Timing of Preservation Treatments AWS
Timing of Preservation Treatments & Surface Treatments QA Construction Best Practices Tech Briefs Pavement Engineering & Science Program University of Nevada, Reno 2017 Rocky Mountain West Pavement Preservation Partnership Meeting Seattle, WA – October 25, 2017 www.wrsc.unr.edu
Slide No. 1
Regional Transportation Commission of Washoe County (RTC)
EFFECTIVENESS & OPTIMUM TIME FOR SINGLE & SEQUENTIAL APPLICATIONS OF SLURRY SEAL
www.wrsc.unr.edu
Slide No. 2
Introduction • Slurry seal has been used on county’s pavements for long time. • No guidelines to when to apply slurry seal. • Slurry seal was applied at different times of pavement life. • as early as right after construction • to as late as 9 years after.
www.wrsc.unr.edu
Slide No. 3
Introduction • Questions to be answered: – How effective is the pavement preservation program? – Is the cost justifiable? – How to increase the benefit of using pavement preservation by optimizing the time of application?
www.wrsc.unr.edu
Slide No. 4
Introduction • Phase I: Collect & evaluate historical performance data of asphalt pavements with single application of slurry seal • Phase II: Collect & evaluate historical performance data of asphalt pavements with sequential applications of slurry seal
www.wrsc.unr.edu
Slide No. 5
Slurry Seal Treatment - Applied on DGHMA with 1/2 or 3/4 inch NMAS. - Slurry seals followed guidelines contained in International Slurry Surfacing Association (ISSA) Publication A105. - Emulsion asphalts generally consisted of latex modified cationic quick set with a min of 3% latex rubber by weight of the binder following agencies requirements. - Majority of evaluated slurry sealed pavement sections received the slurry seal between June & September.
www.wrsc.unr.edu
Slide No. 6
Performance Evaluation (Single Application) Performance Life ∼ 2 yrs
100 80
Performance Life ∼ 3 yrs
60 PCI
Extension in Pavement Service Life ∼ 2 yrs
40 20 0
0
2
4
6
8
10
12
14
16
18
20
Single SS applied at 0, 1, 3, 5, 7, or 9 yrs after construction
Age in Years New Construction Slurry Seal at year 7 www.wrsc.unr.edu
Slurry Seal at year 3 Slide No. 7
Performance Evaluation (Sequential Application) 1st slurry seal @ year 3
Present Condition Index (PCI)
100
3 yrs
4.0 yrs
2nd slurry seal @ year 7
80 Predicted Do-Nothing performance curve (Using performance models developed in Phase I)
60 40 20 0
0
2
4
3.5 yrs
Predicted SS at year 3 performance curve (Using performance models developed in Phase I
6
8
10
1st SS at either yr 0, 1, 3 or 5 2nd SS at either yr 7 or 9
12
14
16
Age in Years
www.wrsc.unr.edu
Slide No. 8
18
20
Findings: Performance Life/Extension in Pavement Life Single Application
• Performance life ranged between 2 & 4 yrs. – Except when slurry seal was applied at year 0 & 1, performance life < 1 year.
• Except few cases, pavement service life was not extended by a single application – Though a better ride quality was provided.
www.wrsc.unr.edu
Slide No. 9
Findings: Performance Life/Extension in Pavement Life Sequential Application • Sequential Application 0 OL-0-7 OL-0-9 OL-1-7 OL-1-9 OL-3-7 OL-3-9 OL-5-9 NC-0-7 NC-0-9 NC-1-7 NC-1-9 NC-3-7 NC-3-9 NC-5-9 www.wrsc.unr.edu
Years 2
1 1.1 0.7 0.6
1.5
1.7
3 Performance life of 2nd SS
2.2
Extension in pavement service life
1.7 1.8 2.4 2.3
3.3 3.3 3.5 2.7
3.2 3.3
1.2 0.4 0.9
1.7 3
0.5
3.3 2.5 1.7
2.2 Slide No. 10
3.2
3.6
4
Findings: Benefit Cost Analysis Single Application Overlay (Do Nothing)
100
Slurry Seal
90 80 70 60
B0
PCI
50
B
40 30 20 10 0 0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
Age (years)
Benefit Cost Ratio = B / C www.wrsc.unr.edu
Slide No. 11
15
16
Pavement Condition Index (PCI)
Findings: Benefit Cost Analysis Sequential Application 100
NC-C-3-9 NC-3-9
80
B
B0
60 40 20 0 0
2
4
6
8
10
12
14
16
Age in Years
Benefit-Cost Ratio = B / C www.wrsc.unr.edu
Slide No. 12
18
20
New Construction
20 15 10 5 0
0
NC-Arterial (A)
1
3
5
7
9
Year of Slurry Seal Application NC-Collector (B)
NC-Residential (C)
Benefit-Cost Ratio (x1000)
Benefit-Cost Ratio (x1000)
Findings: Benefit Cost Analysis Single Application Overlay
20 15 10 5 0
0
OL-Arterial (A)
1
3
5
7
Year of Slurry Seal Application OL-Collector (B)
OL-Residential (C)
Optimum time for application of a Single Slurry Seal: Newly constructed pavements: 3 years after construction (PCI of 87-90). Pavements subjected to overlays: 3-5 years after construction (PCI of 85-87). www.wrsc.unr.edu
9
Slide No. 13
Findings: Benefit Cost Analysis Sequential Application
www.wrsc.unr.edu
Slide No. 14
Optimum Time of Application: Implementation
Construction Type
Recommended Threshold PCI Values 1st Slurry Seal Application
2nd Slurry Seal Application
New AC
87-90
86
AC Overlay
85-87
77
www.wrsc.unr.edu
100 85 70 55 40 25 10 0
Slide No. 15
PCI Rating Excellent Very Good Good Fair Poor Very Poor Failed
Project 15Q2-E3-1
CHIP SEALS, SLURRY SEALS, MICRO SURFACING & THIN ASPHALT CONCRETE OVERLAYS QUALITY ASSURANCE CONSTRUCTION BEST PRACTICES TECH BRIEFS
www.wrsc.unr.edu
Slide No. 16
Acknowledgment for Funding & Support • Federal Highway Administration (FHWA) • Nevada Department of Transportation (NDOT)
www.wrsc.unr.edu
Slide No. 17
A. Project Information: Research Team • Pavement Engineering & Science Program; Western Regional Superpave Center ( ) at UNR o Elie Y. Hajj (PI), Peter E. Sebaaly (Co-PI), and Adam J.T. Hand o Lauren Graham (Graduate Research Assistant)
• National Center for Asphalt Technology (
)
o Mike Heitzman and Nam Tran
• Consultant o Dean Weitzel www.wrsc.unr.edu
Slide No. 18
A. Project Information (Cont’d): National Experts Panel Name
Title
Organization
Anita Bush
Chief Maintenance and Asset Management Engineer
Nevada DOT
James Gray/ Bryan Cawley
Construction Management Team Leader
FHWA
James Gray
Preservation and Maintenance Engineer
FHWA
Jon A. Epps
Executive Associate Director
Texas A&M Transportation Institute
Gerard (Jerry) Geib
Research Operations Engineer
Minnesota DOT
Tim Harrawood
Manager Southern Contracting Division
Vance Brothers, Inc.
Jim Moulthrop
Senior Consultant
Fugro Consultants, Inc.
Chuck Suszko
Chief Office of Construction Engineering
California DOT
Richard Turner
Pavement Engineer
Charleston County, SC
US DOT (1); State Public Agency (4); Academia (1); Local Agency (1); Industry (2) www.wrsc.unr.edu
Slide No. 19
A. Project Information (Cont’d): Overall Project Objectives 1) Identify factors that will lead to a “best-practice” construction QA program; 2) Prepare a technology brief for each of the treatments based on the successful experience from lead highway agencies; & 3) Prepare example specifications, testing procedures, and other information that SHAs can use. The QA Construction Best Practices are to be developed based on observed/ identified successful experiences
www.wrsc.unr.edu
Slide No. 20
A. Project Information (Cont’d): Tasks • Task 1: Organize Experts Panel, Select Factors and Conduct State Survey. • Task 2: Collect Survey Data (Contact Lead States), Prepare Tech Briefs. • Task 3: Develop Technical Guides and Reports.
www.wrsc.unr.edu
Slide No. 21
B. Surveys & Phone Interviews
Tier 1 Survey
• Tier 1 web survey was conducted (short – 5 questions, information to identify agencies for Tier 2 follow-up survey). • Received 182 responses (124–owner agencies & 58–contractors). – Thank you to: AASHTO Subcommittee on Construction, AASHTO Subcommittee on Maintenance, ISSA, LTAP/TTAP, NAPA (ActionNews e-newsletter).
• As a result, 11 agencies & 8 contractors selected for Tier 2 follow-up phone interviews focused on obtaining detailed information on: – – – – – –
Standard construction specifications Construction QA programs Entity responsible of QC for materials & inspection including equipment Early-life performance issues and potential causes Aspects of proper and improper construction practices Etc.
www.wrsc.unr.edu
Slide No. 22
B. Surveys & Phone Interviews
Tier 2 Survey – Example Results KEY ASPECTS OF CONSTRUCTION RESULTING IN GOOD EXPERIENCES (10 AGENCIES TOTAL)
Number of Respondents
Equipment calibration Personnel cert. Verification of materials/application rates Surface prep Fog Seal Other (includes crack sealing, using pre-coated chips, small-truck chip spreaders, good inspection, proper surface/air temperatures, test strips and tack coats)
8 6 4 2 0
www.wrsc.unr.edu
7
6 3
4 2
Chip Seal
1
2
2 2
5 3
2 0
Slurry Seal
3 1
4 2 0
1
Microsurfacing Slide No. 23
1
5
5
3 0
Thin Asphalt Overlay
B. Surveys & Phone Interviews
Tier 2 Survey – Example Results (Cont’d) AREAS OF QA NEEDING IMPROVEMENT (10 AGENCIES TOTAL)
Number of Respondents
Materials Inspection Better Communication Training Other (includes updating specs, continuous improvement and in-place validation) 8 6
6 4 2 0
www.wrsc.unr.edu
2
1
1
Chip Seal
1
0
0
1
2
Slurry Seal
4
3 1
0
2
1
2 0
Microsurfacing Slide No. 24
3 1
2
Thin Asphalt Overlay
B. Surveys & Phone Interviews
Tier 2 Survey – Example Results (Cont’d) PRIMARY CAUSE(S) OF EARLY DISTRESSES (11 AGENCIES TOTAL)
Number of Respondents
Incorrect project selection Materials/mix design issues Climate/temperature Poor Workmanship Poor Construction Other (includes early-traffic opening, winter damage, poor surface prep, lack of experience and underlying pavement distresses)
8 6
5
6
4 2 0
www.wrsc.unr.edu
1
2
Chip Seal
3 3 1 1
2 0
1
Slurry Seal
2
1 1
2
3 3
3 1 1
Microsurfacing Slide No. 25
0
2
1
2
Thin Asphalt Overlay
B. Surveys & Phone Interviews
Lead Agencies
• Lead agencies were identified. • Representatives of the selected lead agencies were further interviewed & documents were collected. • Some contractors who have worked for the agencies were also interviewed in an effort to collect additional information.
www.wrsc.unr.edu
Slide No. 26
Chip Seal Slurry Seal Thin Lift AC Overlay
OK
Chip Seal and Micro Surfacing Slurry Seal and Micro Surfacing Chip Seal, Slurry Seal, Micro Surfacing, and Thin Lift AC Overlay
Treatment Chip Seal Slurry Seal Micro-surfacing Thin Asphalt Concrete Overlay www.wrsc.unr.edu
Agencies California, Minnesota, Spokane Co., Texas California, City of Columbus (Ohio), Virginia California, Minnesota, Virginia California, Florida, Michigan, Ohio Slide No. 27
C. Technical Guides & Reports
www.wrsc.unr.edu
Slide No. 28
C. Technical Guides & Reports (Cont’d) • Drafting of final report undergoing. – To be sent to the panel for review & comments
• Work will begin soon on writing tech briefs.
www.wrsc.unr.edu
Slide No. 29
Turning Asphalt Green…..
“The Hard Work Puts You Where The Good Luck Can Find You”
By Mike Bergin
www.wrsc.unr.edu
Slide No. 31
Slide No. 1
Regional Transportation Commission of Washoe County (RTC)
EFFECTIVENESS & OPTIMUM TIME FOR SINGLE & SEQUENTIAL APPLICATIONS OF SLURRY SEAL
www.wrsc.unr.edu
Slide No. 2
Introduction • Slurry seal has been used on county’s pavements for long time. • No guidelines to when to apply slurry seal. • Slurry seal was applied at different times of pavement life. • as early as right after construction • to as late as 9 years after.
www.wrsc.unr.edu
Slide No. 3
Introduction • Questions to be answered: – How effective is the pavement preservation program? – Is the cost justifiable? – How to increase the benefit of using pavement preservation by optimizing the time of application?
www.wrsc.unr.edu
Slide No. 4
Introduction • Phase I: Collect & evaluate historical performance data of asphalt pavements with single application of slurry seal • Phase II: Collect & evaluate historical performance data of asphalt pavements with sequential applications of slurry seal
www.wrsc.unr.edu
Slide No. 5
Slurry Seal Treatment - Applied on DGHMA with 1/2 or 3/4 inch NMAS. - Slurry seals followed guidelines contained in International Slurry Surfacing Association (ISSA) Publication A105. - Emulsion asphalts generally consisted of latex modified cationic quick set with a min of 3% latex rubber by weight of the binder following agencies requirements. - Majority of evaluated slurry sealed pavement sections received the slurry seal between June & September.
www.wrsc.unr.edu
Slide No. 6
Performance Evaluation (Single Application) Performance Life ∼ 2 yrs
100 80
Performance Life ∼ 3 yrs
60 PCI
Extension in Pavement Service Life ∼ 2 yrs
40 20 0
0
2
4
6
8
10
12
14
16
18
20
Single SS applied at 0, 1, 3, 5, 7, or 9 yrs after construction
Age in Years New Construction Slurry Seal at year 7 www.wrsc.unr.edu
Slurry Seal at year 3 Slide No. 7
Performance Evaluation (Sequential Application) 1st slurry seal @ year 3
Present Condition Index (PCI)
100
3 yrs
4.0 yrs
2nd slurry seal @ year 7
80 Predicted Do-Nothing performance curve (Using performance models developed in Phase I)
60 40 20 0
0
2
4
3.5 yrs
Predicted SS at year 3 performance curve (Using performance models developed in Phase I
6
8
10
1st SS at either yr 0, 1, 3 or 5 2nd SS at either yr 7 or 9
12
14
16
Age in Years
www.wrsc.unr.edu
Slide No. 8
18
20
Findings: Performance Life/Extension in Pavement Life Single Application
• Performance life ranged between 2 & 4 yrs. – Except when slurry seal was applied at year 0 & 1, performance life < 1 year.
• Except few cases, pavement service life was not extended by a single application – Though a better ride quality was provided.
www.wrsc.unr.edu
Slide No. 9
Findings: Performance Life/Extension in Pavement Life Sequential Application • Sequential Application 0 OL-0-7 OL-0-9 OL-1-7 OL-1-9 OL-3-7 OL-3-9 OL-5-9 NC-0-7 NC-0-9 NC-1-7 NC-1-9 NC-3-7 NC-3-9 NC-5-9 www.wrsc.unr.edu
Years 2
1 1.1 0.7 0.6
1.5
1.7
3 Performance life of 2nd SS
2.2
Extension in pavement service life
1.7 1.8 2.4 2.3
3.3 3.3 3.5 2.7
3.2 3.3
1.2 0.4 0.9
1.7 3
0.5
3.3 2.5 1.7
2.2 Slide No. 10
3.2
3.6
4
Findings: Benefit Cost Analysis Single Application Overlay (Do Nothing)
100
Slurry Seal
90 80 70 60
B0
PCI
50
B
40 30 20 10 0 0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
Age (years)
Benefit Cost Ratio = B / C www.wrsc.unr.edu
Slide No. 11
15
16
Pavement Condition Index (PCI)
Findings: Benefit Cost Analysis Sequential Application 100
NC-C-3-9 NC-3-9
80
B
B0
60 40 20 0 0
2
4
6
8
10
12
14
16
Age in Years
Benefit-Cost Ratio = B / C www.wrsc.unr.edu
Slide No. 12
18
20
New Construction
20 15 10 5 0
0
NC-Arterial (A)
1
3
5
7
9
Year of Slurry Seal Application NC-Collector (B)
NC-Residential (C)
Benefit-Cost Ratio (x1000)
Benefit-Cost Ratio (x1000)
Findings: Benefit Cost Analysis Single Application Overlay
20 15 10 5 0
0
OL-Arterial (A)
1
3
5
7
Year of Slurry Seal Application OL-Collector (B)
OL-Residential (C)
Optimum time for application of a Single Slurry Seal: Newly constructed pavements: 3 years after construction (PCI of 87-90). Pavements subjected to overlays: 3-5 years after construction (PCI of 85-87). www.wrsc.unr.edu
9
Slide No. 13
Findings: Benefit Cost Analysis Sequential Application
www.wrsc.unr.edu
Slide No. 14
Optimum Time of Application: Implementation
Construction Type
Recommended Threshold PCI Values 1st Slurry Seal Application
2nd Slurry Seal Application
New AC
87-90
86
AC Overlay
85-87
77
www.wrsc.unr.edu
100 85 70 55 40 25 10 0
Slide No. 15
PCI Rating Excellent Very Good Good Fair Poor Very Poor Failed
Project 15Q2-E3-1
CHIP SEALS, SLURRY SEALS, MICRO SURFACING & THIN ASPHALT CONCRETE OVERLAYS QUALITY ASSURANCE CONSTRUCTION BEST PRACTICES TECH BRIEFS
www.wrsc.unr.edu
Slide No. 16
Acknowledgment for Funding & Support • Federal Highway Administration (FHWA) • Nevada Department of Transportation (NDOT)
www.wrsc.unr.edu
Slide No. 17
A. Project Information: Research Team • Pavement Engineering & Science Program; Western Regional Superpave Center ( ) at UNR o Elie Y. Hajj (PI), Peter E. Sebaaly (Co-PI), and Adam J.T. Hand o Lauren Graham (Graduate Research Assistant)
• National Center for Asphalt Technology (
)
o Mike Heitzman and Nam Tran
• Consultant o Dean Weitzel www.wrsc.unr.edu
Slide No. 18
A. Project Information (Cont’d): National Experts Panel Name
Title
Organization
Anita Bush
Chief Maintenance and Asset Management Engineer
Nevada DOT
James Gray/ Bryan Cawley
Construction Management Team Leader
FHWA
James Gray
Preservation and Maintenance Engineer
FHWA
Jon A. Epps
Executive Associate Director
Texas A&M Transportation Institute
Gerard (Jerry) Geib
Research Operations Engineer
Minnesota DOT
Tim Harrawood
Manager Southern Contracting Division
Vance Brothers, Inc.
Jim Moulthrop
Senior Consultant
Fugro Consultants, Inc.
Chuck Suszko
Chief Office of Construction Engineering
California DOT
Richard Turner
Pavement Engineer
Charleston County, SC
US DOT (1); State Public Agency (4); Academia (1); Local Agency (1); Industry (2) www.wrsc.unr.edu
Slide No. 19
A. Project Information (Cont’d): Overall Project Objectives 1) Identify factors that will lead to a “best-practice” construction QA program; 2) Prepare a technology brief for each of the treatments based on the successful experience from lead highway agencies; & 3) Prepare example specifications, testing procedures, and other information that SHAs can use. The QA Construction Best Practices are to be developed based on observed/ identified successful experiences
www.wrsc.unr.edu
Slide No. 20
A. Project Information (Cont’d): Tasks • Task 1: Organize Experts Panel, Select Factors and Conduct State Survey. • Task 2: Collect Survey Data (Contact Lead States), Prepare Tech Briefs. • Task 3: Develop Technical Guides and Reports.
www.wrsc.unr.edu
Slide No. 21
B. Surveys & Phone Interviews
Tier 1 Survey
• Tier 1 web survey was conducted (short – 5 questions, information to identify agencies for Tier 2 follow-up survey). • Received 182 responses (124–owner agencies & 58–contractors). – Thank you to: AASHTO Subcommittee on Construction, AASHTO Subcommittee on Maintenance, ISSA, LTAP/TTAP, NAPA (ActionNews e-newsletter).
• As a result, 11 agencies & 8 contractors selected for Tier 2 follow-up phone interviews focused on obtaining detailed information on: – – – – – –
Standard construction specifications Construction QA programs Entity responsible of QC for materials & inspection including equipment Early-life performance issues and potential causes Aspects of proper and improper construction practices Etc.
www.wrsc.unr.edu
Slide No. 22
B. Surveys & Phone Interviews
Tier 2 Survey – Example Results KEY ASPECTS OF CONSTRUCTION RESULTING IN GOOD EXPERIENCES (10 AGENCIES TOTAL)
Number of Respondents
Equipment calibration Personnel cert. Verification of materials/application rates Surface prep Fog Seal Other (includes crack sealing, using pre-coated chips, small-truck chip spreaders, good inspection, proper surface/air temperatures, test strips and tack coats)
8 6 4 2 0
www.wrsc.unr.edu
7
6 3
4 2
Chip Seal
1
2
2 2
5 3
2 0
Slurry Seal
3 1
4 2 0
1
Microsurfacing Slide No. 23
1
5
5
3 0
Thin Asphalt Overlay
B. Surveys & Phone Interviews
Tier 2 Survey – Example Results (Cont’d) AREAS OF QA NEEDING IMPROVEMENT (10 AGENCIES TOTAL)
Number of Respondents
Materials Inspection Better Communication Training Other (includes updating specs, continuous improvement and in-place validation) 8 6
6 4 2 0
www.wrsc.unr.edu
2
1
1
Chip Seal
1
0
0
1
2
Slurry Seal
4
3 1
0
2
1
2 0
Microsurfacing Slide No. 24
3 1
2
Thin Asphalt Overlay
B. Surveys & Phone Interviews
Tier 2 Survey – Example Results (Cont’d) PRIMARY CAUSE(S) OF EARLY DISTRESSES (11 AGENCIES TOTAL)
Number of Respondents
Incorrect project selection Materials/mix design issues Climate/temperature Poor Workmanship Poor Construction Other (includes early-traffic opening, winter damage, poor surface prep, lack of experience and underlying pavement distresses)
8 6
5
6
4 2 0
www.wrsc.unr.edu
1
2
Chip Seal
3 3 1 1
2 0
1
Slurry Seal
2
1 1
2
3 3
3 1 1
Microsurfacing Slide No. 25
0
2
1
2
Thin Asphalt Overlay
B. Surveys & Phone Interviews
Lead Agencies
• Lead agencies were identified. • Representatives of the selected lead agencies were further interviewed & documents were collected. • Some contractors who have worked for the agencies were also interviewed in an effort to collect additional information.
www.wrsc.unr.edu
Slide No. 26
Chip Seal Slurry Seal Thin Lift AC Overlay
OK
Chip Seal and Micro Surfacing Slurry Seal and Micro Surfacing Chip Seal, Slurry Seal, Micro Surfacing, and Thin Lift AC Overlay
Treatment Chip Seal Slurry Seal Micro-surfacing Thin Asphalt Concrete Overlay www.wrsc.unr.edu
Agencies California, Minnesota, Spokane Co., Texas California, City of Columbus (Ohio), Virginia California, Minnesota, Virginia California, Florida, Michigan, Ohio Slide No. 27
C. Technical Guides & Reports
www.wrsc.unr.edu
Slide No. 28
C. Technical Guides & Reports (Cont’d) • Drafting of final report undergoing. – To be sent to the panel for review & comments
• Work will begin soon on writing tech briefs.
www.wrsc.unr.edu
Slide No. 29
Turning Asphalt Green…..
“The Hard Work Puts You Where The Good Luck Can Find You”
By Mike Bergin
www.wrsc.unr.edu
Slide No. 31
