(a) The asphaltic cement shall consist essentially of a refined, solid-native lake asphalt softened with a liquid petroleum flux.
(b) Refined, solid-native lake asphalt shall be construed to signify any native mineral bitumen produced by refining a crude native lake asphalt which through natural causes, in the process of time, has been reduced to consistency harder then 10 millimeters in penetration, and which, without the addition of any other material has the following characteristics:
Water, none.
Penetration at 77 degrees Fahrenheit, number 2 needle, 100 grams, 5 seconds, not over 3 millimeters.
Percentage total bitumen soluble in carbon tetrachloride, not less than 99 percent.
Residual coke (ash free), not more than 15 percent.
Paraffin scale, not more than 0.1 percent.
Sulphur, not less than 3 percent.
(c) Liquid petroleum flux shall be construed to signify any residuum consisting of the heavier and higher boiling portions of petroleum, free from decomposition products, which has the following characteristics:
Water, none.
Specific gravity at 77 degrees Fahrenheit, between .92 and 1.02.
Penetration at 77 degrees Fahrenheit, number 2 needle, 50 grams, 1 second, not less than 35 millimeters.
Bitumen soluble in carbon disulfide not less than 99.5 percent.
Flash test not less than 350 degrees Fahrenheit.