The document describes the Saturation Ageing Tensile Stiffness (SATS) test, which evaluates the moisture sensitivity of asphalt mixtures. The SATS test subjects compacted asphalt samples to saturation, high temperature, high pressure, and the presence of moisture for an extended period. The retained stiffness and saturation of samples after testing are used to indicate their sensitivity to combined aging and moisture effects. The document outlines the test parameters, procedures, equipment, and findings regarding the effect of acidic versus basic aggregates on moisture sensitivity.

2. Presented By:
KHALID MEHMOOD
2K13-FT-MSC-TRAN-06
TANVEER UL HAQ
2K13-PT-MSC-TRAN-11

3. BACKGROUND:
 Moisture damage in an asphalt mixture can be
defined as the loss of strength, stiffness and
durability
 Due to the presence of moisture leading to:
 Adhesive failure at the binder–aggregate
interface
Cohesive failure within the binder or binder–
filler mastic OR pavement.

4. SATS TEST:
 The saturation ageing tensile stiffness
(SATS)
Test
is
a
combined
ageing/moisture sensitivity laboratory
test consists of initial saturation prior to
placing compacted asphalt core samples
in a high-temperature and high pressure
environment in the presence of moisture
for an extended period of time

5. CONTINUE……
 The stiffness modulus measured after
the test divided by the stiffness
modulus measured before the test
(retained stiffness modulus) and the
specimen saturation after the test
(retained saturation), are used as an
indication of the sensitivity of the
compacted mixture to combined
ageing and moisture effects.

6. DEVELOPMENT OF SATS
TEST:
 In real condition, moisture damage in
asphalt Pavement is need to have the test
methods which incorporate several sources
of damage in conditioning the tested sample
to demonstrate the real condition. An effort
towards this approach was conducted by
Collop, who developed of a combined ageing
and moisture sensitivity laboratory test for
asphalt

7. Equipment for SATS Test
 Stainless Steel Pressure Vessel (100 mm in
diameter and 65 mm thick)
 Manual Back Pressure Regulator
 600psi pressure transducer
 Temperature display module
 Balance
 Vacuum Pump

8. SATS TEST PARAMETERS
 Specimen size= (100 mm in diameter and 60 mm thick)
 Air voids = 8%
 Binder content = 4%
 Temperature = 85 °C
 Pressure = 2.1 MPa (21 bar)
 Test duration = 65 h + 24 h
 Saturation with Vacuum= 68 ± 3 kPa for 30 min.
YOUNG KYU CHOI UNI OF NOTTINGHUM

9. SATS TEST PROCEDURE:
 The
unconditioned (initial) stiffness
modulus at 20 ± 0.5°C is determined under
standard test conditions in the Nottingham
Asphalt Tester (NAT). (ITSM1).
 The dry mass of each specimen is
determined by weighing.
 The specimens are saturated under distilled
water at 20 ± 1°C, using a partial vacuum
pressure of 68 ± 3 kPa for 30 min.

10. CONTINUE……
 Remove surface water, the wet mass of each specimen
is determined by weighing, and the percentage
saturation is calculated (this is termed initial
saturation).
 The pressure vessel is partially filled with distilled
water until the level is between the fourth and fifth
specimens . The vessel and water are maintained at
the target temperature (85C) for at least 2 h before
the conditioning procedure commences.
 The saturated specimens are placed into the
vessel, using the specimen tray, and the conditioning
procedure is performed at a pressure of 2.1MPa and a
temperature of 85C for 65 h.

11. CONTINUE……
 After the test period, when the pressure
vessel display temperature has reduced to 70
°C (this may take up to 3 h), the specimens
are extracted and surface-dried. The mass is
determined by weighing, and the percentage
saturation is calculated (this is termed
retained saturation).
 The specimens are conditioned at 20
°C, and the conditioned (final) stiffness
modulus is determined under standard test
conditions in the NAT.30 (ITSM2)

12. CONTINUE……
 The final stiffness modulus divided by
the initial stiffness modulus is
calculated (this is termed retained
stiffness modulus)
 Retained stiffness= ITSM1 / ITSM2

13. RETAINED STIFFNESS VS RETAINED SATURATIONS
1
0.9
0.8
0.7
0.6
0.5
0.4
RETAINED STIFFNES (%)
0.3
0.2
0.1
0
0
10
20
30
40
50
RETAINED SATURATIONS (%)
YOUNG KYU CHOI UNI OF NOTTINGHUM
60

14. EFFECT OF ACIDIC VS BASIC
AGGREGATES
 For the mixtures containing the acidic
aggregate, the retained stiffness modulus
reduce from approximately 0·6 at a retained
saturation level of 10% to 0·2 at a retained
saturation level of between 80% and 100%.
 At a retained saturation level of 40% the
retained stiffness modulus is approximately
0·4.

15. CONTINUE……
 For the mixtures containing the basic aggregate, the
retained stiffness modulus remains at an approximately
constant value of 0·7 over a wide range of retained
saturation levels (between 15% and 80%)
 Indicating that basic aggregates have lower sensitivity to
moisture.
Collop, A.C. Development of the Saturation Ageing Tensile
Stiffness (SATS) Test

16. SATS TEST APPARATUS

17. REFRENCES:
 Collop, A.C. Development of the Saturation
Ageing Tensile Stiffness (SATS) Test. in
Proceeding of the Institution of Civil Engineers
Transport 157. 2004.
 Development of SATS Test for HMB By
YOUNG KYU CHOI
UNIVERSITY OF NOTTINGUM

18. Surface energy is the work per unit area done
by the force that creates the new surface.
Units:
•dynes per centimeter. (dyn /cm)
•Newton per meter (Nm-1)
•joule per meter square(j. m-2)
1 dyn /cm is equal to 0.001 Nm-1 or 1 mNm-1.

19. Continue…….
Typical surface energies (Source: Dr. B.R.Lawn).
material
Surface energy j. m-2
KCl
0.11
Zn
0.11
Mica
0.38
Glass
4.4
Limestone
24
Granite
200.
Fe (Cast Iron)
1520
From the table, the surface energy is very large
for Cast Iron, which is a brittle material that
shatters without much warning. Since brittle
fracture creates new surfaces, the surface energy
varies inversely with the tendency to brittle failure.

20. Surface Energy and Temperature
 In the bulk, atoms are evenly surrounded and the
cohesive forces between the atoms tend to balance.
 On the surface there are atoms on one side only, so
there is a net inward cohesive force. This creates a
force on the surface that tries to minimize its area.

21. Continue…
 When considered as a force rather than an
energy, the force is called "surface tension".
 As temperature increases, the atoms in a solid
vibrate more, and reduce the cohesive force binding
the atoms.
 The surface energy depends on the net inward
cohesive force and so surface energy decreases
with increasing temperature.

22. Measuring the surface energy
of solids
1. Fracture method:
 A crack is opened up by forces pulling the edges
apart.
 A "double cantilever" forms. The work done by the
applied force is equal to the potential energy of the
"leaf springs" and the surface energy.
Solving for the surface energy
gives:

23. Continue
2. Indentation method
 With small specimens an indentation method is used.
 A diamond point is forced into the surface and micro
cracks appear at the sharp edges.
 Measuring the lengths, a,
and c, and the indenting force, F,
will give the surface energy.

24.  Illustration of a conical indenter forced into a wafer
surface.
 Optical micrograph of an
indent introduced at room
temperature, using a conical
indenter forced into the plane
Several cracks are
initiated from the
indent.

25. 3. Angle of contact
 For a solid/liquid/gas interface, the adhesion
between the liquid and the solid will curve the liquid
surface to form a crescent type shape(meniscus).
 The angle of contact is always measured through the
liquid.

26.  FSG is the upward force between the solid and the
gas.
 FSL is the downward force between the solid and the
liquid.
 FLG is the inclined force between the liquid and the
gas.

27. If
cohesive force < adhesive force
cohesive force > adhesive force

28. Surface energy of liquids
 In dealing with liquids, it is more usual to use the
idea of Surface Tension rather than Surface
energy, even though they refer to the same
dimensional quantity. This is shown in the following
dimensional analysis.

30. 1. Capillary Action
 As a result of surface tension acting around the inner
circumference of a small-bore tube (or capillary), that
is partially immersed in a liquid, there will be a raised
or depressed column of liquid inside it.
 The upward component of the surface tension force
will balance the weight of the liquid column.

31.  The case of a raised
column is shown on the right.
 The upward component of the
surface tension force will balance
the weight of the liquid column.
 The case of a raised
column is shown on the right.
 The upward component of the
surface tension force will balance
the weight of the liquid column.

32. 2.Wilhelmy Plate Method
 A thin plate that is used to measure equilibrium
surface or interfacial tension at an air‐liquid or
liquid‐liquid interface.
 The plate is kept perpendicular to the interface and
force exerted on it is measured.
 L the wetted perimeter (2w + 2d) of the
Wilhelmy plate and θ is the contact angle between the
liquid phase and the plate.
The force on the plate due to wetting is measured via a
tensiometer or microbalance.

33. Wilhelmy Plate Method

34. 3. Pendant Drop Method
 A drop of liquid is suspended from the end of a tube
by surface tension.
 The force due to surface tension
is proportional to the length of the
boundary between the liquid and
the tube, with the proportionality
constant usually denoted γ.
 Since the length of this boundary
is the circumference of the tube, the
force due to surface tension is given by:
Fᵣ= γ
лd

35.  The mass m of the tube can be found by equating
the force due to gravity (Fg = mg) with the
component of the surface tension in the vertical
direction (Fγsinα) giving the formula
mg= лdɣ
 Where α is the angle of contact with the tube, and g
is the acceleration due to gravity.
 The limit of this formula, as α goes to 90 , gives the
maximum weight of a pendant drop for a liquid with a
given surface tension, γ

36. Pendant Drop Apparatus

37. References
Butt, H‐J.; Graf, K.; Kappl Physics
and Chemistry of Interfaces, 2nd
Edition (Wilet‐VCH: Weinheim 2006).
Gould, R.F. 1964. Contact angle
wettability and adhesion American
Chemical Society, USA.
Peter's Physics Pages Lecture 8