is a method for determining the penetration, or consistency, of semi-solid bituminous (see bitumen) materials, in a penetrometer under conditions prescribed by test method ASTM-D-5. The test sample is melted and cooled under controlled conditions, then a weighted standard needle is positioned at the surface of the sample and allowed to penetrate it, by means of gravity, for a specified time. The penetration is measured in tenths of a millimeter.

Also see penetration grading (asphalt), viscosity (asphalt).