The document discusses several common tests used to characterize asphalt binders: 1. The penetration test measures the depth of penetration of a needle into an asphalt sample under standard conditions and was the earliest test developed in 1888. 2. The softening point test determines the temperature at which an asphalt sample can no longer support a small steel ball, indicating softening. 3. Viscosity tests measure the flow properties of asphalt at different temperatures, with absolute viscosity tested at 60°C and kinematic viscosity at 135°C, to simulate typical construction and service conditions. Standard test methods are provided for each test.

1. ‫المسم / محمود محمد رجب معروف‬
‫مسكشن/ 12‬

2. Penetration Test
the penetration test is the oldest asphalt test. In 1888, H.C.
Bowen of the Barber Asphalt Paving Company invented the
forerunner to the penetration test, the Bowen Penetration
Machine (Halstead and Welborn, 1974[1]). It’s basic principle,
and the basic principle of the penetration test, was to determine
the depth to which a truncated No. 2 sewing needle penetrated
an asphalt sample under specified conditions of load, time and
temperature. In 1915, ASTM even went as far as specifying the
brand of needle (R.J. Roberts Parabola Sharps No. 2) (Halstead
and Welborn, 1974[1]).
Basic Procedure
The current penetration test (Figure 1), first published in 1959,
describes the following basic procedure:
1.
2.
Melt and cool the asphalt binder sample under controlled
conditions.
Measure the penetration of a standard needle into the
asphalt binder sample under the following conditions:
o Load = 100 grams
o Temperature = 25° C (77° F)
o Time = 5 seconds
The depth of penetration is measured in units of 0.1 mm and
reported in penetration units (e.g., if the needle penetrates 8
mm, the asphalt penetration number is 80). Penetration Grading
is based on the penetration test.
Standard Test Methods
•
AASHTO T 49 and ASTM D 5: Penetration of
Bituminous Materials

3. Standard Test Methods
•
AASHTO T 49 and ASTM D 5: Penetration of
Bituminous Materials

4. Ring and ball Softening Point test
The softening point is defined as the temperature at which a
bitumen sample can no longer support the weight of a 3.5-g
steel ball. Although it is commonly used in Europe, it is mostly
used for roofing asphalts in the U.S. Basically, two horizontal
disks of bitumen, cast in shouldered brass rings (Figure 2), are
heated at a controlled rate in a liquid bath while each supports a
steel ball. The softening point is reported as the mean of the
temperatures at which the two disks soften enough to allow
each ball, enveloped in bitumen, to fall a distance of 25 mm
(1.0 inch) (AASHTO, 2000).
Standard Test Methods
• AASHTO T 53 and ASTM D 36: Softening Point of
Bitumen (Ring-and-Ball Apparatus)

5. Absolute Viscosity test
Asphalt binder viscosity is typically measured at 60° C (140° F)
because it approximates the maximum HMA pavement surface
temperature during summer in the U.S.
The basic absolute viscosity test measures the time it takes for a
fixed volume of asphalt binder to be drawn up through a
capillary tube by means of vacuum, under closely controlled
conditions of vacuum and temperature (ASTM, 2003 [1]).

6. Although absolute viscosity is an improvement over the
penetration test, it still only measures viscosity at one
temperature and thus does not fully characterize an asphalt
binder’s consistency over the expected range of construction
and service conditions.
Standard Test Methods
•
AASHTO T 202 and ASTM D 2171: Viscosity of
Asphalts by Vacuum Capillary Viscometer

7. Kinematic Viscosity at 135° C (275° F)
The kinematic viscosity of a liquid is the absolute (or dynamic)
viscosity divided by the density of the liquid at the temperature
of measurement. The 135° C (275° F) measurement
temperature was chosen to simulate the mixing and laydown
temperatures typically encountered in HMA pavement
construction.
The basic kinematic viscosity test measures the time it takes for
a fixed volume of asphalt binder to flow through a capillary
viscometer under closely controlled conditions of head and
temperature (ASTM, 2001).
The standard kinematic viscosity test is:
 AASHTO T 201 and ASTM D 2170: Kinematic
Viscosity of Asphalts (Bitumens)

8. ‫المراجع‬
http://www.pavementinteractive.org