Treating concrete surfaces with paraffin


Material Information

Treating concrete surfaces with paraffin
Physical Description:
4 p. : ill., diagrams ; 26 cm.
Salo, Albert E
Lawrence Radiation Laboratory
U.S. Atomic Energy Commission -- Technical Information Service
University of California Radiation Laboratory
Place of Publication:
Berkeley, CA
Publication Date:


Subjects / Keywords:
Concrete -- Finishing   ( lcsh )
Paraffin wax   ( lcsh )
federal government publication   ( marcgt )
non-fiction   ( marcgt )


Statement of Responsibility:
by Albert E. Salo.
General Note:
General Note:
"May 18, 1955."
General Note:
"United States Atomic Energy Commission, Technical Information Service, Oak Ridge, Tennessee."

Record Information

Source Institution:
University of Florida
Rights Management:
All applicable rights reserved by the source institution and holding location.
Resource Identifier:
aleph - 005254726
oclc - 424669906
System ID:

Full Text




Albert E. Salo

K N'

May 18, 1955

Radiation Laboratory
University of California
Berkeley, California

L Technical Information Service, Oak Ridge, Tennessee


Subject Category, CHEMISTRY.

Work performed under Contract No. W-7405-eng-48.

This report has been reproduced directly from the best
available copy.

Reproduction of this information is encouraged by the
United States Atonic Energy Commission. Arrangements for
your republication of this document in whole or in part
should be made with the author and the organization he

AEC, Oak Ridge, Tenn.


The Atomic Energy Commission makes no representation or warranty
as to the accuracy or usefulness of the Information or statements contained
in this report, or that the use of any Information, apparatus, method or
process disclosed In this report may not Infringe privately-owned rights.
The Commission assumes no liability with respect to the use of, or for
damages resulting from the use of, any information, apparatus, method or
process disclosed In this report.


By Albert E. Salo

It is difficult or impossible to remove radioactive contamination from ordinary concrete
surfaces. A penetrating application of paraffin, however, seals the pores of the surface and
makes decontamination relatively easy because it reduces absorption of liquids that might
carry radioactivity. Molten paraffin (mp 1250F) is applied to a clean concrete surface that has
been heated to about 500F. Penetration depths of 1/4 inch are usual, but penetration may range
up to '/4 inch. Pore spaces in the concrete are sealed when the paraffin cools.
The concrete surface is prepared by acid etching and wire brushing. A thorough rinse with
running water is followed by a drying period of at least four days. Batteries of infrared lamps
may be used to help the drying process.
In melting the paraffin, provisions should be made to conduct fumes away and to extinguish
any flash flames. Probability of flashing can be reduced if an electric hotplate is used in pref-
erence to an open flame, and if the liquid temperature is kept below 2000F.
A wide-tip oxyacetylene torch is used to heat the concrete. Great care must be taken in
applying the flame slowly and evenly. Areas of 5 to 10 square feet are heated at one time. The
torch operator should be protected against the possibility of spelling particles by wearing a
face shield and heavy clothing. Molten paraffin is brushed on the heated section until no more
absorption takes place. Paraffin requirement is approximately 0.1 pound per square foot.
A layer of paraffin more than a few mils thick on the surface is both unnecessary and un-
desirable. Protection against possible radioactive contamination is provided by the paraffin
that is absorbed into the concrete, not that which remains on the surface. An excess on the
surface makes floors slippery and dangerous.
Depth of penetration can be checked by the use of concrete test blocks, similar in texture
and mix to the surface to be treated. After treatment the test block may be fractured with a
hammer and chisel. The penetration line will usually be clearly discernible. Fig. 1 shows a
typical cross section of a treated and fractured test block. The dark band at the top of the
piece indicates how far the paraffin has penetrated into the block from application at the top.
The band is wider at the left because in this area penetration also took place through the side
surface. The dark spot on the right of the face and slightly below the surface penetration line
indicates where a small amount of paraffin penetrated through a fissure into the underlying
body of concrete.
Fig. 2 shows a stairway that has been treated with paraffin in the manner described. This
work was done under the auspices of the U. S. Atomic Energy Commission.

*Permission for publication of this information in whole or in part is granted by the author
and the University of California Radiation Laboratory operated for the United States Atomic
Energy Commission.



Fig. 1 -Treating concrete with paraffin.

Fig. 2- Treating concrete with paraffin.

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