moisture damage

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					       Journal of Transportation Engineering. Submitted December 17, 2010; accepted June 7, 2011;
             posted ahead of print June 10, 2011. doi:10.1061/(ASCE)TE.1943-5436.0000306


       LABORATORY STUDY ON MOISTURE SUSCEPTIBILITY
                 OF DENSE GRADED MIXES
                                   Dr Praveen Kumar* and P. Anand**
                                               ABSTRACT
Moisture damage is the degradation of the mechanical properties of the material due to the

presence of moisture in its microstructure. To enhance the life of bituminous pavements, it is




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inevitable to understand moisture‟s damage on pavements and to evaluate the effects of hydrated

lime as moisture damage resisting agents. The basis of laboratory work was AASHTO T 283 test




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and it was performed on two types of dense graded bituminous mixes which included Dense




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Bituminous Macadam and Bituminous Concrete mix. The study was carried out for mixes




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prepared without lime and the same process was repeated with addition of 2% quantity of
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hydrated lime. The quantity of lime was decided on the basis of guidelines given in IRC: 111-
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2009. The addition of hydrated lime in the asphalt mix improves the tensile strength ratio.

However, a well-controlled lime treatment is required to maximize distribution and dispersion of
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lime particles on aggregate surfaces.

             This study also presents various causes of moisture damage and their mechanisms.
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Attention is also given to the chemical and mineralogical composition of aggregates and effect of
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some important minerals on moisture susceptibility of aggregates.
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Keywords: moisture damage, asphalt mixtures, mechanisms, hydrated lime, tensile strength

ratio, stripping, mineralogical.



   *     Professor, Civil Engineering Department, Indian Institute of Technology, Roorkee India

   ** M.Tech. Student, Civil Engineering Department, Indian Institute of Technology, Roorkee

   India


                                                   1

                        Copyright 2011 by the American Society of Civil Engineers
     Journal of Transportation Engineering. Submitted December 17, 2010; accepted June 7, 2011;
           posted ahead of print June 10, 2011. doi:10.1061/(ASCE)TE.1943-5436.0000306




INTRODUCTION

In India, approximately 98 percent roads are flexible types probably because of economy. There

are two million miles of paved roadways in India. The Hot Mix asphalt (HMA) is used on

approximately 98 percent of all paved surfaces. Over time, the existing highway system has been




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taxed due to an increased level of demand.     Due to increased demand from additional and




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heavier traffic lack of resources for additional roadways, and user expectations regarding safety,

HMA pavements must perform well for longer periods of time, especially in light of budget




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shortfalls to cover estimated costs for necessary development. These roads have a dismal record

on performance and durability despite of elaborate standards and specifications availability.
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These roads are susceptible to deterioration mainly due to reasons like stripping of pavements.
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This highlights the need for experimental methods that can evaluate the asphalt mixture

components and analysis procedures that reliably predict performance expectations under
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varying moisture-conditioning scenarios.
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BITUMEN AND AGGREGATES ADHESION
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One of the principal functions of a bituminous binder is to act as an adhesive either between

aggregates or between aggregates and the underlying road surface. The adhesion of bituminous
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binder to aggregates presents few problems in the absence of water, although the excessive dust

may create trouble. On the other hand, because of aggregates are wetted more easily by water

than by a bituminous binder, the presence of water can lead to difficulties, either in the initial

coating of dry or wet aggregates or in maintaining an adequate bond between the binder and the

stone. Failure of a bond already formed is called stripping, which is brought about by the

displacement of the bituminous binder from the stone surface of water.


                                                 2

                      Copyright 2011 by the American Society of Civil Engineers
     Journal of Transportation Engineering. Submitted December 17, 2010; accepted June 7, 2011;
           posted ahead of print June 10, 2011. doi:10.1061/(ASCE)TE.1943-5436.0000306


Influence of Aggregate on Stripping

There are number of factors that influence the asphalt–aggregate bond such as surface

texture, penetration of pores and cracks with asphalt, aggregate angularity, aging of the

aggregate surface through environmental effects, adsorbed coatings on the surface of the

aggregate, chemical and mineralogical composition of aggregates and the nature of dry




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aggregates versus wet aggregates. Surface texture of the aggregate affects its ability to be




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properly coated, and a good initial coating is necessary to prevent stripping. Cheng, et al.,

(2002) demonstrated that the adhesive bond, calculated from basic surface energy




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measurements of the asphalt and aggregate, between certain granites and asphalt was higher

than between limestone aggregate and asphalt when the bond was quantified as energy per
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unit of surface area. However, when the bond was quantified as energy per unit of aggregate
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mass, the bond energy was far greater for the calcareous aggregates than for the siliceous.

Besides the importance of a good mechanical bond promoted by the surface texture,
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stripping has been determined to be more severe in angular aggregates because the angularity

may promote bond rupture of the binder or mastic by leaving a point of intrusion for the
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water. Cheng, et al., (2002) substantiated this as they have shown that, regardless of the
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strength of the bond between the asphalt and aggregate, the bond between water and
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aggregate is considerably stronger. There is some evidence that moisture damage can be

minimal if stripping is restricted only to the coarse aggregate. If the fine aggregate strips,

severe damage can occur because the fine aggregate constitutes the basic matrix of the

mixture.

VOID STRUCTURE AND MOISTURE DAMAGE CONCEPT




                                                 3

                      Copyright 2011 by the American Society of Civil Engineers
     Journal of Transportation Engineering. Submitted December 17, 2010; accepted June 7, 2011;
           posted ahead of print June 10, 2011. doi:10.1061/(ASCE)TE.1943-5436.0000306


Moisture transport in a porous medium such as asphalt mixtures is influenced by the void

structure. Therefore, in order to identify the modes of moisture transport and their

relationship to moisture damage, it is important to characterize the void structure in asphalt

mixtures. Some transportation agencies attempt to control moisture damage by limiting the

percent of air voids. Air voids in surface asphalt courses must be as low as possible in order




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to control moisture damage (Mohamed et al., 1993). Nevertheless, even with a low




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percentage of air voids, there is evidence of damage produced by infiltration of water which

proves that total air void content does not provide a comprehensive measure of the rate of




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moisture transport in asphalt mixtures. The size and distribution of air voids in asphalt

mixtures depend mainly on the aggregate properties, mix design and compaction processes.
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Chen et al., (2004) classified air voids in asphalt mixtures into three categories: effective,
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semi-effective and impermeable. However, the identification of these different types of air

voids in laboratory or field samples is difficult because of the complex internal structure of
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the material and the limited ability to explore its interior composition. There are various

alternatives to determine the void structure of porous specimens. Some common techniques
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make use of two dimensional images of the cross sections of the material acquired by
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scanning electron microscopy, spectroscopic imaging techniques (to determine the chemical
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composition)   and    atomic    force   microscopy.     Techniques    for   three   dimensional

characterizations of porous media include nuclear magnetic resonance (NMR) imaging,

transmission electron microscopy visualization and X-ray computed tomography (CT)

reconstruction. X-ray CT is a non-invasive technique that has gained wide acceptance in the

past few years. This technique has been successfully used to characterize the microstructure

of porous materials such as solid foam textiles, pharmaceutical granules, biological materials



                                                 4

                      Copyright 2011 by the American Society of Civil Engineers
     Journal of Transportation Engineering. Submitted December 17, 2010; accepted June 7, 2011;
           posted ahead of print June 10, 2011. doi:10.1061/(ASCE)TE.1943-5436.0000306


and asphalt mixtures. Image analysis can be used to determine the void structure of the

material. This non-destructive procedure has three main advantages:

        It allows probabilistic determination of the air voids by measuring the size of individual voids.

It allows the determination of potential paths for moisture transport by identifying interconnected air

voids between different sections. It can be used to compute the ratio of the true length of a path to the




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length of the straight line between its ends.




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        Further, most of the regular dense graded asphalt mixtures are designed with an air

void content in the range of 5 – 10 percent, which is the most likely range for the average




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size air voids. Shanmugasundaram (Indian Highways, Sept 2005) during laboratory mix

design recommends 3 to 5 percent of air voids. This range is the level desired after several
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years of traffic. Since traffic also consolidates the pavement to certain degree, this level will
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be achieved, if the percent air voids after construction is about 8 percent. If the final air void

content is more than 5 percent or if the pavement is constructed with more than 8 percent air
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voids initially, then moisture will enter in due course which makes bituminous film brittle

and develops cracks. If the final air void content is less than 3 percent, the expansion of
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bitumen during summer season develops bursting stresses and premature fine cracks form on
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the pavement surface. Air void content below 3 percent greatly increases the probability of
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premature rutting. It is also important to mention that factors related to construction such as

mixture production, placement and compaction also affect the void structure of asphalt

mixtures in the field. For example, Mohamed et al., (1993) found that common compaction

techniques in asphalt layers generate cracks, commonly known as checks. These cracks are 1

– 3 inch apart. Checks are normally not visible and are generated during the first or second

pass of conventional steel-wheel rollers. Cracks act as links between air voids, generating



                                                      5

                        Copyright 2011 by the American Society of Civil Engineers
     Journal of Transportation Engineering. Submitted December 17, 2010; accepted June 7, 2011;
           posted ahead of print June 10, 2011. doi:10.1061/(ASCE)TE.1943-5436.0000306


new connected paths. Studies have also been carried out to analyze the effect of lift thickness

and other construction characteristics in the void structure of asphalt courses (Mohamed et

al., 1993). The image analysis techniques can be used to characterize the air void structure of

asphalt mixtures prepared in the laboratory or of field cores.

Modes of Moisture Transport




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Most of the research pertaining to moisture damage assumes the presence of water in the




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material. Therefore, the modes by which moisture reaches the mixture have usually been

overlooked. The three main modes of moisture transport are:-




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Infiltration of surface water,

Capillary rise of subsurface water and
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Permeation or diffusion of water vapor.
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        Infiltration of water from the surface is the main source of moisture in the pavement

and is directly related to rainfall, drainage conditions and material properties. The main
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modes of moisture transport in asphalt mixtures are:-

        Water permeability.
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        Water capillary rise.
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         Vapor diffusion.
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Aggregate – Binder Interface

Moisture in asphalt mixtures generates the cracks in the material. Crack growth in asphalt

mixtures can occur either within the binder or at the binder – aggregate interface. The former

is referred to as cohesive cracking, and the latter is referred to as adhesive cracking.

Typically, adhesive failure will occur if asphalt binder film is very thin and cohesive failure

will occur if it is very thick. Compared to cohesive bonds, adhesive bonds are considered to



                                                  6

                       Copyright 2011 by the American Society of Civil Engineers
     Journal of Transportation Engineering. Submitted December 17, 2010; accepted June 7, 2011;
           posted ahead of print June 10, 2011. doi:10.1061/(ASCE)TE.1943-5436.0000306


play a more important role in moisture damage manifested as stripping of the binder from the

aggregate. Three types of interaction forces are responsible for adhesion between the asphalt

binders and aggregate. The first type corresponds to electrostatic interactions between ions

and refers to forces between two separated charges, resulting from Coulomb‟s inverse-square

law (i.e. Coulomb forces). The second type corresponds to electrodynamics interactions




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through Vander Waal forces. The third type corresponds to interactions through electron pair




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sharing (i.e. covalent bond). In this case, the bonds result from the union of two components

when sharing an electron pair. The electrostatic and     electrodynamics      interactions   are




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regarded as physico – chemical bonds, and the interactions in the last group are regarded as

chemical bonds. Experimental techniques can quantify the susceptibility of adhesive bonds
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between the asphalt binder and aggregate to moisture damage. Huang et al., (2005) presented
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a comprehensive evaluation of several techniques to analyze the aggregate – binder

interface system. The authors analyzed the validity, limitations and potential of five
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techniques using eight binders (Strategic Highway Research Program (SHRP) core asphalts)

and some commonly used aggregates. The techniques evaluated included a sliding plate
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Rheometer, differential scanning calorimetric, liquid chromatography, centrifugation and
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infrared spectroscopy. The authors found that all techniques are rapid procedures that
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provide valuable information about interactions occurring at the interface of the asphalt

binder with the aggregate (also recognized as a thin-film phenomenon). These techniques

are supported by theories that explain adhesive bond mechanisms and are described below

(Hicks, 1991, Little and Jones, 2003).

Weak Boundary Layers




                                                 7

                      Copyright 2011 by the American Society of Civil Engineers
     Journal of Transportation Engineering. Submitted December 17, 2010; accepted June 7, 2011;
           posted ahead of print June 10, 2011. doi:10.1061/(ASCE)TE.1943-5436.0000306


The theory suggests that rupture always takes place at the weakest link        found     at     the

interface between materials. These defects at the interface are possible because of poor

wetting, the presence of voids and dust at the interface. This theory does not explain why

materials adhere to one another but rather adhesive bonds fail in either the adhesive or

substrate due to the presence of an interface region of low cohesive strength.




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Electrostatic Forces




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The electrostatic theory attributes the adhesive strength between two materials to the Columbic




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forces of attraction at the surface of the materials. Interactions between solid surfaces and liquid




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media containing dissolved ions, such as water, are particularly important to explain moisture

damage in asphalt mixtures.
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Chemical Bonding
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Research on adhesion due to chemical bonding is important in explaining the moisture
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damage mechanisms in some aggregate – binder systems. Chemical bonding theory suggests

that the adhesive bond between the asphalt binder and aggregate results from a chemical
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reaction between two materials. Bonding between two materials due to their surface free
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energy or electrostatic interactions is also based on the chemical nature of these materials.

Mechanical Interlock Theory
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Mechanical theory describes the most intuitive adhesion        phenomenon          and   traditionally

involves mechanical gripping of the adhesive into the cavities,        pores and asperities of the

solid surface on a macroscopic scale. After an initial rapid wetting, the filling of micro voids by

the liquid takes place, followed by its solidification. The resulting interlocking combines the

cohesive strength of both individual solids to form an interface that acts as a composite material




                                                  8

                       Copyright 2011 by the American Society of Civil Engineers
     Journal of Transportation Engineering. Submitted December 17, 2010; accepted June 7, 2011;
           posted ahead of print June 10, 2011. doi:10.1061/(ASCE)TE.1943-5436.0000306


with properties intermediate to those of each material surface. Such a lock and key mechanism of

bonding can explain the good resistance of some bonds to water damage.

Adsorption Theory

The theory can be applied to the vast majority of adhesion and adsorption phenomena of liquids

onto solids. Thermodynamic theory is based on the concept that an adhesive will adhere to a




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substrate due to established intermolecular forces at the interface provided intimate contact is




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achieved. The magnitude of these fundamental forces can generally be related to thermodynamic




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quantities, such as surface free energies of the materials involved in the adhesive bond. It




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describes wetting phenomena and is based on the measurement of the contact angle between a

liquid and a solid.
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Chemical and Mineralogical Composition of Aggregate
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Aggregates constitute the biggest part of the mixture (over 94% by weight) and provide a
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surface onto which the bitumen/mastic adheres. The resistance of adhesive bonding to

stripping relates to aspects of the aggregate like surface charge, polarity, porosity, type of

adsorption sites and surface energy, which are directly determined by the minerals and
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chemical elements present in the aggregates. Consequently, aggregate composition probably

influences resistance to moisture damage. The sticking of bitumen onto an aggregate and its
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replacement by moisture depends partly on interaction of the polar groups at the interface

and interfacial Vander Waals forces, e.g. Keelson orientation forces, Debye induction forces

and London dispersion forces (Curtis et al. 1993). Some of these forces depend on the type

and magnitudes of aggregate surface charges, which themselves depend on the nature of

minerals and metallic ions present. Martens and Wright (1959) adequately describe the

mechanisms leading to the presence of polar components on aggregate surfaces. Aggregate


                                                 9

                      Copyright 2011 by the American Society of Civil Engineers
     Journal of Transportation Engineering. Submitted December 17, 2010; accepted June 7, 2011;
           posted ahead of print June 10, 2011. doi:10.1061/(ASCE)TE.1943-5436.0000306


surfaces may also have broken bonds that result from a break in coordination bonds holding

together the aggregate atomic crystal lattices. This break in bonds happens during quarrying

and crushing. Water or other contaminants in the air can be attracted to the fresh surfaces to

satisfy broken bonds. Since water is normally available, the driving force for the adsorption

of water on the freshly crushed aggregate faces is that it reduces the free energy of the




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system. These processes seem to relate to aggregate mineralogy. The common minerals in




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aggregates include silica, feldspars, carbonates and clays (Roberts et. al., 1991).Silica

mineral (SiO2) abundant in quartz constitute the bulk of quartzite and granite. During




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quarrying, unsatisfied charges form by breaking the silicon–oxygen bonds. Hydration occurs

when water vapor releases OH- and H+ ions to the unsatisfied charges on silicon and oxygen,
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respectively. This results in a hydroxyl Ted surface with surface silanol groups. Equilibrium
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is established between these silanols and water depending on the pH of the contact water.

Water with a high pH (OH - ions) stimulates the dissociation of H+ ions from silanol groups
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causing the surface to become more negatively charged. At low water pH, silica surfaces

become positively charged. Water molecules can form strong hydrogen bonds with siliceous
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surface silanols which may cause replacement of the bitumen polar parts. Feldspar minerals
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have mobile species within their crystal structures (Jones et al. 2004). For example,
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orthoclase (KAlSi3O8), albite (NaAlSi3O8) and anorthite (CaAl2Si2O8) have alkaline earth

metals like potassium, sodium and calcium, respectively, as their mobile species. Other

minerals with such metallic elements include olivine (Mg,Fe) 2SiO4 and augite

(Ca,Mg,Fe)(Si,Al)2)6. The nature of interaction between these metallic elements and the

bitumen components determines the sensitivity of adhesion to moisture. Limestone mainly

comprises CaCO3, which after crushing exposes electropositive surface characteristics. This



                                                 10

                      Copyright 2011 by the American Society of Civil Engineers
     Journal of Transportation Engineering. Submitted December 17, 2010; accepted June 7, 2011;
           posted ahead of print June 10, 2011. doi:10.1061/(ASCE)TE.1943-5436.0000306


is because its interior bonds are broken leaving calcium and carbonate ions on the newly

formed surfaces. Hydration of these ions by water vapor, results in a characteristic

electropositive surface. These surface species are available for competition between water

and bitumen polar functionalities. Clay minerals acquire charges from structural

imperfections due to ionic isomorphous substitution. Depending on the valences of the




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substituting and substituted cations, a net negative or positive charge may result on the clay.




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Hydroxyl groups present on the edges of clay structures may lead to a pH             dependent

charge in the presence of water. Micas like biotite [K (Mg, Fe 2+)3 (Al,Fe3+)Si3 O10




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(OH)2] may be poor adherents. Micas are also friable and this might lead to premature

damage in presence of water. When moisture enters the interface, its molecules being more
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polar, can often be more strongly adsorbed on the aggregate surface than the bitumen
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component, thus displacing it. There can be cases where ionic bonds between bituminous

carboxylic acids and metallic ions like calcium in the mineral surface (e.g. limestone) may
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not be affected by water. It has been found that carboxylic acids in the bitumen were strongly

adsorbed on siliceous aggregates, but were present in very small amounts. At the same time,
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carboxylic acids tend to be displaced first from the aggregate in presence of moisture. This
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background on previous fundamental research underlines the dependence of moisture
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sensitivity on aggregate composition. While the influence of moisture damage on pavement

performance and maintenance costs is not clearly defined, the global upsurge in use of anti

stripping additives and the use of many different moisture sensitivity tests shows that

moisture damage is still an important issue.

Stripping Mechanism

Moisture-related problems are accelerated by:-



                                                 11

                      Copyright 2011 by the American Society of Civil Engineers
     Journal of Transportation Engineering. Submitted December 17, 2010; accepted June 7, 2011;
           posted ahead of print June 10, 2011. doi:10.1061/(ASCE)TE.1943-5436.0000306


Adhesive Failure: Stripping of the asphalt film from the aggregate surface.

Cohesive Failure: Loss of mixture stiffness.

       Adhesive failure in aggregates and asphalt occurs at an interface, while cohesive

failure occurs directly within asphalt. These mechanisms can be associated with the

aggregate, the binder, or the interaction between the two ingredients. Stripping usually




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begins at the bottom of the HMA layer, and travels upward.           A typical situation is       a




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gradual loss of strength over a period of years, which allows rutting and shoving to develop

in the wheel path.




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LABORATORY WORK AND ANALYSIS

 The foremost function of this laboratory work is to verify the stripping potential of
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different type of aggregates having different chemical and mineralogical composition using
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AASHTO T 283 and ASTM D 1075-54 tests. These tests were performed on compacted

bituminous mixture of Dense Bituminous Macadam (DBM) and Bituminous Concrete (BC).
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Marshall Stability method has been used to determine the optimum bitumen content (OBC). The

Marshall samples were prepared using VG 30 grade bitumen and different type of aggregate. The
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mixing temperature was in the range of 150 to 170° C. The compaction temperature was
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maintained at minimum 90° C.
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Procedure Followed for Laboratory Test

The procedure followed for laboratory work involved in this project is categorized in Figure 1.

The aggregates used in the study mainly belonged to the category of quartzite, granite,

limestone and sandstone. Quartzite is abundantly available in many parts of the country;

therefore two type of quartzite with different composition was used. These stones were

procured from Hardwar and Delhi. Granite was procured from Lucknow and it exits in



                                                 12

                      Copyright 2011 by the American Society of Civil Engineers
      Journal of Transportation Engineering. Submitted December 17, 2010; accepted June 7, 2011;
            posted ahead of print June 10, 2011. doi:10.1061/(ASCE)TE.1943-5436.0000306


granite reserves of Jhansi Bundelkhand region. Limestone was procured from Dehradun and

sandstone was procured from Phalaudi region of Jodhpur. The limestone used was dark grey

in color and to some extent resembles the quartzite procured from Delhi region. Therefore the

limestone was treated with concentrated acid in the laboratory, on testing it released heavy

amount of carbon dioxide, which confirmed high content of calcium.




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    Initially, Marshall samples of each type of aggregate were prepared without lime and




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aggregates susceptibility to moisture was assessed. Later, same procedure was repeated with

addition of 2% lime as per IRC 111-2009 and improvement in resistance to moisture was




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determined. Types of aggregates and their place of origin are shown in Table 1.

        The bitumen used in the study was VG-30 grade bitumen which was characterized for
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physical properties and these values were compared with specified values as per BIS 73-2001
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specifications. Similarly all five types of aggregates and anti stripping agent were

characterized for their physical properties and gradation requirements as per IRC: 111- 2009.
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The first four types of aggregates given in table 1 met the criteria for both the mixes of DBM

and BC but aggregate at serial no. „E‟ satisfied the requirements for DBM mix only. The
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gradation of selected component aggregates and their proportioning was achieved by trial and
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error method.
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Determination of OBC Using Marshall Stability Method

Optimum bitumen content was determined using Marshall stability and flow method.

Aggregate Grading and Bitumen Content are presented in Table 2. Reuirement of the Dense

graded Bituminous Mix are given in Table 3.

        From the table 4, it can be seen that for aggregates with specific gravity more than 2.7,

bitumen content reduces below the minimum limit of 4.5% as in case of Delhi quartzite,



                                                  13

                       Copyright 2011 by the American Society of Civil Engineers
     Journal of Transportation Engineering. Submitted December 17, 2010; accepted June 7, 2011;
           posted ahead of print June 10, 2011. doi:10.1061/(ASCE)TE.1943-5436.0000306


whereas in case of limestone and sandstone bitumen content is above 4.5% despite specific

gravity value being more than 2.7. From visual inspection, it was observed that limestone and

sandstone aggregates fineness was more than Delhi quartzite therefore it indicates that bitumen

content value also depends on fineness of coarse aggregate.

       Also, from volumetric properties summary, it is concluded that with addition of lime in




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the mix, air voids content reduces but stays within the prescribed limit of 3-5%which is




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necessary for drainage of water. OBC of all BC mixes prepared with and without lime was

within the range prescribed in IRC: 111-2009.




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Aggregate Characterization Tests

       The aggregates were characterized based on chemical and mineralogical composition and
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testing procedure is described in detail below:
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   Contents of potassium, sodium, iron, magnesium, calcium and manganese are determined by

    digesting 200 mg of aggregate samples, ground to minus 100 mesh sieve, with 10 ml of
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    hydrofluoric acid (conc.40%) reagent mixed with 3 ml of perchloric acid (conc.70%).

   The mixture of the acids and the sample was heated in a 50 ml beaker for 1 h on a hot plate
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    having a surface temperature of 200o C and then allowed to cool at room temperature for five
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    minutes.
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   The resulting solution was diluted with distilled water, filtered and analyzed using an atomic

    absorption spectrophotometer (AAS). The chemical analysis of aggregates is given in table 5.

MOISTURE SUSCEPTIBILITY TESTS

       The moisture susceptibility tests were performed on loose and compacted bituminous

mixtures to assess aggregates potential to resist stripping. The following two tests were

conducted to determine the potential of HMA mixture to stripping and their results are shown in



                                                  14

                      Copyright 2011 by the American Society of Civil Engineers
     Journal of Transportation Engineering. Submitted December 17, 2010; accepted June 7, 2011;
           posted ahead of print June 10, 2011. doi:10.1061/(ASCE)TE.1943-5436.0000306


tables below:-

Test on loose or uncompacted mixtures

       10 min boiling water test (ASTM D 3625-91)

Test on compacted specimens

       Effect of Water on Cohesion of Compacted Bituminous Mixes (ASTM D 1075-54)




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       Resistance of Compacted Asphalt Mixtures to Moisture Damage (AASHTO T283)




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The results of these tests are given in Tables 6 to 12.

Limestone




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It was observed during the vacuum saturation that Marshall Samples prepared with limestone

aggregate comparatively took more time than other type of aggregates. In case of granite,
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sandstone and quartzite the time taken for vacuum saturation of samples was 25-30 min to
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achieve a saturation level of 55- 70% where as in case of limestone the time taken was 50-60 min

to achieve the same level of saturation.
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Retained Marshall Stability DBM Mix with and without Lime (ASTM D 1075 -54)
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From table 7, it can be seen that all the surfaces have more than required values of retained
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Marshall Stability for DBM mixes prepared without the use of anti stripping agent i.e. lime.

These values are ranging from 80.2% to 87.9%. These values further get improved by 8-12% in
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all the aggregates on addition of 2% quantity of lime. In case of limestone, the mix was prepared

without the use of lime content and retained Marshall Stability value obtained is 98.8%.

Retained Marshall Stability of BC Mix with and without Lime (ASTM D 1075 -54)


From the table 7, it can be seen that all the surfaces have more than required values of retained

Marshall Stability for BC mix prepared without the use of anti stripping agent lime. These values

are ranging from 86.5% to 89.1%. These values further get improved by 8-10% in all the cases

                                                 15

                      Copyright 2011 by the American Society of Civil Engineers
       Journal of Transportation Engineering. Submitted December 17, 2010; accepted June 7, 2011;
             posted ahead of print June 10, 2011. doi:10.1061/(ASCE)TE.1943-5436.0000306


on addition of 2% quantity of lime. In case of limestone, the mix was prepared without the use of

lime content and retained Marshall Stability value obtained is 98%. The Delhi quartzite was not

tested for BC mix since its impact value did not meet the design criteria of BC mix laid down by

Ministry of Road Transport and Highways (MoRTH) specifications.

Tensile Strength Ratio of DBM and BC Mixes with and without Lime (AASHTO T 283)




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Tables 8 to 12 compare the TSR for samples with and without anti-stripping agent for two




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conditioning methods. The results of the AASHTO T 283 mixes demonstrate that two of the




           te s
mixes for DBM do not meet MoRTH criteria even on addition of 2% lime in the mix. Although,




         di nu
two of the mixes failed the TSR requirement as tested during this study, but there are two mixes

whose TSR values were less than the prescribed limit but improved to meet the prescribed
       ye a
criteria on addition of 2% lime. Limestone mix was tested without the use of anti strip agent and
     op M
successfully met the standards, which indicates high content of CaCO3 in it.
   C ted


         The results of the AASHTO T 283 mixes demonstrate that out of four mixes tested for

 BC, three of the mixes could not meet the prescribed value of 80% but ultimately met the
 ot p



 prescribed criteria on addition of 2% lime. Lime acts as Water proofing agent and after
N ce




 addition of lime, the mixes responded favorably. Lime stone mix was tested without the use of

 anti strip agent and successfully met the standards, which indicates high content of CaCO 3 in
  Ac




 it.

Aggregate Washing and Mixing of Lime

After analyzing the AASHTO T283 results, the granite aggregate was washed with water and

dried in oven at a temperature of 135oC to 145oC for one hour. This aggregate was used for the

preparation of DBM mix without the use of lime and AASHTO T 283 test was reconducted.

With mere washing of granite aggregate, the value of TSR increased from 70% to 72.9%.The

                                                   16

                        Copyright 2011 by the American Society of Civil Engineers
     Journal of Transportation Engineering. Submitted December 17, 2010; accepted June 7, 2011;
           posted ahead of print June 10, 2011. doi:10.1061/(ASCE)TE.1943-5436.0000306


number of blows applied for compaction of specimen and average air voids were similar to the

mix of unwashed aggregates.

       The DBM mix with lime for washed granite aggregate was produced again but the

process of mixing lime with the aggregate was altered. In this case, the aggregate was washed

and dry hydrated lime was added on wet aggregate and mixed properly. The aggregate was




                    t
                  ip
dried in an oven at a temperature of 135oC to 145oC for 30 minutes. The addition of dry




             d cr
hydrated lime on wet aggregate surfaces was typically more effective than addition of dr y

lime during the preparation of mix. The AASHTO T 283 test was conducted and a sharp




           te s
         di nu
increase in TSR value was observed. The value increased from 78.3 to 83.7%. The number of

blows applied for compaction of specimen and average air voids were similar to the mix of
       ye a
unwashed aggregates. The same procedure was repeated for BC mixes. The results obtained are
     op M
given in Table 13.

Mean TSR and Chemical Analysis of Aggregates
   C ted


Figure 2 compares the mean TSR for samples with and without anti-stripping agent for DBM

and BC mixes. The results of the AASHTO T 283 mixes demonstrate that mean TSR value
 ot p



vary with chemical content present in the aggregates. Hardwar quartzite, which contains large
N ce




amount of potassium and little amount of calcium, shows least TSR value among all the mixes
  Ac




whereas limestone which has high content of calcium and negligible amount of potassium shows

maximum tensile strength. The study indicates that aggregates containing alkali metallic

elements like potassium exhibited relatively high moisture sensitivity for the bitumen used in

this study. On the other hand, there were very little indications of moisture sensitivity for

aggregates containing calcium, magnesium and iron.




                                                 17

                      Copyright 2011 by the American Society of Civil Engineers
     Journal of Transportation Engineering. Submitted December 17, 2010; accepted June 7, 2011;
           posted ahead of print June 10, 2011. doi:10.1061/(ASCE)TE.1943-5436.0000306


CONCLUSIONS

The following conclusions are drawn from the study:-

       A correlation between the OBC of DBM mix and BC mix was observed. In case the

specific gravity of aggregate is more than 2.7 then the OBC of DBM and BC mix of same

aggregate varies by an amount of 0.4% and if specific gravity of aggregate is less than 2.7 then




                    t
                  ip
the difference varies by an amount of 0.45 to 0.50% provided aggregate is of same source and




             d cr
having same mineral and chemical composition. In case of Hardwar aggregate, OBC values were

erratic since aggregate was river shingle which varies in its mineral and chemical composition.




           te s
         di nu
       The OBC difference of mixes prepared with lime and without lime generally lies between

0.10 and 0.15% provided aggregate is of same source and having same mineral and chemical
       ye a
composition.
     op M
       Results obtained in this study indicate that the tensile strength ratio of two DBM mixes

(Granite and Hardwar quartzite) did not satisfactorily meet the MoRTH criteria even on addition
   C ted


of 2% lime, these values were 78.3% and 78.6%, however aggregates had passed the physical

requirements test and ASTM D 1075-54 test.
 ot p



       The tensile strength ratio of granite aggregate gets improved from 70% to 83.7% by using
N ce




washed aggregate and by modifying the procedure of lime addition in the mix. The addition of
  Ac




dry hydrated lime on washed and wet aggregate surfaces was typically more effective than

addition of dry hydrated lime in dried and unwashed aggregates.

       The tensile strength ratio of BC mix satisfactorily met the MoRTH criteria on addition of

2% lime in the mix and the tensile strength ratio of granite aggregate improved from 72.8% to

86.3% on washing the aggregate and by modifying the procedure of lime addition in the mix.

       Evenly distributed and well-dispersed treatment of hydrated lime is necessary to



                                                 18

                      Copyright 2011 by the American Society of Civil Engineers
     Journal of Transportation Engineering. Submitted December 17, 2010; accepted June 7, 2011;
           posted ahead of print June 10, 2011. doi:10.1061/(ASCE)TE.1943-5436.0000306


maximize its beneficial effects on mixture performance.

       Mixes treated with hydrated lime performed better than untreated mixes due to the

following combined effects of hydrated lime i.e. due to increase in stiffness, strength, and

toughness of mix that induces better resistance of mix against degradation in the presence of

moisture and also due to the enhancement o f asphalt-aggregate interfacial bonding that produces




                    t
                  ip
better resistance to stripping.




             d cr
       It was observed during the vacuum saturation that Marshall Samples prepared with

limestone aggregate comparatively took 25 to 30 minutes more than other type of aggregates to




           te s
         di nu
achieve a saturation level of 55- 70%.

       The presence of calcium carbonate in aggregate can be verified in field conditions by
       ye a
treating the aggregate with acids used for domestic purposes to avoid addition of lime in the mix
     op M
and also to have economical use of bitumen.

       Mixtures from aggregates containing alkali metallic elements like potassium exhibited
   C ted


relatively high moisture sensitivity for the bitumen used in this study. Potassium gives the

surfaces that are more reactive with the more highly polar water. Therefore the Hardwar
 ot p



aggregate, having high potassium content exhibited less tensile strength ratio. On the other hand,
N ce




there were comparatively lesser indications of moisture sensitivity for aggregates containing
  Ac




calcium, magnesium and iron.

       Minimum 2 percent of hydrated lime as a filler in asphalt mixes would reduce the

moisture susceptibility of aggregates as specified in IRC: 111-2009, however chemical analysis

of aggregates should also be carried out or area specific mineralogical data should be procured

from the geological departments.




                                                 19

                      Copyright 2011 by the American Society of Civil Engineers
       Journal of Transportation Engineering. Submitted December 17, 2010; accepted June 7, 2011;
             posted ahead of print June 10, 2011. doi:10.1061/(ASCE)TE.1943-5436.0000306


NOTATIONS

BC               = Bituminous Concrete

CA               = Coarse Aggregate

DBM              = Dense Bituminous Macadam

HMA              = Hot Mix Asphalt




                    t
                  ip
MoRTH            = Ministry of Road Transport and Highways




             d cr
OBC              = Optimum Bitumen Content

VFB              = Voids filled with bitumen




           te s
         di nu
VMA              = Voids in Mineral Aggregate

REFERENCES
       ye a
Chen, J., Lin, K., and Young, S. (2004). “Effects of crack width and permeability on moisture-
     op M
induced damage of pavements.” J. Materials in Civil Eng., 16 (3), ASCE, 276 – 282.

Cheng, D., Little, D.N., Lytton, R.L., and Holtse, J.C.(2002). “Use of surface free energy
   C ted


properties of asphalt – aggregate system to predict damage potential.” J. association of asphalt

paving technologists, 78, 59 – 88.
 ot p
N ce




Curtis, C.W., Ensley, K. and Epps, J.(1993). “Fundamental properties of bitumen–aggregate

interactions including adhesion and absorption.” SHRP 341, NRC: Washington, DC.
  Ac




Hicks, G., Santucci, L., and Aschenbrener (2003). “Introduction and objectives of moisture

sensitivity of asphalt pavements.” National Seminar, TRB, San Diego, California. Washington.

Huang, S.C., Robertson, R.E., Branthaver, J.F., and Petersen, J.C. (2005). “Impact of lime

modification of asphalt and freeze – thaw cycling on the asphalt – aggregate interaction and

moisture resistance to moisture damage.” J Materials in Civil Engineering, 17 (6), ASCE,711 –

718.


                                                   20

                        Copyright 2011 by the American Society of Civil Engineers
     Journal of Transportation Engineering. Submitted December 17, 2010; accepted June 7, 2011;
           posted ahead of print June 10, 2011. doi:10.1061/(ASCE)TE.1943-5436.0000306


IRC : 111 (2009). “ Specifications for dense graded bituminous mixes”. Indian Road Congress,

New Delhi, pp 3-19.

Jones, A., Islam,M.S., Mortimer,M. and Palmer, D. (2004). “Alkali ion migration in albite and

K-feldspar”. Phys. Chem. Miner., 31, 313–320.

Little, D., and Jones, D. (2003). "Chemical and mechanical processes of moisture damage in hot-




                    t
                  ip
mix asphalt pavements." National Seminar on Moisture Sensitivity of Asphalt Pavements, TRB,




             d cr
San Diego.

Mertens, E.W. and Wright, J.R. (1959). “Cationic emulsions: How they differ from conventional




           te s
         di nu
emulsions in theory and practice”. Highway Res. Board Proc., 38, 386–397.

Mohamed, E.H., Halim, and Kennepoh, G.J. (1993). “Assessment of
       ye a                                                                       the   influence   of

compaction method on asphalt concrete resistance to moisture damage.” J. Construction
     op M
and Building Materials, 7 (3), 149 – 156.

Roberts, F.L., Kandhal, P.S. and Brown, E.R. (1991). “Hot mix asphalt materials, mixture
   C ted


design, and construction”, Library of Congress, NAPA publication: Lanham.

Shanmugasundram, V., and Thirunakkarasu, D. (2005). “An analysis of causes of premature
 ot p



failure of bituminous pavements in national highways of Tamilnadu state in India.” J. Indian
N ce




Highways, 33(9), 123-124.
  Ac




                                                 21

                      Copyright 2011 by the American Society of Civil Engineers
    Journal of Transportation Engineering. Submitted December 17, 2010; accepted June 7, 2011;
          posted ahead of print June 10, 2011. doi:10.1061/(ASCE)TE.1943-5436.0000306




FIGURE CAPTION LIST



Fig 1 Flow Chart for Laboratory Work Procedure


Fig 2 Variation in Mean TSR (%) with Chemical Composition of Aggregates




                    t
                  ip
             d cr
           te s
         di nu
       ye a
     op M
   C ted
 ot p
N ce
  Ac




                                                22

                     Copyright 2011 by the American Society of Civil Engineers
Journal of Transportation Engineering. Submitted December 17, 2010; accepted June 7, 2011;
      posted ahead of print June 10, 2011. doi:10.1061/(ASCE)TE.1943-5436.0000306


                              Table1 Types of Aggregates Used
Ser No        State                          Region                          Aggregate
  A       Uttar Pradesh               Jhansi- Bundelkhand                     Granite
   B       Uttrakhand                      Dehradun                          Limestone
   C       Rajasthan                        Jodhpur                          Sandstone
  D        Uttrakhand                       Hardwar                          Quartzite
   E       Delhi NCR                            -                            Quartzite




Accepted Manuscript
Not Copyedited


                                            23

                 Copyright 2011 by the American Society of Civil Engineers
Journal of Transportation Engineering. Submitted December 17, 2010; accepted June 7, 2011;
      posted ahead of print June 10, 2011. doi:10.1061/(ASCE)TE.1943-5436.0000306


                    Table 2 Aggregate Grading and Bitumen Content

       Specification                   DBM                               BC
         Grading                1                 2              1               2
        Nominal            37.5 mm           26.5mm           19mm            13.2mm
        maximum
      aggregate size
     Layer thickness      75-100mm          50-75mm           50mm            25/40mm
         IS Sieve          Cumulative percent by weight of total aggregate passing
        size(mm)
            45                100
           37.5             95-100             100
           26.5              63-93           90-100            100
            19                  -             71-95           90-100            100
            13               55-75            56-80           59-79           90-100
           9.5                  -                 -           52-72            70-88
           4.75              38-54            38-54           35-55            53-71
           2.36              28-42            28-42           28-44            42-58
           1.18                 -                 -           20-34            34-48
           0.6                  -                 -           15-27            26-38
           0.3                7-21             7-21           10-20            18-28
           0.15                 -                 -            5-13            12-20
          0.075               2-8              2-8              2-8            4-10
        Bitumen               4%              4.5%             5.2%            5.4%
        content**




Accepted Manuscript
Not Copyedited
                                             24

                  Copyright 2011 by the American Society of Civil Engineers
Journal of Transportation Engineering. Submitted December 17, 2010; accepted June 7, 2011;
      posted ahead of print June 10, 2011. doi:10.1061/(ASCE)TE.1943-5436.0000306


           Table 3 Requirements of the Dense Graded Bituminous Mix

           Properties              Viscosity grade paving bitumen            Test Method
       Compaction level                    75 blows on each
      (number of blows)                  face of the specimen
      Minimum stability                            9.0                  AASHTO T 245
         (KN at 60C)
      Marshall flow(mm)                           2-4                   AASHTO T 245
         % Air voids                              3-5                   MS-2 and ASTM
                                                                              D 2041
         %Voids filled                           65-75                        MS-2
      with bitumen(VFB)
    Tensile strength Ratio                  80% minimum                 AASHTO T283
     Coating of aggregate                   95% minimum                      IS: 6241
    Particles with bitumen
                             %Voids in mineral aggregate VMA
      Nominal Maximum              Min % VMA related to designed
     Particle size(mm)                      % air voids
                                   3                 4              5
              9.5                  14              15              16
              13.2                 13              14              15
              19.0                 12              13              14
              26.5                 11              12              13
              37.5                 10              11              12




Accepted Manuscript
Not Copyedited
                                            25

                 Copyright 2011 by the American Society of Civil Engineers
Journal of Transportation Engineering. Submitted December 17, 2010; accepted June 7, 2011;
      posted ahead of print June 10, 2011. doi:10.1061/(ASCE)TE.1943-5436.0000306


                      Table 4 Summary of Marshall Stability Tests
 Aggregate Specific       Type of    Anti            Volumetric Properties        OBC
           Gravity         Mix       Strip                                        (%)
                                                    Air      VMA        VFB
            (CA)                     Agent
                                                  Voids(%)    (%)       (%)
                          DBM         No            4.30     15.39      73.0      4.83
  Granite      2.64       DBM         Yes           3.30     14.90      82.0      4.98
                           BC         No            5.00     17.40      71.0      5.34
                           BC         Yes           3.90     16.44      76.5      5.45
                          DBM         No            3.80     15.26      76.0      4.58
 Limestone     2.88        BC         No            3.00     15.10      85.0      4.94
                          DBM         No            4.15     15.29      75.0      4.77
 Sandstone     2.73       DBM         Yes           3.40     15.08      77.3      4.82
                           BC         No            3.95     16.23      76.8      5.13
                           BC         Yes           3.70     15.73      79.6      5.22
                          DBM         No            4.30     15.18      72.0      4.77
 Hardwar       2.66       DBM         Yes           3.00     14.88      78.3      5.01
 Quartzite                 BC         No            3.70     16.56      75.2      5.32
                           BC         Yes           3.30     15.74      79.1      5.35
  Delhi                   DBM         No            4.30     14.76      72.3      4.35
 Quartzite     2.82       DBM         Yes           3.68     14.56      74.9      4.50




Accepted Manuscript
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                                             26

                 Copyright 2011 by the American Society of Civil Engineers
Journal of Transportation Engineering. Submitted December 17, 2010; accepted June 7, 2011;
      posted ahead of print June 10, 2011. doi:10.1061/(ASCE)TE.1943-5436.0000306


                Table 5 Chemical Analysis of Aggregates Using AAS

   Aggregate             Chemical contents of the aggregates studied (% by weight).
                        Calcium              Iron           Magnesium          Potassium
                          Ca                  Fe               Mg                  K
    Granite              11.20               4.46             6.40               2.60
   Limestone             30.41               6.63               12.2             1.00
   Sandstone              6.66              22.57               3.55             2.20
    Hardwar               1.82              15.54              23.90             10.60
   Quartzite
 Delhi Quartzite          9.20               3.60               5.50             2.20




Accepted Manuscript
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                                              27

                   Copyright 2011 by the American Society of Civil Engineers
Journal of Transportation Engineering. Submitted December 17, 2010; accepted June 7, 2011;
      posted ahead of print June 10, 2011. doi:10.1061/(ASCE)TE.1943-5436.0000306


       Table 6 Moisture Susceptibility Test Results on Loose Mixtures
           of Granite, Sandstone, Limestone and Delhi Quartzite

                                         Moisture Susceptibility
                    Aggregate                 Boiling Water
                                         as per ASTM D 3625-91
                  Granite                         < 5%

                  Sandstone                        < 5%
                  Limestone                        < 5%
                  Delhi                            < 5%
                  Quartzite
                  Hardwar                          >5%
                  Quartzite




Accepted Manuscript
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                                            28

                 Copyright 2011 by the American Society of Civil Engineers
 Journal of Transportation Engineering. Submitted December 17, 2010; accepted June 7, 2011;
       posted ahead of print June 10, 2011. doi:10.1061/(ASCE)TE.1943-5436.0000306




                      Table 7 Retained Stability as per ASTM D 1075-54
Aggregate           Retained       Retained       Retained       Retained
  type           Stability (DBM Stability (DBM  Stability (BC  Stability (BC
                 without lime)% without lime)% without lime)% without lime)%
 Granite            87.9           95.2           89.1           96.8
Limestone            98.8                 -                 98.0                 -
Sandstone             83                 94                 87.8                97
Hardwar              80.2               91.8                86.5               94.5
quartzite
 Delhi               84.5               93.9                  -                  -
Quartzite




Accepted Manuscript
Not Copyedited


                                              29

                  Copyright 2011 by the American Society of Civil Engineers
 Journal of Transportation Engineering. Submitted December 17, 2010; accepted June 7, 2011;
       posted ahead of print June 10, 2011. doi:10.1061/(ASCE)TE.1943-5436.0000306


    Table 8 Tensile Strength Ratio as per AASHTO T283 on Granite Aggregate
Type of Mix       State of          No of     Adjusted     Avg Air   Vacuum     TSR %
                  Samples          Samples     Blows       Voids % Saturation %
DBM without      Conditioned         03          25          7.1      63-68      70.0
   Lime         Unconditioned        03          25          6.9         -
DBM with         Conditioned         03          21          7.31     63-70      78.3
  Lime          Unconditioned        03          21          7.32        -
BC without       Conditioned         03          24          6.7      57-65      72.8
   Lime         Unconditioned        03          24          6.9         -
 BC with         Conditioned         03          21          7.4      65-70      82.35
  Lime          Unconditioned        03          21          7.2         -




Accepted Manuscript
Not Copyedited


                                             30

                  Copyright 2011 by the American Society of Civil Engineers
 Journal of Transportation Engineering. Submitted December 17, 2010; accepted June 7, 2011;
       posted ahead of print June 10, 2011. doi:10.1061/(ASCE)TE.1943-5436.0000306


       Table 9 Tensile Strength Ratio as per AASHTO T283 on Limestone Aggregate
Type of Mix State of Samples     No of Adjusted Avg Air     Vacuum     TSR %
                                Samples Blows Voids % Saturation %
  DBM           Conditioned       03         22    7.6       60-64      92.29
               Unconditioned      03         22    7.2         -
  BC            Conditioned       03         22    6.3       56-58      93.1
               Unconditioned      03         22    6.4         -




Accepted Manuscript
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                                             31

                  Copyright 2011 by the American Society of Civil Engineers
  Journal of Transportation Engineering. Submitted December 17, 2010; accepted June 7, 2011;
        posted ahead of print June 10, 2011. doi:10.1061/(ASCE)TE.1943-5436.0000306


       Table 10 Tensile Strength Ratio as per AASHTO T283on Sandstone Aggregate
  Type of Mix       State of       No of    Adjusted Avg Air  Vacuum     TSR
                    Samples       Samples     Blows Voids % Saturation % %
DBM without Lime  Conditioned        03        26      7.08    65-70     74.29
                     Unconditioned         03          26         6.8            -
  DBM with            Conditioned          03          23         6.33         64-70     84.0
    Lime             Unconditioned         03          23         6.25           -
   BC without         Conditioned          03          24         6.7          57-65     76.0
     Lime            Unconditioned         03          24         6.9            -
   BC with            Conditioned          03          19         7.32         63-72     87.0
    Lime             Unconditioned         03          19         7.14           -




Accepted Manuscript
Not Copyedited


                                                32

                   Copyright 2011 by the American Society of Civil Engineers
Journal of Transportation Engineering. Submitted December 17, 2010; accepted June 7, 2011;
      posted ahead of print June 10, 2011. doi:10.1061/(ASCE)TE.1943-5436.0000306


  Table 11 Tensile Strength Ratio as per AASHTO T283 on Hardwar Quartzite

Type of Mix        State of         No of Adjusted Avg Air Vacuum   TSR %
                   Samples         Samples Blows Voids Saturation %
                                                     %
DBM without      Conditioned         03      31      6.8    61-66    68.0
   Lime         Unconditioned        03      31      6.9      -
DBM with         Conditioned         03      28      6.7    57-67    78.6
  Lime          Unconditioned         03          28        6.4          -
BC without       Conditioned          03          27        7.0        60-66        71.6
   Lime         Unconditioned         03          27        6.7          -
BC with          Conditioned          03          23        7.1        62-68        81.3
 Lime           Unconditioned         03          23        7.3          -




Accepted Manuscript
Not Copyedited


                                            33

                 Copyright 2011 by the American Society of Civil Engineers
Journal of Transportation Engineering. Submitted December 17, 2010; accepted June 7, 2011;
      posted ahead of print June 10, 2011. doi:10.1061/(ASCE)TE.1943-5436.0000306


  Table 12 Tensile Strength Ratio as per AASHTO T283 on Delhi Quartzite

 Type of Mix          State of        No of Adjusted         Avg Vacuum       TSR %
                      Samples        Samples Blows            Air Saturation%
                                                            Voids %
 DBM without       Conditioned          03          24        6.9    61-63     72.2
    Lime          Unconditioned         03          24        7.2      -
  DBM with         Conditioned          03          22         7.0           59-65   83.5
    Lime          Unconditioned         03          22         7.3             -




Accepted Manuscript
Not Copyedited


                                             34

                 Copyright 2011 by the American Society of Civil Engineers
   Journal of Transportation Engineering. Submitted December 17, 2010; accepted June 7, 2011;
         posted ahead of print June 10, 2011. doi:10.1061/(ASCE)TE.1943-5436.0000306


Table 13 Tensile Strength Ratio as per AASHTO T283 on Washed Granite Aggregate
 Type of Mix         State of Samples No    ofAdjusted Avg       Vacuum       TSR%
                                      Samples Blows    Air Voids Saturation %
                                                       %
  DBM without Lime      Conditioned      03      25       7.2        63-69     72.9
  (washed aggregate) Unconditioned       03      25       7.1          -
   DBM with Lime         Conditioned         03         21        7.22          62-69   83.7
  (washed aggregate)
                        Unconditioned        03         21        7.30            -
   BC without Lime       Conditioned         03         24         6.9          59-68   74.3
  (washed aggregate)
                        Unconditioned        03         24        6.8             -
    BC with Lime         Conditioned         03         21        7.2           68-70   86.1
  (washed aggregate)    Unconditioned        03         21        7.2             -




Accepted Manuscript
Not Copyedited


                                               35

                    Copyright 2011 by the American Society of Civil Engineers
Fig 1 Flow Chart for Laboratory Work Procedure.pdf

                      Journal of Transportation Engineering. Submitted December 17, 2010; accepted June 7, 2011;
                            posted ahead of print June 10, 2011. doi:10.1061/(ASCE)TE.1943-5436.0000306




                  Selection of aggregates having different chemical and mineralogical composition. 



                              Sieve analysis of aggregate and proportioning of material 



                             Determination of specific gravity of bitumen and




                             Preparation of Marshall samples and testing to determine OBC 



                                 Ultimately conduct moisture susceptibility related tests 



                                   Fig 1 Flow Chart for Laboratory Work Procedure




              Accepted Manuscript
                   




              Not Copyedited


                                       Copyright 2011 by the American Society of Civil Engineers
Fig 2 Variation in Mean TSR.pdf

                    Journal of Transportation Engineering. Submitted December 17, 2010; accepted June 7, 2011;
                          posted ahead of print June 10, 2011. doi:10.1061/(ASCE)TE.1943-5436.0000306



                   100                                              TSR
                                                                                                      calcium            Iron
                     90                                                                               Magnesium          Potassium
                                                                                           TSR                                 TSR
                     80                    TSR                                                               TSR
                     70
                     60
                     50
                     40                          Ca
                     30                                                        Fe                          Mg
                     20                                                                               Fe
                            Ca                             Mg                                                   K   Ca
                     10          Fe Mg K              Fe                  Ca        Mg K         Ca                      Fe Mg K
                                                                K
                      0
                                 Granite           Limestone               Sandstone              Hardwar           Delhi Quartzite
                                                                                                  Quartzite

                          Fig 2 Variation in Mean TSR (%) with Chemical Composition of Aggregates




              Accepted Manuscript
              Not Copyedited


                                           Copyright 2011 by the American Society of Civil Engineers

				
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