Material Control Knob

Fan Control Knob

Asphalt Concrete Specimen

Air Inlet

Paint Cup

Pressure Gage

15 cm

• Capturing and measuring the water contact angles

• Calculating the coefficient of friction

• Significant factors affecting superhydrophobicity

• Significant factors affecting skid resistance

100110120130140150160170180

3 6 9 12

Con

tact

ang

le (d

egre

es)

Spray time (seconds)

10% 20% 30% 40%

4 µL Water Droplet

Sony Camera

Spacer Block

Coated Asphalt Concrete Specimen

Probe

SpacerBlock

Sample Stage (Lateral Force)

Strain Gages (Normal) (Lateral)

Vertical Stage

Micrometer

(Side View)

Two-Sided Tape

Probe Arm

Asphalt Concrete Specimen

Friction Measurement

Paths

(Top View)

• Gradation

• Spray depositing the epoxy and PTFE

• Specimens

• Contact angle measurement

• The superhydrophobic coatings can be utilized in:• Ice formation and snow accumulation on pavedareas of airfields and roadways can cause seriousproblems leading to economical loss, andendangering passenger safety

• Paved areas with water repellent surfacesmimicking lotus leaves found in nature canminimize ice formation or snow accumulation

www.vosizneias.com Courtesy: CNN

Department of Civil, Construction & Environmental Engineering

Superhydrophobic Coatings on Asphalt Concrete Surfaces: Towards Smart Solutions for Winter Pavement Maintenance

Background

Major Professors: Dr. Halil Ceylan and Dr. Kasthurirangan Gopalakrishnan

Applications Results

Author: Ali ArabzadehCo-Authors: Halil Ceylan, Sunghwan Kim, and Kasthurirangan Gopalakrishnan

Research OutcomeThe PTFE spray time and dosage were significant factorsaffecting both the superhydrophobicity and skid resistance ofnano-coted asphalt concrete; the spray time of six secondsresulted in obtaining skid resistant surfaces.

Acknowledgements: The authors gratefully acknowledge the Federal Aviation Administration (FAA) for supporting this study.

www.flickr.com www.roadandtrack.com

Young Wenzel Cassie-Baxter𝜭𝜭 ˃ 90 𝜭𝜭 ˂ 90

• Contact angle concept

Hydrophobic Hydrophilic

• Types of Models explaining the hydrophobicity

Coated heated runway

• Coated paved areas must be skid resistant

www.lapsset.go.ke www.powerlanecorporation.com

Research Approach

0

20

40

60

80

100

0 0.5 1 1.5 2 2.5 3 3.5 4

Pass

ing

(%)

Sieve size ^ 0.45 (mm)

Restricted zone Maximum density lineControl points Blend

2-way ANOVAFactors P-value

Dosage (%) 0.001Spray time (s) 0.0001

0.19 0.

20

0.16

0.16

0.19

0.26

0.19

0.23

0.15

0.23

0.23

0.27

0.17

0.26

0.24

0.24

0.21

0.21

0.21

0.21

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

3 6 9 12

Coe

ffici

ent o

f fric

tion

Spray time (seconds)

10% 20% 30% 40% Control

y = 0.2532x - 4.0642R² = 0.9955

0123456789

15 25 35 45 55

Fric

tion

forc

e (m

N)

Normal force (mN)

• After performing a statistical design, the samples coated withPTFE were prepared, and tests were performed:

• Measurement of coefficient of friction

2-way ANOVAFactors P-value

Dosage (%) 0.016Spray time (s) 0.0002

α = 154° α = 161° α = 160°

Three measured water contact angles

µ𝑘𝑘= 0.25

Coated Vs Uncoated asphalt concrete

Close up view

The paths over which measurements were performed