High Friction Surface Treatments
High Friction Surface Treatment WSDOT’s Experience
Jeff Uhlmeyer WSDOT State Pavement Engineer
Rocky Mountain West Pavement Preservation Partnership Seattle, WA October 23-25, 2017
High Friction Surface Treatment - Background • HFS has gained popularity over the last decade in the United States for its crash reduction potential in locations which demand friction – Horizontal curves, locations with heavy braking such as approaches to intersections or crosswalks and/or steep grades
• Nine of the 39 states that have installed HFST have moved to aggressively deploy its use • Many states have documented high reductions in crashes at horizontal curves.
1. FHWA
2
High Friction Surface Treatment
• Durable, polish-resistant aggregate applied to an existing surface – Most common applications consist of calcined bauxite with a two-part epoxy resin
• Friction numbers are typically >70 – Average friction numbers on new HMA are generally in the 40 to 50 range
• Generally high benefit-cost ratio – Accidents drastically reduced
3
Mechanical Placement
4
Mechanical Placement
Mechanical/Manual Placement
5
Hand Placement
6
Hand Placement
7
WSDOT Projects •
2010 - SR 14 (WB On-Ramp at 164th Ave) Experimental Feature project – Two-lift mechanical installation – Third lift was placed in 2011
•
2014 - Bald Hills Rd. – Thurston County project – Manual installation using maintenance personnel
•
2015 - I-90 (WB On-Ramp at 148th St) and SR 526 (EB to I-5 SB On Ramp) placed under one contract
•
2016 - I-5 (SB On-Ramp to I-405), I-405 (WB On-Ramp to I-90), SR 14 (SB Off-Ramp to I-205), I-205 (3 Off-Ramps to SR 14) and SR 2 (Mainline) placed under three contracts
•
13 additional projects scheduled in the next three years.
8
SR 14 – 2013 (three years later)
9
SR 14 – 2016 (six years later)
10
Bald Hills Rd. – 2015 (one year later)
11
Bald Hills Rd. – 2016 (two yeas later)
12
Bald Hills Rd. – 2016 (two years later)
13
SR 526 to I-5 Ramp SB – 2016 (9 months later)
14
SR 526 to I-5 Ramp SB – 2016 (9 months later)
15
148th Street on ramp to I-90 WB – 2016 (9 months later)
16
148th Street on ramp to I-90 WB – 2016 (9 months later)
17
Issues Affecting HFST Performance • Raveling in roadway surface prior to installation • Existing longitudinal joint reflecting through • Existing cracks deteriorate after placement of HFST • Low density areas in HMA or distresses causing pop outs • Surface tension difference between HMA and resin compound • Are there alternate materials rather than Bauxite that would be effective (NCAT Study)
Therefore WSDOT developed criteria for HFST . . .
18
Criteria for HFST Projects
Pavements that are nearing their due year for rehabilitation should not receive HFST • HFST should only be placed on a pavement that is in relatively good condition (5 years or less in age but dependent on condition) – – – –
No structural-related cracking or rutting. No age-related alligator or longitudinal cracking Transverse cracking is okay provided the edges of the cracks are not raveled No cracks greater than ¼ inch in width
19
Criteria for HFST Projects (cont.)
– HFST should not be placed over longitudinal joints in the wheel path – The maximum rut depth should be less than 1/4 inch and at least 75% of the site should be less than 1/8 inch – No raveling, flushing or evidence of stripping – No drainage problems that result in water on the pavement surface during dry periods – Must have sufficient surface texture for a good bond
20
Friction Performance Bellevue / Eastgate – SB 148th to WB I90 Date tested Baseline FN before treatment Initial FN – after HFST 6-month performance 1 year FN performance 2 year FN performance
5/13/2015 7/7/2015 1/14/2016 8/16/2016 8/23/2017
Single lane ramp / ADT 11400 38.1 74.5 72.1 3.2% decline 71.4 1% decline 71.6 0.3% increase
Everett – EB 526 to SB I5 Baseline FN before treatment Initial FN – after HFST 6-month performance 1 year FN performance 2 year FN performance
Date, time and initials of last edit
Date tested 5/13/2015 7/7/2015 1/14/2016 8/16/2016 8/23/2017
Left lane (GP) / ADT 12650 38.7 82.9 76.6 7.6% decline 73.8 3.5% decline 67.6 8.4% decline
Right lane (HOV) / ADT 2400 39.7 86.0 77.5 77.8 71.9
10% decline 0.4% increase 7.6% decline
21
Friction Performance Factoria – SB 405 to WB I90 Baseline FN before treatment Initial FN – acceptance 8-month FN performance 1 year performance
Date tested 5/13/2015 8/16/2016 3/16/2017 8/23/2017
Left lane (GP) / ADT 20150 37.1 83.9 72.8 13% decline 69.8 4.1 decline
Right lane (HOV) / ADT 3090 43.0 87.1 79.3 9% decline 72.4 9.5% decline
Date tested 5/13/2015 8/16/2016 3/16/2017 8/23/2017
Left lane (GP) / ADT 18500 39.3 81.9 62.3 24% decline 63.4 1.7% increase
Right lane (GP) / ADT 7930 41.5 83.1 76.1 8% decline 71.6 6.3% decline
Lynnwood / Swamp Creek -SB I5 to SB 405 Baseline FN before treatment Initial FN – acceptance 8-month FN performance 1 year performance
Date, time and initials of last edit
22
HFST Collision Reduction 5-Year Average July - Dec
2015 July - Dec
Percent Reduction
Partial 2016 Jan – Mid February
All Collisions
17
1
94%
0
Wet Surface Collisions
15.2
0
100%
0
All Collisions
11
5
55%
0
Wet Surface Collisions
9.4
1
89%
0
I-90 Westbound
SR 526 Eastbound
23
Maintenance of HFST • Cracking – Low, medium or high severity cracking – Do nothing, do not install rubberized crack sealant on HFST
• Delamination – Small areas (5’x10’) – Patch with polymer materials and the bauxite aggregate used for HFST
• Potholes – Isolated spots can be repaired by cutting back to a well-bonded area and using had applied polymer resin and stone to blend the patch with existing material – Small areas (5’x10’) – Will need to patch with asphalt materials then polymer/bauxite on surface • This would be a two-phase patch with asphalt materials, then at least 30 days later, placement of the polymer materials
24
Unknowns • Can it be recycled? – Small quantities – Are the material properties relevant to HMA production? – Are there environmental factors that need to be considered?
• Precedence set using HFST – Once placed always placed? – Who pays for treatments between HMA rehab cycles.
• Maintenance repairs
25
Summary • The HFST countermeasure is most often used at locations with a higher friction demand (i.e. horizontal curves) and is most effective at sites with a history of wet weather collisions. The safety benefits of high friction surface treatments align with the Washington State Strategic Highway Safety Plan • Pavement condition criteria needs to be determined prior to installation • Preservation maintenance techniques can be used to address needed repairs although similar materials are preferred • The reduction of collisions using HFST has shown to be a valuable low-cost tool around the nation and within Washington State to mitigate lane departure accidents
26
Jeff Uhlmeyer WSDOT State Pavement Engineer
Rocky Mountain West Pavement Preservation Partnership Seattle, WA October 23-25, 2017
High Friction Surface Treatment - Background • HFS has gained popularity over the last decade in the United States for its crash reduction potential in locations which demand friction – Horizontal curves, locations with heavy braking such as approaches to intersections or crosswalks and/or steep grades
• Nine of the 39 states that have installed HFST have moved to aggressively deploy its use • Many states have documented high reductions in crashes at horizontal curves.
1. FHWA
2
High Friction Surface Treatment
• Durable, polish-resistant aggregate applied to an existing surface – Most common applications consist of calcined bauxite with a two-part epoxy resin
• Friction numbers are typically >70 – Average friction numbers on new HMA are generally in the 40 to 50 range
• Generally high benefit-cost ratio – Accidents drastically reduced
3
Mechanical Placement
4
Mechanical Placement
Mechanical/Manual Placement
5
Hand Placement
6
Hand Placement
7
WSDOT Projects •
2010 - SR 14 (WB On-Ramp at 164th Ave) Experimental Feature project – Two-lift mechanical installation – Third lift was placed in 2011
•
2014 - Bald Hills Rd. – Thurston County project – Manual installation using maintenance personnel
•
2015 - I-90 (WB On-Ramp at 148th St) and SR 526 (EB to I-5 SB On Ramp) placed under one contract
•
2016 - I-5 (SB On-Ramp to I-405), I-405 (WB On-Ramp to I-90), SR 14 (SB Off-Ramp to I-205), I-205 (3 Off-Ramps to SR 14) and SR 2 (Mainline) placed under three contracts
•
13 additional projects scheduled in the next three years.
8
SR 14 – 2013 (three years later)
9
SR 14 – 2016 (six years later)
10
Bald Hills Rd. – 2015 (one year later)
11
Bald Hills Rd. – 2016 (two yeas later)
12
Bald Hills Rd. – 2016 (two years later)
13
SR 526 to I-5 Ramp SB – 2016 (9 months later)
14
SR 526 to I-5 Ramp SB – 2016 (9 months later)
15
148th Street on ramp to I-90 WB – 2016 (9 months later)
16
148th Street on ramp to I-90 WB – 2016 (9 months later)
17
Issues Affecting HFST Performance • Raveling in roadway surface prior to installation • Existing longitudinal joint reflecting through • Existing cracks deteriorate after placement of HFST • Low density areas in HMA or distresses causing pop outs • Surface tension difference between HMA and resin compound • Are there alternate materials rather than Bauxite that would be effective (NCAT Study)
Therefore WSDOT developed criteria for HFST . . .
18
Criteria for HFST Projects
Pavements that are nearing their due year for rehabilitation should not receive HFST • HFST should only be placed on a pavement that is in relatively good condition (5 years or less in age but dependent on condition) – – – –
No structural-related cracking or rutting. No age-related alligator or longitudinal cracking Transverse cracking is okay provided the edges of the cracks are not raveled No cracks greater than ¼ inch in width
19
Criteria for HFST Projects (cont.)
– HFST should not be placed over longitudinal joints in the wheel path – The maximum rut depth should be less than 1/4 inch and at least 75% of the site should be less than 1/8 inch – No raveling, flushing or evidence of stripping – No drainage problems that result in water on the pavement surface during dry periods – Must have sufficient surface texture for a good bond
20
Friction Performance Bellevue / Eastgate – SB 148th to WB I90 Date tested Baseline FN before treatment Initial FN – after HFST 6-month performance 1 year FN performance 2 year FN performance
5/13/2015 7/7/2015 1/14/2016 8/16/2016 8/23/2017
Single lane ramp / ADT 11400 38.1 74.5 72.1 3.2% decline 71.4 1% decline 71.6 0.3% increase
Everett – EB 526 to SB I5 Baseline FN before treatment Initial FN – after HFST 6-month performance 1 year FN performance 2 year FN performance
Date, time and initials of last edit
Date tested 5/13/2015 7/7/2015 1/14/2016 8/16/2016 8/23/2017
Left lane (GP) / ADT 12650 38.7 82.9 76.6 7.6% decline 73.8 3.5% decline 67.6 8.4% decline
Right lane (HOV) / ADT 2400 39.7 86.0 77.5 77.8 71.9
10% decline 0.4% increase 7.6% decline
21
Friction Performance Factoria – SB 405 to WB I90 Baseline FN before treatment Initial FN – acceptance 8-month FN performance 1 year performance
Date tested 5/13/2015 8/16/2016 3/16/2017 8/23/2017
Left lane (GP) / ADT 20150 37.1 83.9 72.8 13% decline 69.8 4.1 decline
Right lane (HOV) / ADT 3090 43.0 87.1 79.3 9% decline 72.4 9.5% decline
Date tested 5/13/2015 8/16/2016 3/16/2017 8/23/2017
Left lane (GP) / ADT 18500 39.3 81.9 62.3 24% decline 63.4 1.7% increase
Right lane (GP) / ADT 7930 41.5 83.1 76.1 8% decline 71.6 6.3% decline
Lynnwood / Swamp Creek -SB I5 to SB 405 Baseline FN before treatment Initial FN – acceptance 8-month FN performance 1 year performance
Date, time and initials of last edit
22
HFST Collision Reduction 5-Year Average July - Dec
2015 July - Dec
Percent Reduction
Partial 2016 Jan – Mid February
All Collisions
17
1
94%
0
Wet Surface Collisions
15.2
0
100%
0
All Collisions
11
5
55%
0
Wet Surface Collisions
9.4
1
89%
0
I-90 Westbound
SR 526 Eastbound
23
Maintenance of HFST • Cracking – Low, medium or high severity cracking – Do nothing, do not install rubberized crack sealant on HFST
• Delamination – Small areas (5’x10’) – Patch with polymer materials and the bauxite aggregate used for HFST
• Potholes – Isolated spots can be repaired by cutting back to a well-bonded area and using had applied polymer resin and stone to blend the patch with existing material – Small areas (5’x10’) – Will need to patch with asphalt materials then polymer/bauxite on surface • This would be a two-phase patch with asphalt materials, then at least 30 days later, placement of the polymer materials
24
Unknowns • Can it be recycled? – Small quantities – Are the material properties relevant to HMA production? – Are there environmental factors that need to be considered?
• Precedence set using HFST – Once placed always placed? – Who pays for treatments between HMA rehab cycles.
• Maintenance repairs
25
Summary • The HFST countermeasure is most often used at locations with a higher friction demand (i.e. horizontal curves) and is most effective at sites with a history of wet weather collisions. The safety benefits of high friction surface treatments align with the Washington State Strategic Highway Safety Plan • Pavement condition criteria needs to be determined prior to installation • Preservation maintenance techniques can be used to address needed repairs although similar materials are preferred • The reduction of collisions using HFST has shown to be a valuable low-cost tool around the nation and within Washington State to mitigate lane departure accidents
26
