This presentation discusses pavement construction issues, and the use of interlayers in pavement widening. Prepared by Katie Strain and Michael Samueloff of TENCATE. Please remember to cite this research if the information you find here is used.
Narrow Pavement Widening - Enhancing Performance with Interlayers
1. All Data & analysis courtesy of John Bryce of Harris & Associates
WELCOME
Katie Strain
TenCate Mirafi â Roadway Reinforcement
Enhancing the Performance and Design Life of Roadways
Michael Samueloff
TenCate Mirafi - Pavement Solutions
Narrow Pavement Widening Using Interlayers
19. 19 | Road Show
MirafiÂź RS580i, RS380i & RS280i
Integration of 5 Key Properties for Base Reinforcement
and Subgrade Stabilization
- High Modulus especially in CMD
- High Water Flow/Permittivity
- Separation (US sieve #40)
- High Interaction Coefficient (Confinement)
- Product Identification
21. All Data & analysis courtesy of John Bryce of Harris & Associates
ï¶ Deterioration Causes & Delay
ï¶ Interlayer Types & Functionality
ï¶ Cost/Benefit
Geosynthetic Pavement Interlayers
22. All Data & analysis courtesy of John Bryce of Harris & Associates
Distressed Pavements
Pavement Deterioration
23. Subbase/Native
Crack Growth 1â / Yr Avg
HMA Layer
HMA Overlay
Thermal movement
Traffic Loading
Base
Moisture intrusion
Pavement Deterioration
From day ONE these forces are at work
Weather / Environmental Action
Deficiencies in design, construction and maintenance
Aging
24. Forces Interlayers Address
Pavement Deterioration
Water intrusion
Reflective Crack Forces
Base
Traffic Loading
Thermal Movement
PAVEMENT
SECTION
25. Protect base from moisture saturation
Pavement Interlayer Functionality
Point Load Distribution
Interlayer Functions that Delay Deterioration
Mitigate Impact of
Top
HMA
Layers
Base
Stress Absorbing/Dispersing Paving Interlayer
Bottom
HMA
Layers
Mitigates Weather /
Environmental Effects
Stops water intrusion
Thermal
MovementReturn and Severity
Delay
Crack
26. âOne major factor that degrades a roadbedâs ability
to function is the infiltration of water into the base
material.â
Caltrans Pavement Evaluation Manual
Pavement Condition Survey
John Poppe
FHWA - Moisture intrudes through pavement:
Asphalt up to 50%
Concrete up to 67%
Deteriorating Impact of Moisture Intrusion
27.
28. Drainage Quality Time Drainage Coefficient
Excellent 2 hours 1.2
Good 1 day 1.0
Fair 1 week 0.8
Poor 1 month 0.6
Very Poor Doesnât drain 0.4
Deteriorating Impact of Moisture in Base
29. Pavement Interlayer Value
HOW?
...Extend Life:
ïŒ Preserve base structural value
ïŒ Delay crack return & severity
ïŒ Add flexural strength to HMA
âŠGreater Value:
ïŒ Reduce impact of asphalt cost
i.e In Dec. 07, $175/ton, todayâŠ$650+
ïŒ Greater benefit at less cost
30. Pavement Interlayer Evolution
NEW?...Interlayer evolution to
higher levels of performance
ïŒto multifunctional, Moisture
barrier Plus reinforcement
ïŒto multi-axial reinforcement
ïŒto focus on in-place functionality
31. How Interlayers Work
STRAIN
ABSORBING
STRESS DISSIPATING
Mass to soak up
(Sponge)
Tensile strength and efficiency to disperse low strain
crack energy (Rebar) Multi-Axial strong all directions
Tighter bond,
thicker/more mass =
greater ability to
absorb = better
reflective crack
retardation
Tighter bond, higher, more efficient tensile strength, more
homogeneous the structure = greater ability to dissipate crack
energy = better reflective crack retardation
FABRICS
MAT
Multi-Axial
GRIDS
Continuous Strand Fiberglass
Bi-Axial I Multi-Axial
Interlayers Types
Pavement Interlayer Functionality
32. RECYCLABLE
With Asphalt forms Moisture Barrier
Description
With Asphalt absorbs and/or disperses crack forces
Multi-Axial, multi-directional reinforcing
Bi-Axial, 2 way reinforcing, weak at bias angle
With Asphalt tack forms a strong bond between layers
Mills completely and can be added back into new mix
Function
Pavement Interlayer Functionality
33. Bi-Axial Multi-Axial
Crack Stress Relief and Delay
Monolithic
bond
Mills + Recycles
into new mix
Wide Vs
Narrow
Rolls
Uncoated,
Flexible
Rolls
TenCate
Products
Interlayer Functionality Summary
Stress
Absorbing
Tensile to Reinforce
Stress Absorbing Geosynthetic Interlayer
Polypropylene Fabric
FUNCTIONALITY
Constructibility
Ease of
Installation
Description
Moisture
Barrier
Membrane
MPV
Fabric
YES YES NO NO YES Can Be YES YESPolypropylene Fabric
Fiberglass Tensile Reinforcing Geosynthetic Interlayers
Tru
Pave
Mat
Multi-Axial Mat YES YES YES Up to 80N YES YES YES YES
PGM
G4
Multi-Axial
Composite
YES YES YES Up to 100kN YES YES YES YES
PGM
G2
Composite YES YES Up to 100kN NO YES Can Be YES YES
FGÂč
PreCoated Self
Stick/Scrim
NO NO Up to 100kN NO NO YES NO NO
FGCÂČ
PreCoated
Composite
YES YES Up to 100kN NO YES Can Be NO NO
ÂčReplaced by G4, ÂČReplaced by G2
Fiberglass Tensile Reinforcing Geosynthetic Interlayers
Multi-Axial
Grids
Bi-Axial
35. Original Pavement
Hot AC Tack Coat
(Approx .25 Gal/SY)
Provides Moisture Barrier
Interlayer Installation
Bitumen Saturation and Fabric
âą Delays Reflective Cracking
âą Reinforces Overlay
âą Waterproofing membrane
NEW EXTENDED LIFE
ASPHALT SURFACE
Pavement Interlayer Installation
36. The Asphalt Pavement Analyzer - Wheel Track
Figure 5: Asphalt Pavement Analyzer â Wheel Track
Interlayer Functionality Study
37. Grid
IEF # of cycles with interlayer/#of cycles
to 100% crack on the control
Cycles to 100% failure
Interlayer Effectiveness and Total Life Averages
Interlayer Functionality Capability
MatFabricControl
38. Pavement Age (Time In Years)
Excellent
Good
Fair
Poor
Failed
Pavement
PavementCondition
Time For New Overlay
Possibly Recycle
Original Pavement HMA Overlay w/
Interlayers
HMA Overlay Only
Yr X Yr Y
Selection by Type/Functional Impact
No Interlayer
REHAB â OVERLAY PAVEMENT
Delay Deterioration - Extend Life (Yr Y â Yr X):
Mat 2.75 times
longer
Interlayer Impact on Pavement Deterioration Curve
Crack Delay
using an
interlayer
41. Interlayer Performance Compromised
1. Incomplete Interlayer System:
Includes Interlayer WITH asphalt
2. Installation quality
a. Asphalt tack
b. Overlay too thin
c. Lack of base prep
d. Uncut wrinkles
3. Site selected exceeds functionality
a. Unstable base
b. Unstable underlying surface
c. Wide cracks with excessive thermal movement
Expectation Not Met
42. Extreme Pavement and Base Failures
Base Failures
Extreme fatigue cracking/unstable base
Slab Fracture/Uneven
Extreme Fatigue Cracking
Caution! Not all conditions interlayer appropriate!
Performance Compromised: Site Selection
Mix Rutting
49. Interlayer Use Summary
ï¶Extend pavement life
ï¶Maximize base performance
ï¶Delay crack return & severity
ï¶Reduce impact of asphalt cost
ï¶Reduce maintenance & road closure
CHEAPEST INSURANCE TO:
50. MirafiÂź MTK Crack Solution
âą Seals crack âKeeps water out
âą Flexes to keep cracks sealed
âą Delays reflective cracking
âą Slows pavement deterioration
âą Fast, easy to install
âą Adheres to cleaned surface
âą Used in wide temperature range
âą Reduces traffic disruption
.
MirafiÂź MTK Roll Dimensions
.30 m x 15.2 m (12 in x 50 ft)
.46 m x 15.2 m (18 in x 50 ft)
.60 m x 15.2 m (24 in x 50 ft)
.91 m x 15.2 m (36 in x 50 ft)
Southwest WashingtonOne of first installations of our RS280i product just introduced. Same characteristics as 380i & 580i, just not as strong so it costs less
See where the geosynthetic is and then where the mud is pushing up where itâs not
Gals/min/ft2of material
Technology came from the pool covers we manufacture. Allows water thru but not sunlight.Double-weave
RS580i vs 600x
Coefficient of interaction1.0 â rock on rock0.0 â glass on glass
Legion Trail Park just outside of St. Louis, MO â geogrid was originally specified by the geotechContractor wanted to use SHOT rock â geosynthetic spec was changed to RS580i
High strength at low strain â we donât want it to stretch hardly at allFor comparison BX1200 - 600 lb/ft.
Results of an independent lab testing down in AtlantaRS580i outperforms all of our best productsProof is in the pudding
Now weâve covered the key functions of geosynthetics performing in a roadway
The Asphalt Pavement Analyzer is an established wheel tracking device that is configured to run both the Georgia Loaded Wheel and Wheel Track test methods. The primary difference in these methods is how the load is applied to the sample. The Georgia Loaded Wheel applies a load to a rubber hose that is resting on the sample. The Wheel Track applies the load using a steel wheel and is shown in Figure 5. The Wheel Trackapproach was selected for the APA-RCR.Several refinements were made to this method to produce a microstrain in the range of 600 to 800 and initiate crack propagation in less than 10,000 cycles (>3.5 hours). The stress was increased from 100 psi to 120 psi and beam dimensions were reduce to 3 inches in width by 2.5 inches in depth.
The orange bar graph is simple cycles to failure.The blue bar graph is showing that if a pavement with no interlayer cracks through at 1.0 then withMPV500 it will take 1.6 times longer for crack returnTruPave will take 2.75 times longerGrid will take 5.5 times longerIn other words, Theoretically, In these ideal lab conditions, if the un-reinforced asphalt pavement cracked at 1" per year then a 2" un-reinforced pavement will have cracks back in 2 yearsIn that same ideal lab situation if you use the following interlayer, cracks will be delayed for:MPV500 at 1.6 times or not back for 3.2 years or a 60% improvementTruPave at 2.75 times or cracks not back for 5.5 Years or a 175% improvementGrids at 5.5 Times or cracks not back for 11 Years or a 450% improvementTake away is only to clearly demonstrate the difference in performance capability with these three interlayer types.These test results are done in a controlled environment and isolate differences that help quantify the differential performance in this particular test of these three interlayers compared to a control.Which means we can say that if everything else is equal, this is a good measure of the differential in performance between these products that can be used to justify the value differential between each of them.Now of course, in the real world we do not have ideal nor controlled conditions--we have many variables! If we can determine the exact distress condition and know it was exactly like the last project with exact same traffic loads, exact same weather and environmental conditions with the exact same base conditions we could all be very confident in predicting the results possible in the real world--Of course this is not likely and makes our job much more difficult--but not impossible!When we relate this back to our specific experience with our past installs I think we all agree, we have had some significant improvement in performance that agencies have been very happy with and which indicate that in some applications the interlayer performed even better than the above test results would indicate.Eg. Santa Cruz where TruPave was installed over PCC with an overlay and at 8 Years still has no cracks. If in the un-reinforced 2" overlay, the cracks returned in 2 years then TruPave provided a 4 times or a 400% improvement already and still not cracks???