Memorandum from R. L. Murray and A. C. Menius to Dr. Clifford K. Beck
July 14, 1951
July 14, 1951
TO: Dr. Clifford K. Beck
FROM: R. L. Murray and A. C. Menius
SUBJECT: Reactor Concrete Tests (Preliminary Report)
This report summarizes the recent investigations of reactor concrete
mixes by Professor C. R. Bramer of the Civil Engineering Department. We are
glad to report that the experiments were very successful, thanks to Mr. Bramer's
Two shipments of barytes aggregate were tested.
The first of these consisted of two separate sizes: what will be labeled
- 1. Sweetwater, Tennessee - supplied by L. A. Woods.
- 2. Cartersville, Georgia - supplied by New Riverside Ochre Co.
"coarse," ranging from 1" maximum diameter stones to about 1/4", with very
little fine material; what will be labeled "fine," ranging from a 1/4" maximum
down below that transmitted by a 16 mesh screen; of the fine material 62% goes
through that screen, the rest is retained.
The second shipment was a uniformly graded mixture ranging from 1" down to
The Colemanite was the sand from the West Coast; Portland cement types I, II
and III (High-early) were on hand.
In previous tests, the mortar had failed to set, which was attributed
by Oak Ridge people to be due to the large amount of water that is normally
added to make the consistency proper for pouring. Thus in the present experi-
ments, efforts were made to minimize the water content.
As the basic proportions of materials, the Oak Ridge Figures for a cubic yard
|Portland Cement||830 lb.|
|Water||310 lb. (37.5 gal.)|
The following table gives the composition of the several batches used
to make test cylinders:
A. June 19:
One seventeenth (1/17) of the above weights were taken. Assuming that the
Sweetwater barytes coarse was 3/4" ASTM and the fine was 3/8," the latter
was acreened to remove all material smaller than 16 mesh. The ratio of
"coarse" to "new fine" was then taken as 16.6 to 1. The weights (in lb.)
|New fine barytes||13.25||Air Temperature 80°|
|Type III cement||48.8|
- One cylinder was made with 21.5 lb. of water which was 11.8% more than the
Oak Ridge specification, the slump was negligible. A second was made with
an arbitrary added amount of water giving a one-inch slump.
- The first cylinder set up slowly, and after a week is still not completely
firm; the second was even softer.
B. June 21.
- The fraction of the cubic yard mix used in this case was 1/85. The alterna-
tive of type II cement was tried, with the weights below:
|New fine barytes||2.65||Air Temperature 82°|
|Type II cement||9.80|
|Water||3.64 (Oak Ridge)|
C. June 21.
- The fine barytes was not screened in this test. Proportions were adjusted
|Fine barytes||10.65||Temperature and Humidity as|
|Type II cement||9.80|
|Water||4.14 (11.4% over specification)|
- Neither of these mixes have become firm or show any signs of even doing so.
D. June 22.
- On the assumption that the dissolved colemanite inhibits the portland cement
action, the colemenite was not added until the mixture of cement, aggregate
and water had set for 45 minutes. The Georgia barytes was used.
|Barytes||46.70||Air temperature 82°|
|Type III cement||9.80|
|Water||4.00 (11% excess)|
- This mix set up in about 24 hours and after three days is judged to be quite
It would be concluded tentatively that:
It is estimated that the water excess might be cut in half, or even more if a
- a. Georgia Barytes is a preferable aggregate, from the standpoint of
uniformity of gradation (and cost).
- b. Type III cement should be used.
- c. Special "late" mixing of colemanite is needed.
Professor Bramer states that a contractor can do this.
wetting agent such as Darex is used. Tests on those ideas and a neutron
absorption experiment to determine whether the colemanite is uniformly enough
distributed are planned.
The specific gravity was measured to be 3.4.