ASTM D2493 Standard Viscosity-Temperature Chart for Asphalts
1. Scope
1.1 The viscosity-temperature chart covered by this standard is a convenient means of plotting data for estimating the viscosity of asphalts at any temperature within a limited range. Conversely, the chart may be used to ascertain the temperature at which a desired viscosity is attained.

1.2 The chart is suitable for original asphalt cements and for asphalts recovered from laboratory aging tests or extracted from pavements.

1.3 The chart is based on a viscosity-temperature relationship that can be plotted using any appropriate set of units. For convenience, charts based on both conventional and SI units are provided.

1.4 The range of the chart is sufficient for roofing asphalts.

1.5 The range of the chart is sufficient for liquid asphalts (bitumens) whose viscosity exceeds 0.01 Pa.S (10 centipoise).

1.6 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in non-conformance with the standard.

2. Referenced Documents
2.1 ASTM Standards:
D341 Practice for Viscosity-Temperature Charts for Liquid Petroleum Products
D2170 Test Method for Kinematic Viscosity of Asphalts (Bitumens)
D2171 Test Method for Viscosity of Asphalts by Vacuum Capillary Viscometer
D3205 Test Method for Viscosity of Asphalt with Cone and Plate Viscometer
D4402 Test Method for Viscosity Determination of Asphalt at Elevated Temperatures Using a Rotational Viscometer
D4957 Test Method for Apparent Viscosity of Asphalt Emulsion Residues and Non-Newtonian Bitumens by Vacuum Capillary Viscometer

3. Significance and Use
3.1 The viscosity-temperature chart is a convenient means of plotting the viscosity data for estimating the viscosity of asphalts, recovered asphalts, and roofing asphalts at any temperature within a limited range. It is also a convenient means to estimate the temperature at which a desired viscosity is attained. Charts may be constructed manually or using computer graphing software.

3.2 Kinematic viscosity-temperature charts are described in Charts D341.

4. Description
4.1 For Fig. 1, the chart coordinates are logarithm of the logarithm of the viscosity in mPa.S as the ordinate, and logarithm of the absolute temperature in degrees Kelvin (degrees C + 273.2) as the abscissa. However, the viscosity in Pa.S and the temperature in degrees Celsius is shown in the chart for convenience.
(1 Pa.s = mPa.s x 10(3))

4.2 For Fig. 2, the chart coordinates are logarithm of the logarithm of the viscosity in centipoise as the ordinate, and logarithm of the absolute temperature in degrees Rankine (degrees F + 459.7) as the abscissa. However, viscosity in poise, and the temperature in degrees Fahrenheit is shown in the chart for convenience.

4.3 The temperature range of the charts may be extended or abbreviated as necessary.