Development of Performance Curves for Whitetoppings in Minnesota - Research Update
April 19th, 2016 Tom Burnham, Tim Andersen
Safer, Smarter, Sustainable Pavements through Innovative Research
Agenda
• Objectives
• Study tasks and timeline
• Field condition survey results
• Preliminary performance curves
• Associated research
Acknowledgements
• Chago Heurta – Student worker
• American Engineering Testing
• MnDOT, Q3, and County Traffic Control Forces
• MnDOT Concrete Office
• Tim Andersen - Technical Liaison
Objective: Development of Performance Curves
for Whitetoppings in Minnesota
• Review performance in Minnesota • Develop performance curves for MnDOT Pavement
Management System • Identify best practices for design and timing of
maintenance • Improve project selection (CPTech Center study)
Study Tasks and Timeline • Task 1 - Literature search and project database (Aug 2015)
– Task 1 report available for review • Task 2 - Field condition survey – Part 1A and 1B (Mar 2016)
– Task 2 report available for review • Task 3 - Data Analysis – Part 1 (Jun 2016) • Task 4 - Interim Report (July 2016) • Task 5 - Field condition survey - Part 2 (Dec 2016) • Task 6 - Data Analysis – Part 2 (Feb 2017) • Task 7 - Draft final report (Mar 2017) • Task 8 - Final report (May 2017)
Task 1 Literature Search • Very limited performance curves available
– Louisiana DOT, 13.5 years, 4’x4’panels, 4” PCC
Xingwei Chen (2015)
Task 1 Project Database • Breakdown
– 5 MnDOT projects • TH30 (1993) • TH212 (2009) • I-35 (2009) • TH56 (2010) • TH24 (2014)
– 21 MnROAD sections
– 20 County projects (oldest built in 2009)
Task 1 Conclusion
Developing performance curves will be challenging due to lack of older projects in Minnesota
(MnROAD data will help!)
Task 2 Field Condition Surveys
• Data collected on 21 statewide projects – GPR for thickness variation – Profiled for IRI [9 projects revisited in Nov 2015] – Initial visual distress survey – 3 core samples
• Assess bond quality • GPR thickness calibration • HMA assessment
Task 2 Field Observations • Most projects are good to very good condition
– Most are still “young” – Some longitudinal cracking – A few buckled panels (McLeod County)
• Transverse reflective cracking not prevalent
– I-35 project: early cracks remain tight – Matching PCC joints to HMA cracks not necessary
Task 2 Field Observations • Undoweled transverse joints can developing faulting
when subject to heavy truck volumes/loads – Noticeable faulting on TH22 Olmsted County project
• 4 years old, 6.5” thick, 12’x12’ panels, undoweled joints • Very heavy truck volumes • No cracked panels
– Attempts to match overlay joints to underlying HMA cracks seems to lead to early faulting
• Full-depth vertical movement – With smaller joint spacings, not all joints appear to deploy
• Leads to 12’ effective panel lengths
• Little to no maintenance on most projects
Task 2 MnROAD Observations Faulting of joints
6’ x 6’ doweled vs undoweled 10’ x 12’ faulted (and cracked)
Faulting Mechanism NCHRP 338 (Rasmussen and Rozycki), 2004
– Hypothesis for joint faulting = permanent deformation of HMA
Current TPF 5-269 UBOL design pooled fund (Vandenbossche), 2014
– Observed permanent deformation in HMA interlayers in lab
Task 2 MnROAD Observations Potential design option?
12’ x 6’ do not crack transversely (Cell 614, plate dowels)
Task 2 Field Observations GPR testing revealed typical variations in concrete overlay and asphalt thickness
Task 2 Field Observations Core samples revealed various PCC/Asphalt
bonding conditions
Task 3 Data Analysis - Part 1 Population by age (includes MnROAD)
Task 3 Data Analysis - Part 1 Population by thickness (includes MnROAD)
Task 3 Data Analysis - Part 1 Population by panel size
Task 3 Data Analysis - Part 1 • Other population details
– Remaining asphalt thicknesses from 3” to 14” – 20.5/46 projects with unsealed joints – No major projects with structural fibers
• MnROAD Cells 160, 162 (built in 2013)
Interstate traffic
Next steps
• Further breakdown and analysis to determine variability of RQI
• Surface rating will be determined for each project • Preliminary performance curves will be generated and
published in Interim Report • One or more profile measurements and distress
surveys will be done on projects during summer/fall of 2016
12 millions CESALS in 2010
500,000 CESALS
Associated Research
Thin Whitetopping Selection Procedures
Research Team: Dale Harrington, Julie Vandenbossche, Gary Fick
working under Peter Taylor, CPTech Center
Questions and Discussion