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NATIONAL BUREAU OF STANDARDS REPORT

5353

QUARTERLY REPORT

ON

EVALUATION OF REFRACTORY QUALITIES OF

CONCRETES FOR JET AIRCRAFT WARM-UP , POTT ER CHECK,

MAINTENANCE APRONS, AND RUNWAYS

ez-3¥t'~SS 5*8

|

s5*sh»

K.VV ."/f.S IrrUI

iesAv?* M,J o

i.r

by

* L. Pendergast , E. C* Tuma , L» E. Hong

and E« Trattner
THE NATIONAL BUKEALJ OF STANDARDS

Functions and Activities

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

5, 1901, as amended h\ Congress ih Public Law 619, 1950. These include the development and

maintenance of the national 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 Agencies 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 ami information services. A major portion of the Bureau’s v»ork is performed

for other Government Agencies, particularly the Department of Defense and the Atomic Energy

Commission. The scope of activities Is suggested b\ the listing of divisions and sections on the

inside of the back cover.

Reports and Publications

The results of -the Bureau’s work take the form of either actual equipment and devices or published papers and reports. Reports are issued to the sponsoring agency of a particular project or program. Published papers appear either in the Bureau’s own series of publications or in the

journals of professional and scientific societies. The Bureau itself publishes three monthly periodicals, available from the Government Printing Office: The Journal of Research, which presents

complete papers reporting technical investigations; the Technical News Bulletin, which presents

summar) and preliminary reports on work in progress; and Basic Radio Propagation Predictions,

which provides data for determining the best frequencies to use for radio communications throughout

the world. There are also five series of nonperiodical publications: The Applied Mathematics

Series, Circulars, Handbooks, Building Materials and Structures Reports, and Miscellaneous

Publications.

Information on the Bureau’s publications can be found in NBS Circular 160, Publications of

the National Bureau of Standards ($1.25) and its Supplement ($0.75), available from the Superintendent of Documents, Government Printing Office, Washington 25, D. C.

Inquiries regarding the Bureau’s reports should be addressed to the Office of Technical information, National Bureau of Standards, Washington 25, D. C.
NATIONAL BUREAU OF STANDARDS REPORT

HES PROJECT NBS REPORT

0903-20-4428 July 1, 1957 5353

QUARTERLY REPORT

ON

EVALUATION OF REFRACTORY QUALITIES OF

CONCRETES FOR JET AIRCRAFT WARM-UP , POWER CHECK,

MAINTENANCE APRONS, AND RUNWAYS

by

W. L. Pendergast, E« C s Tuna , L. E. Mong

and E. Trattner

Refractories Section

Mineral Products Division

Sponsored by

Department of the Navy

Bureau of Yards and Docks

Reference: NT4-59/NY 420 003-1

NBS File No. 9.3/1134-C

Approved

:

Dr. Samuel Zerfoss

Chief, Refractories Section

IMPORTANT NOTICE

NATIONAL BUREAU OF STAI

intended for use within the Gi to additional evaluation and ret listing of this Report, either in the Office of the Director, Nati however, by the Government a; to reproduce additional copies

Approved for public release by the

Director of the National Institute of

Standards and Technology (NIST) on October 9, 2015.

ogress accounting documents

nally published it is subjected

aproductioh, or open-iiterature on is obtained in writing from

iuch permission is not needed,

repared if that agency wishes

U. S. DEPARTMENT OF COMMERCE

NATIONAL BUREAU OF STANDARDS
i
QUARTERLY REPORT

ON

EVALUATION OF REFRACTORY QUALITIES OF

CONCRETES FOR JET AIRCRAFT WARM-UP, POWER CHECK,

MAINTENANCE APRONS, AND RUNWAYS

1. INTRODUCTION

This phase of the project includes the determination of

the cause or causes of failure that occur in concrete aprons

and runways exposed to jet exhaust gases. A combustion

chamber that delivers hot gases at velocities and temperatures

approximating those of field conditions is being used. The

approach includes instrumentation of the concrete test panels

to determine the heat gradients and stresses set up during

flame impingement at several locations on the test area and

at varying depths below the surface.

2. ACTIVITIES

2.1 Pressure Developed in Concrete

During Heating

The apparatus which consisted of a bomb, pressure gage,

and connecting fittings made entirely of stainless steel,

shown in Figure 2, N.B.S. Report 5233, April 15, 1957, was

used in the tests during this quarter.

The first three heating cycles were made with the bomb

charged with neat Portland cement, cured 10 days in the fogroom, and dried under vacuum at room temperature. In these

tests a second lot of silicone oil was used to transmit the

pressures. The maximum pressure developed during the first

heating was 900 ps i , 800 ps i in the second, and 750 ps i in

the third. Residual pressures on cooling to room temperature
}
-2 —

were 150, 135, and 50 ps i respectively. These pressures were

relieved before the succeeding test. An analysis of the gas

causing this residual pressure gave 0.87= COg, O.87o 0^, and

no CO. The remainder of the gas was combustible and was

probably s ome form of hydrocarbon derived from the new lot

of silicone oil. Since this oil proved to be unstable it was

decided to use mercury as the pressure transmitting liquid.

The second bomb charged with water only and mercury as

the transmitter was given two heating cycles. During the

first of these heating cycles abnormally high pressures

developed due to the differential thermal expansion of the

bomb and its contents. Before the second heating cycle a necessary amount of mercury was removed and the resulting

pressure-temperature curve was similar to the steam tables.

The third bomb contained neat Portland cement, fog-room

# cured for 45 days, and dried at room temperature under vacuum.

The results of the three heating cycles on this bomb agreed.

This agreement indicates that possible alteration in the

mine ra logica 1 composition of the cement did not seriously

effect the pressure-temperature relation. Deviation from

the steam tables were observed for temperatures below 200°C

but were not present above this temperature. This deviation

in the lower region (100-200°C) indicated that, on heating,

higher temperatures were required than those given in the

steam tables; while on cooling the opposite was true. This

deviation may indicate that chemical bonding of water is a

-3-

factor in the temperature-pressure relations at the lower

temperatures. The extent of this effect, amounted to a maximum temperature alteration of but 17°C. A graph of the

temperature-pressure relation for the first heating cycle

is shown in Figure 1.

Samples of the neat cement were taken for X-ray

examination following the third heating cycle, after drying

at 110°C, and after heating at 350°C.

A third bomb was charged with brick aggregate and water,

equivalent to that amount used as mixing-water for concrete.

The pressure-temperature relation during a heating cycle

coincided very closely with the steam curve,

A fourth bomb contained concrete designed with brick

aggregate and Portland cement, fog-room cured for 15 days

with no drying treatment. The pre s sure -tempe rat ure curve

for the heat ing ‘cycle was similar to that shown in Figure 1.

Inasmuch as the thermocouple located at the middle of

the charge was sometimes erratic due to the presence of

mercury and occasionally imperfect insulation the use of this

thermocouple was discontinued. The temperature measurements

can be made with sufficient accuracy by means of a thermocouple

attached to the outside of the bomb for the heating rates

used (50°C per hour). The use of the external thermocouple

only will also enable us to obtain weight changes of the

bomb contents following various heat treatments.

100

000

900

800

700

600

500

400

300

200

100

0

T

TEMPERATURE , °C

- 4 -

The pressure-temperature curves shown in Figures 3 and 4

of N.B.S. Report 5233 were probably in error due to the

unknown properties and reactions of the silicone oil.

The data on the neat Portland cement, brick aggregate,

and concrete designed using these constituents indicate that

pressure, equivalent to the desired strength, (650 ps i

)

would be developed in concrete at temperatures in the

vicinity of 250°C. Inasmuch as the strength of the concrete

decreases as the temperatures of exposure increases the

developed steam pressure could be expected to fracture the

concrete at temperatures below 250°C unless a means of egress

for the steam is available. Some fractures, evidenced by

abrupt changes in temperatures of buried thermocouples,

shown in Figure 2, N.B.S. Report 4767, July 20, 1956,

occurred in the range 225 to 325°C. The fractures, occurring

at higher temperatures, ranging to 500°C, Figures 2 and 3

of the same report, may have been delayed due to moisture

loss through the concrete.

Bombs charged with Lumnite or Alooa XCA-25 high-alumina

hydraulic cements have been prepared. It is possible that

these cements may perform more advantageously in the bomb test.

The thermal length changes of the comparatively pure

high-alumina hydraulic cement (Alcoa XCA-25) cured 28 days

in fog-room and dried 14 days at 35 percent relative humidity

at 77°F is shown in Figure 2.—^ Below 1000°C the length — ^ Determined by S. Schneider, Refractories Section.

-5-

changes are comparatively small and differ markedly, from

the other cements included in this project, in that a large

expansion occurs between 1000 and 1180°C for the cured

cement. This inflection was absent in the cooling curve and

the expansion and contraction curves of the material after

heating to 1280°C. This inflection would not be involved in

considering its use for jet aprons.

2.2 Jet Impingement Tests

The results of the jet impingement tests on ten panels

having diabase aggregate are given in Table I. The second

lot, P-D^-2 were duplicates of P-D^-l. Panels 1, 2, and 3

of the second lot were tested after short drying periods and

had considerably larger losses in the test than those dried

for longer periods. Larger losses occurred in the second

lot as shown by the comparison of P-D^-2-4 to P-D^-l-1 and 2,

and of P-D.-2-5 to P-D.-1-5. Such differences in results

l l could be attributed to experimental errors.

The three panels Al-B-3 were designed with Alcoa (XCA-25)

cement and crushed building brick aggregate were outstanding

because they show no loss after 5, 10, or 15 minutes exposure

after relatively short drying periods of 7, 14, and 28 days.

An analysis of the recorded temperatures (at six locations)

taken from these panels indicated that the temperature for

corresponding locations in P-D^-l and P-D_^-2 panels were in

fair agreement. The comparison is limited by the large

variation in temperature at the same location for the five
)
LENGTH

CHANGE

,

PERCENT

TEMPERATURE ° C

- 6 -

panels of a single lot and also by the possibility of

defective thermocouples. The results of the tests on three

panels Al-B-3-1, 2, and 3 indicate that the temperature at

c the center surface of the panels was about 300 C less than

that recorded for panels containing Portland cement.

The higher thermal conductivity of the Alcoa (XCA-25)

may account for this difference. The thermal conductivity

of samples of this type concrete will be determined.

2.3 A Study of the Mechanism by which Water Vapor

Travels Through Concrete

The study of the mechanism by which water vapor travels

through concrete, the rate of transfer from a high-pressure

to a low-pressure, and the effect of environmental conditions

on the rate of transfer, has been continued.

Two flanged cylindrical chambers were constructed, each

to maintain different constant relative humidities. A

three to four-inch cross-section was cut from a six by

twe lve-inch concrete cylinder sealed on the outside surface

and placed between the two chambers. The section of concrete

was sealed with asphalt emulsion and brought to equilibrium

by storage in a 75 percent relative humidity atmosphere.

Constant relative humidities are maintained in the cylindrical

chambers by two small diaphragm pumps that circulate air of

a constant relative humidity through the respective chambers.

Small sealed plastic containers charged with appropriate

salt solutions serve as the source of the selected relative

Table

I.

Spalling

Loss

of

Panels

During

Jet

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-7-

humidity and the small pumps convey the atmosphere from

these plastic containers to larger cylindrical chambers.

At regular t ime- inte rva Is the plastic containers, together

with their contents, are weighed and the gain or loss in

weight is noted. When the loss in weight on the one side

equals the gain in weight on the other the concrete has

reached equilibrium, that is, the concrete is under a higher

realtive humidity (75 percent) on one side and a lower

relative humidity condition on the other. At this point

the rate of vapor transfer under given conditions can be

established. For this series of tests concrete cylinders

of three different cement contents were cast, and are being

cured in the fog-room, to be used as needed. The difference

of rate of transfer through a high, medium, and low strength

concrete will be studied.

This apparatus, with modifications, will be used to

study the rate of transfer of neon gas through wet and dry

concrete. Assuming that neon gas is not adsorbed by concrete

at room temperature the difference in rates of transfer will

make it possible to estimate how much of the vapor transfer

is due to gaseous diffusion and how much to some other

me chan i sm

.

3. OCCURRENCE OF DIABASE

A review of the literature describing the location, extent

of the deposite, petrograph analysis, and chemical analysis

of diabase throughout the country is underway. If possible

- 8 -

samples will be obtained from various parts of the country

and examined. The results of such an examination will

assist in preparing specification for this material as an

aggrega te

.

4. LITERATURE

A review of the following articles was made during this

quarter

:

111 "Properties of Some Calcium Aluminate Cement

Compositions," Gitzen, Hart, MacZura,

Journal American Ceramic Society, Vol. 40,

No. 5, May 1957.

Abst ract

The properties of some high-purity calcium aluminate

cement compositions in that portion of the lime-alumina

system from 64 to 86 percent alumina were investigated. The

laboratory preparation of seven hydraulic compositions in

this system is described. Methods of appraising the

properties, both in the neat cement and in castable formations, are given. Data on bond strength, setting properties, heat of hydration, refractoriness, and aging

characteristics are presented. A cement composition represented by the empirical molar formula CaO^.SAl^O^ was

found to be optimum for balanced bond strength and refractoriness in h igh-tempe ra tur e castables.

-9-

/ 2 / "Phosphate-Bonded Alumina Castables: Some

Properties and Applications," Gitzen,

Hart, MacZura, American Ceramic Society

Bulletin, June 1956.

Abstract

Refractory castables composed of a sintered aluminum

oxide grog bonded with phosphoric acid have been developed

and tested. Both heat-setting and cold-setting compositions

are described. These castables are characterized by high

bond strength which is developed at 650°F and remarkable

resistance to erosion over a wide temperature range. The

influence of thermal shock and phase inversions on bond

strength was investigated. Castable preparations, methods

of placement and curing procedures are discussed. Data

collected from several field applications indicate excellent

serviceability of these castables in the temperature range

of 3 4 0

0 ° F

.

/ 3 / "Structural Refractory Concrete," Herman G.

Protze, Journal American Concrete Institute,

Vo 1 . 28, No. 9, March 1957 .

Abs t ra c t Theoretical and practical problems in the construction

of jet engine test cell exhaust structures are considered

including the development and use of proper materials,

mixtures, eguipment , and methods of installation of durable

- 10 -

structural refractory lightweight alunino\is cement concretes.

The author draws from laboratory and field experiences on

four projects in recommending current optimum tehcnigues for

such work.

5. CONFERENCES

A conference was held at this Bureau, April 25. The

names of those attending follow:

Commander F. C. Hanshe

Everet Hamer, 11th Naval District

L. A. Palmer

P . Knoop

P . P . B r own

I. C. Schoonover

S . Zerf os s Bruce Foster

William Pendergast

Bureau of Yards

and Docks

National Bureau

of Standards

The results of the work completed during the first nine

months of this fiscal year were reported and discussed.

As a result of the discussion between the research

group of the Bureau of Yards and Docks and members of the

staff of the National Bureau of Standards it was decided

that the following items should be included in the program

for the ensuing year.

1. (a) A continuation of the bomb tests on concrete

and neat cement to evaluate steam pressures developed at

given temperatures.
>

I

.*
- 11 -

(b) Modify the pore system of concrete by introducing

large connecting pores by methods of fabrication, air

entrainment etc without appreciably lowering strength.

2- (a) Correlation of the degree of dryness of concrete

with its failure in the jet blast test.

(b) The determination of the amount and distribution

of water from humidity measurements within concrete.

3. (a) A study of the mechanism by x^hich water vapor

travels through concrete.

4. Identification of concrete susceptible to failure

primarily by (a) development of steam pressure, (b) thermal

s pa 1 1 i ng .

Dr. Zerfoss reported briefly on items relevant to this

project that were discussed at the last meeting of the

Advisory Group, Ohio River Division Laboratories, Corps of

Engineers, U. S. Army, formed for the guidance of the study

of pavements resistant to the action of jet and rocket

exhaust

.

U. S. DEPARTMENT OF COMMERCE

Sinclair Weeks, Secretary

NATIONAL BUREAU OF STANDARDS

A. V. Astin, Director THE NATIONAL BUREAU OF STANDARDS

The scope of activities of the National Bureau of Standards at its headquarters in Washington,

D. C., and its major field laboratories in Boulder, Colorado, is suggested in the following listing of

the divisions and sections engaged in technical work. In general, each section carries out spe- cialized research, development, and engineering in the field indicated by its title. A brief

description of the activities, and of the resultant reports ami publications, appears on the

inside front cover of this report.

WASHINGTON, D. C.

Electricity and Electronics. Resistance and Reactance. Electron Tubes. Electrical Instruments. Magnetic Measurements. Dielectrics. Engineering Electronics. Electronic Instrumentation,

Electrochemistry.

Optics and Metrology. Photometry and Colorimetry. Optical Instruments. Photographic

Technology. Length. Engineering Metrology.

Heat and Power. Temperature Physics. Thermodynamics. Cryogenic Physics. Rheology

and Lubrication. Engine Fuels.

Atomic and Radiation Physics. Spectroscopy. Radiometry. Mass Spectrometry. Solid State Physics. Electron Physics. Atomic Physics, Nuclear Physics. Radioactivity. X-rays. Betatron. Nucleonic Instrumentation, Radiological Equipment. AEC Radiation Instruments. Chemistry. Organic Coatings. Surface Chemistry. Organic Chemistry. Analytical Chemistry.

Inorganic Chemistry. Electrodeposition. Gas Chemistry. Physical Chemistry. Thermochemistry. Spectrochemistry. Pure Substances.

Mechanics. Sound. Mechanical Instruments. Fluid Mechanics. Engineering Mechanics.

Mass and Scale. Capacity, Density, and Fluid Meters. Combustion Controls.

Organic and Fibrous Materials. Rubber. Textiles. Paper. Leather. Testing and Specifications, Polymer Structure. Organic Plastics. Dental Research.

Metallurgy. Thermal Metallurgy. Chemical Metallurgy. Mechanical Metallurgy. Corrosion.

Metal Physics.

Mineral Products. Engineering Ceramics. Glass. Refractories. Enameled Metals. Concreting

Materials. Constitution and Microstructure,

Building Technology. Structural Engineering. Fire Protection. Heating and Air Conditioning. Floor, Roof, and Wall Coverings, Codes and Specifications.

Applied Mathematics. Numerical Analysis. Computation. Statistical Engineering. Mathematical Physics.

Data Processing Systems. SEAC Engineering Group. Components and Techniques. Digital

Circuitry. Digital Systems. Analogue Systems. Application Engineering.

• Office of Basic Instrumentation • Office of Weights and Measures

BOULDER, COLORADO

Cryogenic Engineering. Cryogenic Equipment. Cryogenic Processes. Properties of Materials.

Gas Liquefaction.

Radio Propagation Physics. Upper Atmosphere Research. Ionospheric Research. Regular

Propagation Services. Sun-Earth Relationships.

Radio Propagation Engineering, Data Reduction Instrumentation. Modulation Systems.

Navigation Systems. Radio Noise. Tropospheric Measurements. Tropospheric Analysis. Radio

vsJems Application Engineering.

Radio Standards. Radio Frequencies. Microwave Frequencies. High Frequency Electrical

Standards. Radio Broadcast Service. High Frequency Impedance Standards. Calibration

Center. Microwave Physics. Microwave Circuit Standards.