NATIONAL BUREAU OF

7878

JWweport has been prepared'

feHiifOiiiuliuil SITtff idionh =#'

purposes and is not to be references

'"“ftEPORT

*7

V

Quarterly Report

on

EVALUATION OF REFRACTORY QUALITIES OF

CONCRETES FOR JET AIRCRAFT WARM-UP, POWER CHECK

MAINTENANCE APRONS, AND RUNWAYS

by

J- Vo Ryan, E. C. Tuma and D. K. Ward

U. S. DEPARTMENT OF COMMERCE

NATIONAL BUREAU OF STANDARDS
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 019, 1950. These include the development and maintenance of the national standards of measurement and the provision ol means

and methods for making measurements consistent with those standards; the determination ol 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 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’s unique competence is required.

The scope of activities is suggested by the listing of divisions and sections on 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 or in the journals of professional and scientific societies. The Bureau publishes

three periodicals available 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 preliminary reports on work in progress; and the

Central Radio Propagation Laboratory Ionospheric Predictions provides data for determining

the best frequencies to use for radio communications throughout the world. There are also

five series of nonperiodical 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 Circular 460, Publications of the National Bureau of Standards, 1901 to June 1947 ($1.25),

and the Supplement to National 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): available from the Superintendent of

Documents, Government Printing Office, Washington 25, D.C.
NATIONAL BUREAU OF STANDARDS REPORT

NBS PROJECT NBS REPORT

1002-12-10472 May 6, 1963 7878

Quarterly Report

on

EVALUATION OF REFRACTORY QUALITIES

of

CONCRETES FOR JET AIRCRAFT WARM-UP, POWER CHECK

MAINTENANCE APRONS, AND RUNWAYS

by

J. V. Ryan, E. C. Tuma, D. K. Ward

Fire Research Section

Building Research Division

Sponsored by:

Department of the Navy

Bureau of Yards and Docks

Reference: Task Y-F015-15‘-102

NBS File No. 10.02/10h-72

IMPORTANT NOTICE NATIONAL BUREAU OF SI

for use within the Government, and review. For this reason, tt whole or in part, is not autho Bureau of Standards, Washing

the Report has been specifically

Approved for public release by the

Director of the National Institute of

Standards and Technology (NIST)

on October 9, 2015.

;ss accounting documents intended

i subjected to additional evaluation

3 listing of this Report, either in

le Office of the Director, National

! the Government agency for which

copies for its own use.

U. S. DEPARTMENT OF COMMERCE

NATIONAL BUREAU OF STANDARDS

Quarterly Report

on

EVALUATION OF REFRACTORY QUALITIES OF

CONCRETES FOR JET AIRCRAFT WARM-UP, POWER CHECK

MAINTERANCE APRONS, AND RUNWAYS

by

J. V. Ryan, E. C. Tuma, D. K. Ward

1. Introduction

The purpose of this project is the development of criteria

for the fabrication of jet exhaust resistant concretes. Concretes under development are evaluated by exposure to hot gases

from a combustion chamber. The combustion chamber delivers

these gases at velocities and temperatures approaching field

conditions

.

2. Present Plan of the Investigation

In an attempt to gain more understanding of the mechanism

of spalling and of the factors that determine whether or not

a given concrete spalls under jet impingement, specimen sizes

were chosen to provide different degrees of restraint to

thermal stresses and to the escape of steam from within the

concrete. The instrumentation was designed to provide data on

pressures and temperatures, including temperature gradients

in the 1/2 in. nearest the exposed surface. In addition,

electrical resistance elements were embedded in some specimens

t

Q

; provide an indication of their drying. It was decided to

kjb^p some specimens in the fog room throughout their conditioning, to condition others in air at 73°F and 50% relative humidity, and to attempt to dry others thoroughly.

3* Activities

The specimens of diabase aggregate concrete (Di-2) cast

late in December 1962 were conditioned throughout the quarter,

and observations were made of the changes that occurred in the

specimens

.

A group of specimens were cast from blast furnace slag

aggregate concrete. They were of the same sizes as those of

diabase aggregate concrete and were instrumented in the same

manner.

A study was initiated of the feasibility of accelerated

drying by conditioning in atmospheres at reduced pressures.
2

3.1 Diabase Concrete Specimens

The 82 specimens of diabase aggregate concrete, Di-2

(designed to the same proportions as Di-1, described in

NBS Report 7578, August 2, 1962) , included cylindrical

specimens for exposure to jet impingement, and various

prisms for strength tests, measurement of dimensional

changes, and moisture content. The cylindrical shape iwus

chosen for the jet impingement specimens, in preference to

the square slabs previously used, to permit the use of

commercial waxed cardboard tubing for the large number of

forms required. Jet impingement specimens were cast in

diameters of 3 , 6 , and 12 in., and thicknesses of 2 and 6 in.

The 3“ and 6 -in. diameter specimens were given a coating of

a vapor sealant on their cylindrical surfaces and surrounded

with lightweight aggregate concrete to a total diameter of

12 in. This was done so that the flow pattern of the hot

gases, from the jet, over the exposed faces of all the specimens would be the same. The lightweight aggregate concrete

would not restrain appreciably against thermal stresses

developed in the diabase aggregate concrete.

All the specimens were kept in the fog room for 28 days

after which three of each size for jet impingement, and three

each for shear, flexure, and length change, were placed in a

room maintained at 73°F and 5Q^ percent relative humidity.

Measurements were made frequently of the weights of all the

specimens, and of the electrical resistance and length of

specimens appropriately instrumented. The data obtained £re

summarized in Figures 1 and 2, As of the end of the quarter,

the shapes of the curves in Figure 1 were such as to indicate

that the specimens were nearly ready for jet impingement tests.

Although the conductivity of the concrete had fallen appreciably, previous experience with resistance elements of this

type indicated that very much lower values could be expected,

but only after aging of many months. The data in Figure 1

were interpreted to indicate that the specimens were well

beyond the initial period .of rapid drying from the original

wet state.

3*2 Blast Furnace Specimens

A group of specimens were cast from a single batch of

blast furnace slag aggregate concrete, designated BF-2

(designed to the same proportions as BF-1, described in

NBS Report 757 8 , August 2, 1962). The sizes of specimens,

and the instrumentation incorporated in them were the same
- 3

-

srs' for the Di-2 specimens. The surrounding lightweight

aggregate concrete for the 3“ and 6-in. diameter specimens

was poured in the final days of the quarter. The planned

conditioning program for these specimens is essentially the

same as that described for the Di-2 specimens. The duration

will be determined by the shapes of the curves, similar to

those in Figure 1.

2-3 Vacuum Drying

In view of the fact that the interiors of concrete

specimens continue at very high moisture contents after long

periods in normal drying atmospheres (73°F, 50 percent rh,

760 mm Hg pressure absolute), an attempt was started to learn

if the drying could be speeded up, without affecting strength

adversely, by conditioning in atmospheres at reduced pressures.

For this purpose, groups of nine specimens each of Di-2 and

Di -3 (a small batch to the same design as Di-1 and Di-2) in

the form of 3~ by by 16-in. prisms were cast, kept in the

fog room for 28 days, and then contitioned. Each group of

nine included three with electrical resistance probes and

six with no instrumentation. After 28 days, three of the

latter were placed in 73°F and 50 percent rh "normal drying."

The other six specimens were placed in a chamber that could

be sealed, and the atmosphere within could be pumped down to

about 2 mm "Hg. The chamber was fitted with Kovar seals to

permit connections to the instruments in the specimens, and

with a controller to permit operation at any pressure within

the range of the equipment. The chamber was pumped to the

desired pressure and kept there until conductivity curves

indicated the specimens were in moisture equilibrium.

The Di-2 specimens were kept under a pressure of about

one-half an atmosphere, absolute. After four weeks, they

were removed. The three specimens without... instrumentation,

and the three conditioned at 73 °F 50 percent r|p, were broken

in flexure, the ends broken in compression, and pieces oven

dried for moisture content. The results are given in Table 1.

The specimens of Di -3 were conditioned at absolute

pressure of about 8 mm Hg (± 4mm) , beginning twelve days

before the end of the quarter, and are still in the chamber.
Table 1. Effects of conditioning at reduced pressure of

one-half atmosphere vs. at 73°F, 50 percent rh,

one atmosphere. Specimens of Di-2 concrete.

Conditioning

Normal

Pressure

Reduced

Pressure

Modulus of rupture, psi 880 870

Compressive strength, psi 11350 10400

Weight loss during, percent 14.48 2.37

Moisture content after, percent 4.02 4.91

The results obtained with the Di-2 specimens indicate

slightly lower flexural and compressive strength for the

specimens kept at pressure of about one-half atmosphere.

However, the differences are so small as to be of doubtful

significance. The pieces for moisture content determination

were taken from near the center of the 16-in. length. Had

the pieces from the entire 3“ by by 16-in. specimens been

dried, the difference between those at reduced pressure and

those at atmospheric pressure would have been expected to

be greater.
AGING,

DAYS

FIG

I.

CHANGE

OF

ELECTRICAL

CONDUCTIVITY

(C)

WITH

AGE

FIG 2. CHANGES IN WEIGHT (W) AND LENGTH (L), WITH AGE

« KEPT IN FOG ROOM a l-N 73e

F, 50% RH -AT 28 DAYS

AL/L«,

PERCENT
"
I . S. 1)1 \l{ TMKNT OK COMMERCE

I .nt her II. finders, Secretary

NATION M. BUREAU OF STANDARDS

\. V . A si in, Ilirector

III i: NATURAL BUREAU OF STANDARDS

i ll*' s. o|>(' of act ivitins of the National Bureau of Standards at its major laboratories in Washington, D.C., and

Boulder, Colorado, is suggested in the following listing of the divisions and sections engaged in technical work.

In gem ral, each section carries ait specialized research, development, and engineering in the field indicated by

its tit!*'. A brief description of the activities, and of the resultant publications, appears on the inside ofthe

front cover. WASHINGTON, l).U.

Fleciricity. Resistance and Reactance. Electrochemistry. Electrical Instruments. Magnetic Measurements

Dielof tries. High Voltage.

Metrology. Photometry and Colorimetry. Refractometry. Photographic Research. Length. Engineering Metrology.

Mass and Scale. Volumetry and Densimetry.

Heat. T emperature Physics. 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. Crystal Chemistry.

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

Control s. Polymers. Macromolecules: Synthesis and Structure. Polymer Chemistry. Polymer Physics. Polymer Characterization. Polymer Evaluation and Testing. Applied Polymer Standards and Research. Dental Research.

Metallurgy. Engineering Metallurgy. Microscopy and Diffraction. Metal Reactions. Metal Physics. Electrolysis

and Metal Deposition.

Inorganic Solids. Engineering Ceramics. Glass. Solid State Chemistry. Crystal Growth. Physical Properties.

Crystallography.

Building Research. Structural Engineering. Fire Research. Mechanical Systems. Organic Building Materials.

Codes and Safety Standards. Heat Transfer. Inorganic Building Materials. Metallic Building Materials.

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

Data lYocessing Systems. Components and Techniques. Computer Technology. Measurements Automation.

Engineering Applications. Systems Analysis.

Atomic Physics. Spectroscopy. Infrared Spectroscopy. Ear l ltraviolet Physics. Solid State Physics. Electron

Physics. Atomic Physics. Plasma Spectroscopy.

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

Physical Chemistry. Thermochemistry. Surface Chemistry. Organic Chemistry. Molecular Spectroscopy. Elementary Processes. Mass Spectrometry. Photochemistry and Radiation Chemistry.

Office of Weights and Measures. BOULDER, COLO.

Cryogenic Engineering Laboratory. Cryogenic Equipment. Cryogenic Processes. Properties of Materials. Cryogenic Technical Services.

CENTRAL RADIO PROPAGATION LABORATORY

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 Research.

Radio Propagation Engineering. Data Reduction Instrumentation. Radio Noise. Tropospheric Measurements.

Tropospheric Analysis. Propagation-Terrain Effects. Radio-Meteorology. Lower Atmosphere Physics.

Radio Systems. Applied Electromagnetic Theory. High Frequency and Very High Frequency Research. Fre- quency Ltilization. Modulation Research. Antenna Research. Radiodetermination.

Upper Atmosphere and Space Physics. Upper Atmosphere and Plasma Physics. High Latitude Ionosphere

Physics. Ionosphere and Lxosphere Scatter. Airglow and Aurora. Ionospheric Radio Astronomy.

RADIO STANDARDS LABORATORY

Radio Physics. Radio Broadcast Service. Radio and Microwave Materials. Atomic Frequency and Time-Interval

Standards. Radio Plasma. Millimeter-Wave Research.

Circuit Standards. High Frequency Electrical Standards. High Frequency Calibration Services. High Frequency

Impedance Standards. Microwave Calibration Services. Microwave Circuit Standards. Low Frequency Calibration

Services.

U SCCMIV-N B S-DC