NANOCLAY MODIFIED ASPHALT

Chandni J Basu Assistant Professor Department of Civil Engineering Mar Baselios College ofEngg. & Technology

SHAHIN M B56

S6 CE1Mar Baselios College of

Engg. & Technology

OVERVIEW• INTRODUCTION• MATERIALS USED FOR MODIFICATION• PREPARATION AND CHARACTERIZATION • ENGINEERING PROPERTIES• CONCLUSION

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INTRODUCTION

• Nanoclay are Eco friendly easily available sustainable

material which has excellent engineering properties.

• Asphalt modifications are limited to elastomeric and

plastomeric polymers, ground tire rubber.

• Current modified asphalts are not durable and results in

cracking. Hence modification is necessary.

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CLAY

• Clay is a naturally occurring material composed primarily of fine grained minerals.• It shows plasticity through a variable range of water content

and can be hardened when dried or fired• Under Phyllosilicates clays are commonly divided into • Kaolinite• Montmorillonite• Illite• Chlorite

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NANOCLAY?

• Nanoclay are Phyllosilicates which have a high aspect ratio and with at least one dimension of the particle in the nanometer range. • The purity and NANO exchange capacity of the nano-

clay are also critical characteristics. • Impurities results in poor impact and tensile

properties. • Ability to have large active surface area.• The cation exchange capacity(CEC) provides the surface

activity necessary for acceptance of modifiers.

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Montmorillonite

structure [1]

• Commonly used Nanoclay for asphalt modification• Cation exchange

capacity ranges from 80 to 120 meq /100 grams.• Have large active

surface area of 700 to 800 m2/gram.

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Preparation and characterization

• The surfactant modified Nanoclay is dispersed in organic solvent (isopropanol)• Silane coupling agent is added with continuous stirring in a

water bath until the solvent is completely evaporated.• The products are then dried in a vacuum at approximately

80°C and filtered using a 280 mesh.• The product is mixed with Asphalt in 160°C and mixed at

2500rpm for 3 hours using high-shear mixer.

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High Shear Mixer[1]

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Structure of Modified Asphalt[1]

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Morphological Characterization

• Tool used for identifying the atomic and molecular structure of a material.• Done by X-ray diffraction(XRD) technique.• XRD provides a quantitative analysis of the interlayer gallery

spacing and to determine the extent of dispersion of Nanoclay.• Inter plane spacing indirectly denotes the Miller Indices of

the Sample.

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Morphological Characterization(contd.)

XRD plot for Nanoclay[2]

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Morphological Characterization(contd.)

XRD plot for US 127 binder[2]

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Morphological Characterization(contd.)

XRD plot for US 127 Nanoclay modified asphalt binder[2]

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Toughness of the Modified Binder

• Toughness is really a measure of the energy a material can absorb before it breaks.• Area under the stress-strain curve for the direct

tensile is used to determine the toughness.• Test was conducted by Direct tensile tester at 18°C.• Nanoclay increase the toughness of the asphalt

binder relative to the original binder.• Due to stiffening behavior of Nanoclay as they

form bond chains within the binder.

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Toughness(contd.)

Toughness results for original binder & Nanoclay modified binders[3]

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Aging • When asphalt is aged, it hardens and becomes brittle and

thus an asphalt pavement will be damaged.• Aging can be due to defects on pavement or environmental

exposure and loading• Exfoliated structure of Nanoclay modified Asphalt improves the aging resistance.• By producing an effective barrier to oxygen, water ,organic solvents and UV rays.

Modified Asphalt Structure[4]16

Aging(contd.)

• Aging Index(AI) is used to determine the aging of the binder.• The AI of the binder is defined here as the ratio of the

complex shear modulus at 0.1 rad/s after and before the rolling thin film oven aging.

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Aging(contd.)

Comparison of the AI ratio shear modulus between the base and modified bitumen [5] 18

Moisture Susceptibility

• Moisture Susceptibility was found by Surface energy method using Compatibility Ratio(CR).• CR is defined as the work of adhesion of an aggregate and

binder system (dry condition) to the work of adhesion of the same system in presence of water (wet condition).• The higher the CR value, the higher the moisture resistance

of the aggregate-binder system.

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Moisture Susceptibility(contd.)

• Compatibility of aggregate and binder systems reduces when Nanoclay is blended with the neat binder, the moisture resistance reduces

Variations compatibility ratios for different aggregate-binder systems: (a) acidic aggregates, (b) basic aggregates[6]

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Resistance to Deicing agents & Cost Evaluation.

• Direct tensile strength is conducted on Nanoclay- Asphalt mix with NaCl, CaCl2 , MgCl2

• Nanoclay Modified asphalts acted inert to all deicing salts and retains high tensile strength.• Can be used to modify lower grade binder at very low cost.• By adding Nanoclay the cost of binder can be reduced by

22-33%.

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CONCLUSION

• Sustainable and Ecofriendly.

• Compatible and Stable with Asphalt.

• Improved the tensile strength of binder.

• Durable under heavy vehicle loads and Temperature

Variations.

• Resistance to Deicing agents.

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REFERENCES1. Saeed Ghaffarpour Jahromi, Behrooz Andalibizade, and

Shahram Vossough , Engineering properties of nanoclay modified asphalt concrete mixtures : The Arabian Journal for Science and Engineering, Volume 35, Number 1B

2. Zhanping You, Julian Mills-Beale, Justin M. Foley(2010).Nanoclay-modified asphalt materials: Preparation and characterization: Construction and Building materials .15 April 2010.

3. Mohammad Hossein Esfahani, Ali Asadollahi baboli : aboratory Investigation of the Fracture Properties of Nanoclay-Modified Asphalt Materials under Direct Tensile Test : International Journal on Mechanical Engineering and Robotics :Volume-1, Issue-1, 2013

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REFERENCES(contd.)4. Changqing Fang, Ruien Yu, Shaolong Liu1: anomaterials

Applied in Asphalt Modification: A Review : Journal material, Science Direct , 2013, 29(7), 589-594

5. Gang Liu, Shaopeng Wu, Martin van de Ven:Characterization of Organic Surfactant on Montmorillonite Nanoclay to Be Used in bitumen: Journal of materials in civil engineering , ASCE, AUGUST 2010

6. Zahid Hossain, Musharraf Zaman, Takumi Hawa: Evaluation of Moisture Susceptibility of Nanoclay-Modified Asphalt Binders through the Surface Science Approach, Journal of materials in civil engineering , ASCE, 27(10)

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THANK YOU

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