minnesota’s preventive maintenance study
TRANSCRIPT
National Pavement Management Conference Norfolk, Virginia
May 6-9, 2007
Minnesota’sPreventive Maintenance Study
The BIG Question…How effective are preventive maintenance
treatments at extending pavement life ?
Simple enough…
…Or is it ?
Pathway Services© Digital Inspection Vehicle
RQI = Roughness Index
SR = Cracking Index
))(( SRRQIPQI =
Mn/DOTPavement
Indices• RQI• SR• PQI
Overall Index
Indices
Pavement Defects
Transverse Cr. (L,M,H)Longitudinal Cr. (L,M,H)Longitudinal Joint (L,M,H)Multiple Cr.Alligator Cr.RuttingRaveling/WeatheringPatching
Spalled Joints (L & H)FaultingCracked PanelsBroken Panels100% Overlaid PanelsPatches over 5 sq.ft.D-Cracked Panels
Bituminous Defects Concrete Defects
Highway Pavement Management Application (HPMA)
HPMA Start Screen
Performance Analysis TopicsForecasting Future Performance
Performance ComparisonsBy RehabilitationPreventive Maintenance Strategies
Modes of DeteriorationRideDominate Distresses
Forecasting: Analysis Steps Used
Query Data to Sub-categories by:Pavement TypeLast Rehab TypePreventive maintenance received
Fit TrendsIndex TrendsDistress Growth Trends
Compare Trends 0
20
40
60
80
100
0 5 10 15 20Ave
rage
Tra
ns. C
rack
Rat
ing
0%
20%
40%
60%
80%
100%
0.0
1.0
2.0
3.0
4.0
0 10 20
Age, Yrs.
Avg
. Rat
ing
RQISR
Does Maintenance Extend Life?
Dataset: All Bituminous over Aggregate Base in the Minnesota Trunk Highway System
Sub-CategoriesSections without any maintenanceSections with maintenance
Ride TrendsInitial Conclusion:
Sections with preventive maintenance have higher RQI and last longer.
2.02.22.42.62.83.03.23.43.63.84.0
0 5 10 15 20
Age since Construction, Yrs.
Ave
rage
Rid
e Q
ualit
y In
dex
WITH Prev. Maint.
W/O Prev. Maint.
Linear (WITH Prev.Maint.)Linear (W/O Prev.Maint.)
Surface Rating Trends
Initial Conclusion:
Sections with preventive maintenance have higher SR and take a couple years longer to deteriorate. 2.0
2.22.42.62.83.03.23.43.63.84.0
0 5 10 15 20
Age since Construction, Yrs.
Ave
rage
Sur
face
Rat
ing WITH Prev. Maint.
W/O Prev. Maint.
Poly. (WITH Prev.Maint.)Poly. (W/O Prev.Maint.)
Life extension
Pre-Existing Conditions
Are sections selected for preventive maintenance typical of all sections?
Do pre-existing conditions, if different, effect future performance?
Is Pavement Performance influenced by Agency Practice?
Selection Bias for Seal Coats: SR
3.50
3.55
3.60
3.65
3.70
3.75
3.80
3.85
3.90
3.95
4.00
0 5 10
Age Since Orig. Const., Yrs
Ave
rage
Sur
face
Rat
ing Before Seal Coat
Sections NotSealed
Selection Bias for Seal Coats: RQI
3.00
3.10
3.20
3.30
3.40
3.50
3.60
3.70
3.80
3.90
4.00
0 5 10
Age Since Orig. Const., Yrs
Ave
rage
Rid
e Q
ualit
y In
dex
Before Seal Coat
Sections NotSealed
RQI Carryover Effect?
y = -0.0418x + 3.5714R2 = 0.6993
y = -0.0784x + 3.5076R2 = 0.7757
2.0
2.5
3.0
3.5
4.0
-10 -5 0 5 10 15
Age from year of Seal Coat, Yrs.
BA
B: A
vera
ge R
QI
Before SCAfter SCNo Maint. SectionsLinear (Before SC)Linear (After SC)
SR Carryover Effect?
y = -0.011x + 3.8319R2 = 0.1565
y = -0.0555x + 3.8034R2 = 0.4182
2.0
2.5
3.0
3.5
4.0
-10 -5 0 5 10 15
Age from year of Seal Coat, Yrs.
BA
B: A
vera
ge S
R Before SCAfter SCNo Maint. SectionsLinear (Before SC)Linear (After SC)
Seal Coat: Selection Effect
• Conclude:– Pavements that are selected for seal coating are
in slightly better condition
– Pre-existing condition might serve to make seal coated sections appear to last longer
• How can we find out?– Control Sections
Control (“Do Nothing”) Section• Incorporate into PM Rating Process• Pair with similar Treated Section• Monitor Annually• Need more than Several per Treatment
Mode of DeteriorationWhich Distresses Rule?
• Transverse Cr. (L,M,H)• Longitudinal Cr (L,M,H)• Longitudinal Joint Deterioration (L,M,H)• Multiple Cr.• Alligator Cr.• Rutting• Raveling/Weathering• Patching
Mode of Deterioration1st Generation Flexible Pavements
Trans28%
Long9%
Joint36%
Mult13%
Allig0%
Rut14%
Rav0%
Pat0%
Mode of Deterioration(BOB Sections – Thin Overlay)
Trans33%
Long7%Long Jt
19%
Mult39%
Rav0%
Rut2%Allig
0%
Pat0%
Ride:Our Most Critical Distress on Bituminous
2.0
2.5
3.0
3.5
4.0
0 10 20
Age, Yrs.
Avg
. Rat
ing
RQISR
Summary• Bias Topics
• Situations that can Bias Trends- Performance reflects practice- Influence of previous condition history- Critical Modes of Deterioration
• Deterioration Modes• Deterioration of pavement along linear distresses• Ride
