10, Ohio

EUCO FLOOR COAT, EUCO KUREZ

Guardian Chemical Company708 Jefferson Street, N.W.Atlanta 1, Georgia

Representative

:

Thomas E. Turner9218 Fisk RoadRichmond 29, Virginia

CLEAR BOND

A. C„ Horn CompaniesSun Chemical CorporationBuilding Materials Division East2133 85th StreetNorth Bergen, New Jersey

Washington representative:Mr. Lee GroffJE4-3626

HORN CLEAR SEAL, HORN CURE CONCRETECURING COMPOUNDS

Hunt Process Company, Inc.7012 Stanford AvenueLos Angeles 1, California

HUNT PROCESS 112-TU

Imperial Chemical Company1460 W. Hubbard StreetChicago 22, Illinois

LIFT-A-PART (parting agent)

Johnson-March Corporation3018 Market StreetPhiladelphia 4, Pennsylvania

RITECURE CLEAR, RITECURE SPECIALRITECURE WP

Kedmont Waterproofing Company53 W. Jackson BoulevardChicago 4, Illinois

PRESERVA-KURE-SEAL

- 5 -

Lambert CorporationP. 0. Box 151Houston, Texas

LAMBCO CONCRETE CURE No. 64RESIN BASE CONCRETE CURE No. 64RBWHITE PIGMENTED CURE No. 64WBITUMINOUS BLACK CURE No. 64BNO-BOND CURE No. 64NB

(Curing and parting agent)

The Master Builders Co. , Division ofAmerican-Marietta Company2490 Lee BoulevardCleveland 18, Ohip

Representative

:

Mr. W. E. Teuscher6229 N. Charles StreetBaltimore 12, Maryland

DRexel 7-7400

MASTERKURE

McMillan Products DivisionThe Hausman Steel Company2411 Vinewood AvenueDetroit l6, Michigan

DEMIC0N CURE-HARD

W. R. Meadows, Incorporated2 - 18 Kemball StreetElgin, Illinois

SEALTIGHT V-l6?-30, SEALTIGHTGILS0NITE BLACK ASPHALT, SEALTIGHTCURE-HARD

Permiteco, Incorporated1110 E. Monument AvenueDayton 2, Ohio

PERMITE V160

The Peters Company, Div.

,

Toledo Paint & Chemical Company

33 Blucher StreetToledo 1, Ohio

CURE-CRETE No. 200

Philadelphia Quartz CompanyPublic Ledger BuildingPhiladelphia 6, Pennsylvania

"0" SODIUM SILICATE

Presstite DivisionAmerican-Marietta CompanySt. Louis 10, Missouri

Write to:600 Lairport StreetEl Segundo, California

TECHK0TE ANTI-BOND 200

- 6 -

Reardon Industries, Inc.

2837 Stanton AvenueCincinnati 6, Ohio

DUSCURE, SURE-CURE

Sika Chemical Corporation

35 Gregory AvenuePassaic, New JerseyTidewater District Office,

Mr. Douglas Fox, District Manager1221 Leadenhall StreetBaltimore, Maryland

SAratoga 7-3932

ANTISOL, SIKA HARDENER

Sonneborn Chemical and Refining Corp,300 Park Avenue SouthNew York 10, New YorkBuilding Products DivisionWashington representative:

Mr. S. B. Rosenfeid

4953 St. Elmo AvenueWashington, D. C.

0L2-2022, TA9-5045

HYDROCIDE CURING COMPOUND RESIN XKURE-N-SEAL

E. A. Thompson Company, Inc.(formerly By-Chemical Products Co.)Western Merchandise MartSan Francisco 3? California

THOMPSON’S WATER SEAL

Toch Bros. , Inc.521 Fifth AvenueNew York 17, New YorkWashington representative:

Mr. Tillson

4953 St. Elmo AvenueWashington 14, D. C.

652-4141

RIW CURETOX LIQUID, FLINTOX LIQUID,SEALKURE, TOXKURE

The Tremco Manufacturing Company10701 Shaker BoulevardCleveland 4, Ohio

Tretol, Inc., Division ofServicised Products Corporation7252 West 66th StreetChicago 38, Illinois

TREMCRETE

DEKOTE T130DEKOTE T130

- 7 -

Truscon LaboratoriesIndustrial Maintenance DivisionDevoe & Raynolds Company, Inc.

1700 Caniff StreetDetroit 11, MichiganP. 0. Box 9263, Rosslyn StationArlington 9> Virginia

Sales representative;Frank J. Hasse

RE7-2374

AGATEX, TRU-SEAL, TRU-CURE

The Upco Company4801-17 Lexington AvenueCleveland 3? OhioManufacturer’s agent:

A. Albert Pack, Jr.14800 Maydale CourtSilver Spring, Maryland

EVergreen 4-9474

CURECOTE (CURECOAT), POLYCLEAR,UPCO PARAFILM

Wall Products, Inc.6 Honiss StreetBelleville 7» New Jersey(See Tretol, Inc., parent company)

KLEARCURE ^plO and ^30

West Chemical Products, Inc.42-16 West StreetLong Island City 1, New YorkWashington representative:

Don E. Killgore412 Fifth Street, N.W.

NA8-1820

WEST CONCRETE FLOOR TREATMENTWESTCUREWEST BOND BREAKER (Parting agent)

George W. Whiteside Company31st and Michigan DriveLouisville 12, Kentucky

AQUASTATI C CONCRETE CURING COMPOUND

CURING

AND

PARTING

AGENTS,

6

April

1962

8

J3 O4J O d to•H 5 3 X)5 p 0 O -u as 4-1

O d as 0 > O03 O CO CO CO 3 to a to CO CO to CO CO CO to Q dt—4 r—

•

d w t-0 u •H O > § w 0 a. 0 > X50 *4-1 5 0 cS pd P- U 03 CO Pj 44 « B O J-) & •> 0 0d d 0 JD 0 u U as jd 3 £4 0 0 0 03 M O N•w d S-) ns •H nS O CO 0 x< O d O to CQ da jg PD tJ 0 JD © a a 0 • w £4 < MM S as n) CP a H 0 0 as 03 dO

EUCO

FLOOR

HARDENER

CRYSTALS

43us

ou

oo

Uj

CO

44

c•rl

cd

FU

CO

CD

>*

o o125 S3

0)CD

9 -

CA

00c

43 44T3 eo 3) O a> CO CO CO CD> co CD >o 4J O > 43 • 44 CO td * td 0 fla> o

10

01

«c2ij

0)

>ocj

doot—

1

fa

CO

4Jd•rl

ed

fa

co 0qj «d fa r- x> XJ 2 4J (0 2 2 2 XI U d aj CO 0)o c o O cd > O O r—1 co o d d ds0)

0) d§ g g g g

d oo 1

1

Oa

d d cd 0XJ

» cd

> 0O QJ

> Pn p-> CO XJ XJ r-l 4-1 0)o r—

1

a a QJ d QJ QJ QJ cu d *a

>< >< >* ><a P* a

XIcd

Hto a a

><0)2(fl

2cfl

>< d11

M d co CO H zu X £> fa fa fa 2 XJ 2 d) 2 2 2 •r*l1

XJ O o o. O O cdICO XJ u Li oi 2 d d 2 rH 11

0a

Phg § s s g

fa wg

01

2Ph Pd tO2

O

0 o o o o d o S O Ots a c c C O d d d

CO 2 2 2 2 2 2 CO td faQJ d d a d d d QJ d o2 2 ED 2 2 2 >< £3 s

2 dcT•r4

CO

S-i u d •d QJ

11

co

wd•Huy

p >T* os u rj 4J

3 Oy p O dr—

<

o do CO .x >> CO

•H T—i fM

co

a;

>*

co

*

co aQJ -HCO J*a CO

cd

,0

•H d 0)CO u

- 12 -

While the information in Table 2 is incomplete, a study of this table leads toTables 3? 5 and 6.

TABLE 3. MEMBRANE CURING AGENTS COMPATIBLE WITH PAINTS, WITHOUT REMOVAL

Chlorinated rubber base materials : KURE-N-SEAL, WEST CONCRETE FLOORTREATMENT.

Resin base materials s CLEAR BOND, CURE-SEAL, EUCO KUREZ, LAMBCO RESINBASE CONCRETE CURE No. S4RB, POLYCLEAR, WESTCURE

Composition not revealed by manufacturer ("unknown") : CLEAR-TREET

,

CURETcRETE”

(

contains ' no waxes), HORN CLEAR SEAL, TECHKOTE ANTI-BOND(contains no waxes), TRU-SEAL.

TABLE A. MEMBRANE CURING AGENTS COMPATIBLE WITH RESILIENT FLOOR COVERING WITHOUT

REMOVAL.

Chlorinated rubber base : AQUABAR DURO-SEAL, C-H-S FLOOR TREATMENT,KURE-N-SEAL, RIW SEALKURE, and WEST CONCRETE FLOOR TREATMENT

Resin base ; CLEAR BOND, CURE-SEAL, EUCO KUREZ, LAMBCO RESIN BASECONCRETE CURE No. 64RB, POLYCLEAR, SURE-CURE, and WESTCURE

Composition not revealed by manufacturer ("unknown”

)

; CLEAR-TREET,CURE-CRETE No. 200 (contains no waxes), HORN CLEAR SEAL, RITECURE CLEAR,SPECIAL, and WP (contains no waxes), TECHKOTE ANTI-BOND (contains nowaxes), and TRU-SEAL.

TABLE 5. MEMBRANE CURING AGENTS NOT COMPATIBLE WITH PAINTS OR WITH RESILIENT FLOOR

COVERINGS

.

Paraffin base : EUCO KUREZ (paraffin base)

Wax-resin base : EUCO KUREZ (wax-resin or white pigmented base), HORNCURE40W, 50D and C, 60D and C

- 13

TABLE 6. MEMBRANE CURING AGENTS WHICH DISINTEGRATE OR WHICH MUST BE REMOVED BEFORE

APPLYING PAINTS OR RESILIENT FLOOR COVERINGS.

Resin base : CRETE-SEAL, HORNCURE 30D and C, HYDROCIDE CURING COMPOUNDRESIN X

Wax-resin base : CURECOTE, DARAFILM, LAMBCO CONCRETE CURE No. 64,LAMBCO WHITE PIGMENTED CURE No. 6W, SURESEAL

4. CONCLUSIONS

From the information obtained from the manufacturers of curing and parting compounds,it seems obvious that paints and resilient floor coverings cannot be applied over anysuch compounds which contain waxes. However, it is claimed that some wax-resincompositions will disintegrate or can be removed without sandblasting or grinding.Some resin base curing agents are compatible with paints and resilient floor cover-ings and some are not. Chlorinated rubber base membrane curing compounds appear tobe satisfactory as a base for paints or resilient floor coverings.

The compatibility of chlorinated rubber base membrane curing agents with paints andresilient tile is corroborated by the inspection of buildings mentioned earlier inthis report and also on information from the Research and Development Laboratoriesof Armstrong Cork Company. Armstrong Cork Company also have observed the incom-patibility of agents containing waxes. However, according to adhesion tests byArmstrong Cork Company, asphaltic adhesives can be used with any type of curing com-pound.

USCOMM-NBS-DC

.

U. S. DEPARTMENT OF COMMERCELuther I1« Hodges, Secretary

NATIONAL RURtvAP OF STANDARDSA. V. Aatin, Director

THE NATIONAL BUREAU OF STANDARDS

The scope rtf uciivLi.'S of the National Bureau of Standards at its major laboratories in Washington, B.C., andBoulder, Colorado, is suggested in the following listing of the divisions and sections engaged in technical work.

In general, each section carries out specialized research, development, and engineering in the field indicated by

its title. A brief description of the activities, and of the resultant publications, appears on the inside of the

front cover.

WASHINGTON, B.C.

Electricity. Resistance and Reactance. Electrochemistry. Electrical Instruments. Magnetic Measurements.Dielectrics. High Voltage.

Metrology. Photometry and Colorimetry. Refractometry. Photographic Research. Length. Engineering Metrology.Mass and Scale. Volumetry and Dcnsimetry.

Heat. Temperature Fhysics. Heat Measurements. Cryogenic Physics. Equation of State. Statistical Physics.

Radiation Physics. X-ray. Radioactivity. Radiation Theory. High Energy Radiation. Radiological Equipment.Nucleonic Instrumentation. Neutron Physics.

Analytical and Inorganic Chemistry. Pure Substances. Spectrochemistry. Solution Chemistry. Standard Refer-ence Materials. Applied Analytical Research.

Mechanics. Sound. Pressure and Vacuum. Fluid Mechanics. Engineering Mechanics. Rheology. CombustionControls.

Organic and Fibrous Materials. Robber. Textiles. Paper, Leather. Testing and Specifications. Polymer Struc-ture. Plastics. Dental Research.

Metallurgy. Thermal Metallurgy. Chemical Metallurgy. Mechanical Metallurgy. Corrosion. Metal Physics. Elec-trolysis and Metal Deposition.

Mineral Products. Engineering Ceramics. Glass. Refractories. Enameled Metals. Crystal Growth. PhysicalProperties. Constitution and Microstructure.

Building Research. Structural Engineering. Fire Research. Mechanical Systems. Organic Building Materials.Codes and Safety Standards. Heat Transfer. Inorganic 3uilding Materials.

Applied Mathematics. Numerical Analysis. Computation. Statistical Engineering. Mathematical Physics. Op-erations Research.

Data Processing Systems. Components and Techniques. Computer Technology. Measurements Automation.Engineering Applications, Systems Analysis.Atomic Physics, Spectroscopy, Infrared Spectroscopy. Solid State Physics. Electron Physics. Atomic Physics.

Instrumentation. Engineering Electronics. Electron Devices. Electronic Instrumentation. Mechanical Instru-ments. Basic Instrumentation.

Physical Chemistry. Thermochemistry. Surface Chemistry. Organic Chemistry. Molecular SpectroBcopy. Mole-cular Kinetjcs. Mass Spectrometry.

Office of Weights and Measures.

BOULDER, COLO.

Cryogenic Engineering. Cryogenic Equipment. Cryogenic Processes. Properties of Materials, Cryogenic Tech-nical Services.

ionosphere Research and Propagation. Low Frequency and Very Low Frequency Research. Ionosphere Research.Prediction Services, Sun-Earth Relationships. Field Engineering. Radio Warning Services. Vertical Soundings Re-search.

Radio Propagation Engineering. Data Reduction Instrumentation. Radio Noise. Tropospheric Measurements.Tropospheric Analysis. Propagation-Terrain Effects. Radio-Meteorology. Lower Atmosphere Physics.Radio Standards. High Frequency Electrical Standards. Radio Broadcast Service. Radio and Microwave Materi-als. Atomic Frequency and Time Interval Standards. Electronic Calibration Center. Millimeter-Wave Research.Microwave Circuit Standards.

Radio Systems. Applied Electromagnetic Theory. High Frequency and Very High Frequency Research. ModulationResearch. Antenna Research. Navigation Systems.Upper Atmosphere and Space Physics. Upper Atmosphere and Plasma Physics. Ionosphere and ExosphereScatter. Airglow and Aurora. Ionospheric Radio Astronomy.