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Cork insulation; a complete illustrated textbook on cork insulation ...

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; the<br />

' At<br />

STRUCTURAL SUGGESTIONS 231<br />

2.—COMPOSITION OF PETROLEUM ASPHALTS.<br />

Mexi- Mid-C<strong>on</strong>tinent Calif- Stanocan<br />

Air Blown ornia lind*<br />

Bitumen 99.5% 99.2% 99.5% 99.8%<br />

Mineral Matter 0.3% 0.7% 0.3% 0.3%<br />

Specific Gravity 1.040 0.990 1.045 1060<br />

Fixed Carl <strong>on</strong> 17.5%. 12.0% 15.0% 17.5%<br />

Melting Point °F 140 180 140 135<br />

Penetrati<strong>on</strong> (77° F.) 55 40 60 SO<br />

Free Carb<strong>on</strong> 0.0 0.0 0.0 0.0<br />

Sulphur (ash frte basis) 4.50% 0.60% 1.657o 0.35%<br />

Petroleum Ether Soluble 70.0%) 72.0% 67.0%, 70.0%<br />

Cementing Properties good poor good gooa<br />

Ductility (squarp mold) 45 cm 2 cm 70 cm 100+<br />

Loss at 32° F. 5 hrs 0.2%, 0.1% 0.2%, 0.1%<br />

Heat test adherent smooth adherent scaly<br />

These values were obtained by methods of testing as published<br />

by the K. C. T. L., Bulletin No. 15, which are in many<br />

particulars slightly different from the methods adopted by<br />

the American Society for Testing Materials, and c<strong>on</strong>sequently<br />

the values of the K. C. T. L. are given here for general infor-<br />

mati<strong>on</strong> <strong>on</strong>ly and are in no way to be c<strong>on</strong>fused with the values<br />

called for in a Specificati<strong>on</strong> for Asphalt Cement for Cold Storage<br />

Insulati<strong>on</strong>, or with an Asphalt Primer for Use with Asphalt<br />

Cement.<br />

The "Heat Test" menti<strong>on</strong>ed in the K. C. T. L, Table No. 2,<br />

should be of interest, as follows<br />

Resistance of Asphalt Cement to Oxidati<strong>on</strong>, K, C, T. L., 1919<br />

A strip of thin sheet ir<strong>on</strong> 2 inches wide and 6 inches l<strong>on</strong>g is<br />

covered <strong>on</strong> its lower 4 inches with the melted asphaltic cement. This<br />

strip is placed in an oven at 275° F. for 15 minutes and allowed to<br />

thoroughly drain.<br />

It is removed from the oven and allowed to cool, then placed in<br />

an electrically heated oven at a temperature of 450° F. for <strong>on</strong>e hour.<br />

the end of the hour, the door of the oven is opened and the heat<br />

is turned off, the specimen being allowed to remain in the oven.<br />

The oven shall be <strong>on</strong>e having outside dimensi<strong>on</strong>s of 12x12x12<br />

inches with an opening in the top 1 cm. in diameter, the heating elements<br />

being in the bottom of the oven. The resistance shall be so<br />

distributed that the heat is uniform throughout the oven. The lower<br />

end of the strip shall be suspended so that it is at least 3 cm. from<br />

bottom of the oven.<br />

The resistance is preferably so arranged that three different heats<br />

can be maintained with a snap switch such that the lowest heat is<br />

325° F., the medium heat is 400° F. and the highest heat is 450° F.<br />

After being subjected to these tests, the film of asphalt should be<br />

brilliant and lustrous, should not be scaly and fragile, should adhere<br />

fi firmly to the metal and should not be dull and cheesy in texture.<br />

'(Cracked-pressure tar residue. ")<br />

:

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