This document presents a study on experimental tests conducted on bituminous mixes modified with nanoclay. The study had two phases: the first analyzed the rheological properties of modified binders compared to standard binders through tests like penetration, softening point, and dynamic shear rheometer. The second phase compared performance of modified and standard mixes through indirect tensile strength, resilient modulus, dynamic creep, and fatigue resistance tests. The results showed nanoclay modification improved rutting resistance but standard mixes performed better in fatigue resistance, especially at low temperatures.

1. A Presentation on
EXPERIMENTAL STUDIES
ON NANOCLAY MODIFIED
BITUMINOUS MIXES
SHAIK FARHEEN SULTANA
160313741401

2. CONTENTS
 INTRODUCTION
 LITERATURE REVIEW
 RESEARCH GAP
 RESEARCH OBJECTIVE
 RESEARCH SCOPE
 MATERIALS AND METHODS
 RESEARCH OUTCOMES AND SIGNIFICANCES

3. INTRODUCTION
 Bitumen used as a binder for road paving applications is a
form of liquid at high temperature and become brittle at low
temperatures which can cause high temperature rutting ,low
temperature cracking of the pavement and limits its
applications .
 About 98 percent of paved roads in India have flexible
pavements which have surfacing of Bituminous mixes with
different thicknesses.
 Physical properties and temperature susceptibility
characteristics of the bitumen influence pavement stiffness,
both at high and low field-operating temperatures, and thereby
can affect final performance of the mixture

4. INTRODUCTION
 Pavement distresses such as rutting at high temperatures can be
reduced by using modified bitumen.Addition of polymers to
bitumen is known to impart enhanced service properties such
as improved thermo mechanical resistance, elasticity and
adhesivity. But polymer modified bitumens are expensive,
difficult for operation and incompatible.Therefore further
efforts should be made for exploring new modifiers.
 Montmorillonite modified bitumen composition have been
successfully used to improve both physical and rheological
property of bitumen. It has exhibited a decreasing
penentration,an increasing softening point, a decreasing
ductility properties.

5. INTRODUCTION
 Most of roads develop distress like raveling, undulations,
rutting,cracking,bleeding,shoving of bituminous surfacing.
 Pavement performance is determined by properties of bitumen
as bitumen is a continuous phase,only deformable component ,
binding material and protective coating which plays a key role
in performance related properties of bituminous mix.
 Low temperature in winter can stiffen the binder and reduce the
flexibility of paved mix resulting in cracking and other
distresses.
 Hence modification may be necessary for better performing
bituminous mix and to solve the problem of premature failure
to some extent.

6. LITERATURE REVIEW
 Daniel Beyene Ghile,2006: Two types of nanoclay modifications were
studied ;nanofill and cloisite the study work was to conduct a comparative
test program on binders containing standard and nanoclay modified asphalts
and assess the effects of asphalt properties on pavement performances
 Lamya M. J. Mahdi1, Ratnasamy Muniandy1, Robiah Bt. Yunus2,
Salihudin Hasham1, Eltaher Aburkaba1,2013:
Two types of organic montmorillonite nanoclay (N3 and N4) were chosen
to blend with 80/100 base asphalt in various concentrations (3%, 7% and
9%) by weight of the asphalt and subjected to aging using the Rolling Thin
Film Oven in order to simulate short term aging.
 H.L.ZHAANG.J.Y.YU,L.H.XUE AND Z.L.LI,2011:Effect of
montmorillonite organic modification on microstructures and ultraviolet
aging properties of bitumen was investigated by characterising the micro
structures of MMT modified bitumen by X-ray diffraction(XRD),Fourier
transform infrared spectroscopy and atomic force microscopy.

7. LITERATURE REVIEW
 D.B.Ghile,A.A.A Molinaar,M.F.C Van De Ven,J.Besamusca:Nano
technology applied in bitumen to improve asphalt mix behavior.This paper
reported the change in rheological properties due to addition of nano clay
which helped in reducing the phase angle,increasing stiffness and reducing
the ageing of bitumen at some extent.
 S.Ghaffarpour Jahromi,N.AAhmadi,SM Mortazavi and S Vossough,2011;
Rutting and fatigue behavior of nanoclay modified bitumen.The objective of
this study was to evaluate the conventional and rheological properties of
binders containing various percentages of organic montmorillonite nanoclay
particles before and after a short-term aging process.
 Gang LIU,2011:Characterization and identification of Bituminous
materials modified with montmorillonite nanoclay .

8. RESEARCH OBJECTIVE
 The main objective of the study work is to conduct a
comparative test program on bitumen and bituminous mixes
and to evaluate the effects of montmorillonite on performance
of bituminous mixes containing standard and nano modified
bitumen.
The specific objectives of the study are:
 Study the nanoclay modifiers at nanoscale level.
 To determine the optimum dosage of montmorillonite
 Investigate and evaluate the role of different percentages of
montmorillonite modifiers in changing the rheological
properties of bitumens.

9.  Study the effect of the nanoclay modifiers on ageing
effect of the binder
 To compare the performance of montmorillonite-modified
mixes with that of plain bituminous mixes.

10. RESEARCH SCOPE
 The study comprises of nanoclay modifiers (montmorillonite)
on two types of binders (40/60, 70/100). The proportions of the
nanoclay modifiers considered in the study work are 3% and
6% in relation to the weight of the binder. Taking into account
the different test types performed, the different types and
proportions of modifiers and the different mixture types, the
overall study work done is broad and versatile.

12. METHODOLOGY
The experimental methodology consist of the following four essential phases.
Phase I: Material Collection
 Aggregate: crushed Granite coarse and fine aggregate were from collected
from quarry.
 Binder: Plain bitumen of viscosity grade 30 (VG30).
 Modifier or additive: Montmorillonite produced by market.
Phase II: Material Characterization
 Standard test such as Aggregate Crushing Strength, Impact value, Stripping
value, Los Angeles Abrasion value, Specific gravity and Combined
Elongation and Flakiness tests to characterise the aggregates.
 Standard tests such as Penetration, Softening point, Specific gravity,
Ductility and Viscosity tests to characterise the bitumen.

13. Phase III: Preparation of test specimens
 Standard Marshall Specimens.
 Compaction using standard and modified hammer.
 No of blows 75 on either side.
Phase IV: Performance Testing
 Marshall Test to assess strength of different bituminous mixes.
 Indirect Tensile Strength of conditioned and unconditioned
specimens to evaluate the rutting potential and moisture
susceptibility.

14. In this study work two phases of experimental tests are
performed and reported
In this study work two phases of experimental tests are performed
and reported.
 The first phase of the study work comprises analysis of rheological
properties of the modified binder in relation to standard binder.
The tests performed include
1. X-ray and microscopic analyses of the nanoclay
modifiers(montmorillonite)
2. Empirical rheological analysis (penetration, softening
point,ductillity test,specific gravity test)
3. Fundamental rheological properties measured with the
dynamic shear rheometer (DSR).

15.  The second phase comprises comparative tests and analyses
between modified mix and standard dense mix.
The tests performed in this phase are indirect tensile
1. strength tests at five temperature values, dynamic stiffness
tests at different temperature values
2. Fatigue resistance tests at different temperature values and
deformation at three different temperatures and three different
loading values.

16. FIRST PHASE
X-ray analysis:
X-ray analysis was performed for two main purposes being:
• 1. To know the elemental composition of the nanoclay materials
• 2. To know the chemical composition and if possible the chemical
formula of the basic molecules of the nanoclay materials
• a. Qualitative wavelength dispersive spot analyses: This test was
performed to get a qualitative analysis about the elemental
composition of the nanoclay modifiers.
• b. X-ray diffraction: This test was performed to get the chemical
composition of the compounds of the nanoclay. This is done by
determining the crystal shape of the nanoclay compounds through
the test and correlating them with close match compounds from the
library.

17. First Phase work

18. MICROSCOPIC ANALYSIS
• This test was performed to get insight on the size,
shape,arrangement and interaction of the particles of the
nanoclay modifiers at nanoscale level. The analysis was
done using an electron microprobe
Plastic analysis:
• To get an idea on the consistency of the nanoclay materials a
plastic limit test was performed on both materials

20. RHEOLOGICAL TESTS
The rheological tests done are of two types:
 i. Empirical rheological tests: These comprise the penetration
test and softening point test,ductility test
 ii. Fundamental rheological tests: These comprise tests with the
DSR, Rotating Cylindrical Ageing Tester (RCAT),PAV.
 iii.And then it is followed by penetration and softening point
computations by comparing modified and standard bitumen.

21. EMPERICAL RHEOLOGICAL TESTS
PENETRATION TEST
• Penetration tests determines the hardness or softness of bitumen by
measuring the depth in tenths of a millimeter to which a standard loaded
needle will penetrate vertically in five seconds at a temperature of 25°C.
• The penetration test determines the consistency of bitumen for purpose of
grading. The softer the bitumen, the greater will be the penetration value.
SOFTENING POINT TEST
 The softening point is the temperature at which the substance attains
particular degree of softening under specified condition of test.
 Generally higher softening point indicates lower temperature susceptibility
and is preferred in warm climates. Hard grade bitumen possesses higher
softening point than soft grade bitumen

22. DUCTILITY TEST
Ductility test gives a measure of adhesive property of bitumen
and its ability to stretch.
As the binders form ductile thin films around the aggregates, a
certain minimum ductility is necessary for a binder to
withstand the temperature changes in mixes and the repeated
deformations that occur due to the traffic loads.

23. DSR
The discussion on DSR test results comprises the following areas:
A typical DSR test results analysis which comprises :
 frequency sweep analysis;
 master curve and black diagram.
 Comparison of the master curves of the stiffness of the
modified and unmodified binders.
 Comparison of the master curves of phase angles of the
modified and unmodified binders.
 Analysis of the change in ageing effect of the binder due to the
modification.
 Analysis of the rutting and fatigue resistance parameters for
the modified and unmodified binders.

24. Frequency sweep DSR test results
 The frequency sweep results can be used in the construction of
master curves and black diagrams
Master curve of stiffness and phase angle
 Construction of mater curves of stiffness and phase angle is of great
significance because:
 it can describe rheological properties of bitumen under a wide range
of loading frequencies for a selected temperature value;
 a comparison of stiffness and phase angle values of the modified and
unmodified binders is better described by master curve values than
frequency sweep results;
 an effect of modification on the ageing effect of the binder can also
be better explained and clarified using master curve values than the
frequency sweep results.

25. BLACK DIAGRAM
 The black diagram relates the complex modulus with the phase
angle value and is unique for a selected binder type. The black
diagram is seen as a fingerprint of the binder. It can tell us how
the two values are related under wide temperature ranges
SHORT TERM AGEING EFFECT ANALYSIS
 The short term ageing effect analysis is performed based on the
master curves of the stiffness and phase angle values

30. PREPARATION OF SPECIMEN
CHARACTERIZATION OF AGGREGATES
 In order to access the suitability of the aggregate for road
construction, the mechanical and physical properties of
aggregates are tested in laboratory.
 Crushing value
 los angles abrasion value,
 impact value,
 specific gravity of course and fine aggregate,
 combined elongation and flakiness index

31. MARSHALL STABILITY TEST
 The Marshall stability of the mix is defined as the maximum
load carried by the specimen at a standard test temperature of
60 degree Celsius the temperature which represents the
weakest condition for a bituminous pavement in use.
The steps involved in this test are
• Mixing
• Compaction
• Mix properties

32. MIXING PROCESS
 The coarse and fine aggregate were taken in the specified
proportions so as to produce compacted bituminous mix specimens
of thickness 63.5mm approximately and the weighed quantity of
bitumen corresponding to each percentage was added to the heated
aggregate and thoroughly mixed at the specified mixing temperature,
using a mechanical mixer.
COMPACTION METHOD
 To evaluate the effect of compaction on mix properties two types of
compaction methods were adopted. Standard Marshall Compaction
and modified Marshall Compaction efforts were analyzed by
comparing the volumetric properties and performance parameters of
mixes prepared with different types of compaction hammers

33. MIXING PROPERTIES
The important properties of the mix are
 theoretical specific gravity(Gt)
 the bulk specific gravity of the mix(Gm)
 percent air voids(Vv)
 percent volume of bitumen(Vb)
 percent voids in mineral aggregate(VMA) and
 percent voids filled with bitumen(VFB)

34. SECOND PHASE
Tests are to be performed on modified and standard dense
bituminous mixtures and the comparison of the test results to
see the effect of the clay modification on the performance of
the asphalt mixtures.
The performance tests selected for comparison are:
 i. Indirect tensile strength test
 ii. Resilient modulus test
 iii. Dynamic creep test
 iv. Fatigue resistance test

35. DYNAMIC CREEP TEST
Dynamic creep test is performed to:
 determine the resistance to permanent deformation of the standard
and modified dense mixtures at high temperatures and make a
comparative analysis;
 investigate the effect of variation of temperature and level of applied
pressure on the permanent deformation resistance response of the
modified and standard dense mixes.
INDIRECT TENSILE STRENGTH discusses on:
 Test result analysis and comparison of indirect tensile strength
values of the modified and unmodified dense asphalt mixtures;
 comparison of the fracture energy of the modified and unmodified
asphalt mixtures

36. RESILIENT MODULUS TEST
The resilient modulus test is performed to :
 Determine the elastic moduli of the modified and standard dense
mixtures and develop master curves for each mix;
 Make a comparative analysis of resilient modulus values between
the standard and modified dense mixtures.
FATIGUS RESISTANCE TEST
 Fatigue resistance test is performed to determine the fatigue
resistance of the standard and modified dense mixtures at
different test temperatures and loading conditions and
 to make a comparative analysis of their fatigue resistance.

38. MODELS USED IN THE STUDY ARE
 Using regression analysis, fatigue equations were developed.
The linear regression models of fatigue life (Nf) with resilient
modulus (Mr) are developed and Linear Regression equation
between Fatigue life (Nf) and Initial strain (Ɛ)
 ANOVA analysis was done between the fatigue life of the
control with nano-modified mixes at 5% binder content for
VG30. The null hypothesis is their means are equal and the
alternative hypothesis is their means are not equal.

39. OUTCOME
• From the previous studies Tests performed on binders and
dense asphalt mixtures proved that the nanoclay modifications
helped to increase the stiffness, to improve the rutting
resistance of the standard 40/60 binder.
 In addition, the indirect tensile strength and fracture energy
values are increased due to modification.
 The nanofill modification helps to improve the ageing
resistance of the 70/100 binder in the short term and long term
too.
 However, when it comes to fatigue resistance performance, the
standard binders/mixtures were performing better than the
nanoclay modified binders /mixtures especially at low test
temperatures.

40. REFERENCES
 ASTM D5581 (1996). “Resistance to plastic flow of bituminous mixes
using Marshall Apparatus”.
 ASTM D6931 (2007). “Standard Test Method for Indirect Tensile (IDT)
Strength of Bituminous Mixes
 Fundamental Characterization of Asphalt Clay Nano-Composites
 Dr. John Read and Mr. David Whiteoak, 2003, The Shell Bitumen Hand
book, UK
 NCHRP report 459, 2001, characterization of modified asphalt binders in
superpave mix design, Washington D.C.
 TRB report number 1454, 1994, Asphalt concrete mixture design and
performance,Washington D.C.
 TRB report number 1590, 1997, Asphalt mixture quality characteristics and
performance, Washington D.C.

41. REFERENCES
 TRB report number 1789, 2002, bituminous paving mixtures materials and
construction,Washington D.C.
 TRB report number 1832, 2003, bituminous paving mixtures, Washington
D.C.
 TRB report number 1488, 1995, unmodified and modified asphalt binders,
WashingtonD.C
 D.B Ghile, A.A.A. Molenaar, M.F.C. van de ven, J. Besamusca, CROW
conference WW2006, Nanotechnology applied to bitumen to improve
asphalt mixture behavior Doorwerth, The Netherlands
 Prf.dr.A.A.A. Molenaar, D.B Ghile, Ir.M.F.C. van de ven ,December 2005,
report number 7-04-110-25, CROW report, Effect of nano-clay modification
on rheology of bitumen ,The Netherlands