Chelsea Hanson  (Advisor: Eshan V. Dave  Department of Civil Engineering, University of Minnesota Duluth INTRODUCTION and MOTIVATIONRESEARCH APPROACH DISCUSSIONS OF RESULTS CONCLUSIONS and FUTURE RESEARCH Thermal cracking is a severe problem in cold climate regions At present, no pavement performance test is required as asphalt mix acceptance criteria in MnDOT 2360 specifications Implementation of laboratory performance test can improve reliability of asphalt mix performance Comprehensive database of existing mix designs and pavement cracking performance is needed: Investigation of effects of mix design parameters on pavement performance Determine which laboratory tests provide reliable measure of pavement performance First phase of study narrowed lab tests down to indirect tensile strength from TSR and fracture energy from disk shaped compact tension (DCT) Compilation of mix design and pavement performance database followed by statistical analysis allows to determine effects of mix volumetrics and design parameters on field cracking performance PG binder grade, PG spread, and PG LT showed correlation with indirect tensile strengths in both single and multiple variable analysis TSR found not to be correlated to mix volumetrics or binder grade Preliminary analysis of interstate highways in Minnesota showed minimal effects of asphalt binder content on transverse cracking More analysis is currently underway: Further analyze all mix design and pavement management data Include mixes that contain RAP, RAS, etc. to quantify effects of reclaimed and recycled materials on pavement performance Conduct statistical analysis to quantify correlation between mix design parameters and pavement performance Determine effective laboratory performance test for acceptance of asphalt mix design criteria Implement performance test into agency specifications Obtain asphalt mix design and field performance data from Minnesota Department of Transportation Combine data and develop comprehensive databases in Microsoft Access Generate queries to combine mix design data for statistical analysis Conduct statistical analysis using SAS software for both single and multiple variable dependence Analyze the effects of mix design parameters on pavement field performance (For example PG grade, VMA, etc.) Indirect Tensile Strength for AASHTO T-283 (TSR) Initial single variable analysis shows no direct correlation between most mix design parameters and indirect tensile strength of mix from TSR (Dry strength), except binder grade and PG spread Multiple variable analysis shows significance of dry strength with pairing of some variables SAS analysis showed statistical significance with mix parameters compared to volumetrics Preliminary results for pavement management sections for interstate highways in Minnesota show no clear trend between transverse cracking rates and asphalt amount and mix volumetrics Single Variable Analysis Mix Parameter Dependence to Mix Strength? AFTno Design Air Voidsno Actual Air Voidsno NMASno % AC (Ignition and Extracted)no VMA and VFAno Binder Gradeyes Traffic Levelyes Multiple (Grouped) Variable Analysis Mix Parameters Dependence to Mix Strength? PG Grade and VMA Extractedno PG Grade and VMA Ignitionno PG Grade and %AC (Extraction)no PG Grade and %AC (Ignition)yes PG Grade and AFT Adjustedyes Data Source Amount of Available Data Material Data Records12,293 LIMS Database32,515 TSR Database2,545 Pavement Management58,416 Mix Design Traffic Level, Mix Size, Binder Type, % Recycled Material, Mix Volumetrics, Dry Strength, Wet Strength, TSR Mix Design Traffic Level, Mix Size, Binder Type, % Recycled Material, Mix Volumetrics, Dry Strength, Wet Strength, TSR Field Performance from Pavement Management Section Location, Traffic Information, Cracking Performance Field Performance from Pavement Management Section Location, Traffic Information, Cracking Performance Database Microsoft Access Database Microsoft Access Statistical Analysis LS Means Analysis, SAS Software Statistical Analysis LS Means Analysis, SAS Software -Effect of Mix Parameters on Pavement Performance -Suitability of lab test as Performance Measure -Effect of Mix Parameters on Pavement Performance -Suitability of lab test as Performance Measure