Post on 16-Aug-2018
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