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Development of Emergency Pothole Repair Material Using Polyurethane for Asphalt Pavement
Presenter : Yeongmin Kim, Senior Researcher
Research Background
Traffic Increase Heavy Rain Material Change
Development of Pothole Resistance
Material and Repair Technology
MaintenanceMaterials Construction
Long-life PavementReduction in Traffic Accident, Maintenance Cost, Premature Failure
Pothole IncreaseTraffic
AccidentPavement
Failure
Causes of Pothole Occurrence
1. Existence of cavity in pavement
2. Poor drainage (pore water pressure)
3. Aggregate coated by excessive dust
4. Fragile aggregate
5. Overlay on weaken concrete pavement
Occurrence Causes
1. Drainage problem
2. Cracking
3. Poor construction of longitudinal joint
4. Bonding deficiency
5. Bad tack coat
1. Water, temperature(freeze and thaw), bad tack coat
2. Water, saturation degree, traffic
3. Dust and clay content
4. Aggregate durability
5. Water, water pressure
Influencing Factors
1. Water, saturation degree, water pressure,
air voids
2. Water, saturation degree, air voids
3. Air voids, density
4. Water, density
Literature
Review
Field
Survey
Pothole Cause #2
Poor Drainage
• Pothole occurs with the excessive water in pavement due to poor drainage
Pothole Cause #4
Poor Construction of Longitudinal Joint
• Insufficient compaction on the longitudinal joint between existing and new lanes
Pothole Cause #5
Bonding Deficiency
• A loss of bonding between repair material and existing pavement
- 25
- 20
- 15
- 10
- 5
0
0 5000 10000 15000 20000
Number of Wheel Passes
Imp
ressio
n,
mm
권
Post Compaction
Consolidation
Inverse Stripping
Slope
Inverse Creep
Slope
Stripping Point
Test Method for Pothole Evaluation 1
Hamburg Wheel-Tracking Test Result MVT (Material Verification Tester)
Test Method for Pothole Evaluation 2
Analysis Method of MVT Result
0
0.5
1
1.5
2
2.5
3
0 1000 2000 3000 4000 5000 6000 7000 8000
Inflection Point
Rutting
Slope
Stripping
Slope
Test Condition
• Water Bath Temp : 50℃• Hose Pressure : 100psi
• Axial Force : 100lb
Analysis Method
• Fixed Cycle(8000 cycles)
• Total Deformation(TD)
• Stripping Deformation(SD)
• SD/TD ratio
Test Results for Pothole Evaluation 1
Air Voids 2%
0
1
2
3
4
5
6
7
0 2000 4000 6000 8000
왕복 횟수( No )
De
form
ati
on
(mm
)
1cycle
2cycle
3cycle
0
1
2
3
4
5
6
7
0 2000 4000 6000 8000
왕복 횟수( No )
De
form
ati
on
(mm
)
1cycle
2cycle
3cycle
Air Voids 8%
0
1
2
3
4
5
6
7
0 2000 4000 6000 8000
왕복 횟수( No )
De
form
ati
on
(mm
)
1cycle
2cycle
3cycle
Air Voids 4%
Test Results for Pothole Evaluation 2
Air Void Frozen-Thaw TD(mm) SD(mm) SD/TD(%)
2%
1 cycle 0.273 - -
2 cycle 2.008 0.580 28.9
3 cycle 2.622 0.877 33.4
4%
1 cycle 1.953 0.682 34.9
2 cycle 3.013 1.027 34.1
3 cycle 5.400 1.898 35.1
8%
1 cycle 4.508 2.501 55.4
2 cycle 5.590 3.046 54.5
3 cycle 6.658 3.981 59.8
• TD : Total Deformation(Rutting + Stripping)
• SD : Stripping Deformation
Summary of Laboratory Test Results
• TD, SD, and SD/TD increase when the air voids are higher resulting in
more water absorption.
• Water in air voids causes large deformation by reducing binder adhesion
and bonding between binder and aggregate.
• As a number of cycle of frozen-thaw increases, TD value increases but
SD and SD/TD values are not changed significantly.
• Stripping Deformation value is not affected by a number of cycle of
frozen-thaw.
• The primary factor of pothole occurrence is the air voids.
Higher air voids increases the possibility of pothole occurrence.
A number of cycle of frozen-thaw is not main factor for stripping deformation.
Development of Waterscape Emergency Repair Material
Problems of existing repair materials
1. Poor workability
2. Poor adhesion with existing pavement
3. Long curing time
4. Bad compaction due to strong elastic restoring force
Need to improve the water resistance
Need to consider workability and short curing time
Polyurethane binder is selected, instead of cutback asphalt
binder which is normally used for emergency repair material.
Component of Waterscape Emergency Repair Material
Polyurethane (PU)
A polymer containing a large quantity of urethane links
Urea Reaction 2 R-N=C=O + H-O-H R-NHCONH-R + CO2
MDI Water Urea Gas
1. Waterscape material (excellent water resistance)
2. Shorter curing time and adjustable curing time by
catalyst (possible in production stage)
3. Outstanding adhesion and chemical resistance
4. Oil is added to improve the workability
Flowchart of Development
Flowchart 1 Flowchart 2
Determined
gradation
0
10
20
30
40
50
60
70
80
90
100
0 0.075 0.15 0.33 1.18 2.36 4.75 9.5
Pe
rcen
t p
as
sin
g in
we
igh
t(%
)
s ieve size(mm)
CASE1 CASE2
0
100
200
300
400
500
600
700
800
부착
강도
(kg
f)
A B C CASE1 CASE2
보수재 종류
Evaluation of Material Properties
0.000
0.500
1.000
1.500
2.000
2.500
3.000
3.500
1일 2일 4일 8일 16일 32일
양생 시간(day)
인장
강도
(㎏/㎠
)
A
BC
CASE1CASE2
CASE1m(수침 후)CASE2m(수침 후)
CAS
E 1
CAS
E 2
1. Securing the stability to water, strong adhesion force, and increased strength
2. Development of cold-mix repairing asphalt for color asphalt pavement
3. Applicability to the area with residual water, and reduction of premature failure after repairing
Tensile StrengthMaterial Properties
Bond Strength
Bo
nd
ing s
tren
gth
(kgf)
Ten
sile
str
ength
(kgf/
cm2)
Curing time(day)
1day 2day 4day 8day 16day 32day
Type of repairing material