CHAPTER Ii, SECTION 18
Figure 2-24.
Broken Limonite Test Cylinder
conducted to provide design information for the
improvements to the airstrip at site Fred and
the Peter-Oboe airstrip.
Paint duranility tests were conducted under
the supervision of the laboratory; materials such
as gypsum and plasticized sealers were tested
for effectiveness; the breaking strength of cables
and the working load of steel springs in tension
and compression were determined. Services such
‘as in-place soil density tests were provided for
various User groups. The laboratory provided
information for the design section in regard to
effect of shear values on creosoted timbers.
Materials for the construction of waste lines
were tested for the distillation department for
resistance to acids.
A careful check was maintained by the
testing taboratory on the condition, storage and
consumption of cement. When a new shipmem
of cement was received at Jobsite, samples were
taken and tested in accordance with Spec.
ASTM C-15-49. These tests consisted of fineness, soundness, loss of ignition, time of set and
mortar strength tests.
Limonite (which is heavy weight shielding
concrete) amounting to slightly less than 500
cubic yards was again placed during the current Operation.J ith the experience gained durprogram of tests and mix designs for CASTLE,
no particular difficulties arose. Limonite concrete
pouts were somewhat slower than coral concrete
pours because the weight of a batch of this type
of concrete necessarily reduced the capacity of
the concrete mixers. Although more cement per
yard was utilized in these mixes than in coral
concrete mixes, no adverse thermal cracking
was noted. Figure 2-24 shows a broken limonite
cylinder. This cylinder broke at over 3500 psi
and yet it will be noted howlittle, if any, bond
exists between the scrap steel and limonite ore
grout of which the heavy shielding concrete is
composed. A limonite concrete mix was designed
to produce a unit weight of 312 pounds per
cubic foot for a small “cushion’: without increasing mixing and placing difficu'ties. Compressive strengths in excess of 3000 psi were
realized from these dense mixes but the amount
of mixing water had to be sharplyrestricted
i)
oe
to produce the required unit weights. Compres4
t
{
,‘
‘I Page 2-49
I,
12
\
{
|
meine,
ereAeEE Metis «nem