Industry/PennDOT Initiative On Performance Testing. AN UPDATE January 22, 2019

Industry/PennDOT Initiative On Performance Testing AN UPDATE January 22, 2019

Outline Testing Modes A Review of Semi-Circular Bend (SCB) Test PA Industry Initiative on SCB Results & Observations Next Steps 2

Outline Testing Modes A Review of Semi-Circular Bend (SCB) Test PA Industry Initiative on SCB Results & Observations Next Steps 3

LABORATORY PERFORMANCE TESTS Modes of Testing

Loading Modes Uniaxial Compression Uniaxial Direct Tension Indirect Tension Triaxial Compression Shear Flexure

Laboratory Tests on Asphalt Concrete Uniaxial Tension Uniaxial Compression Cyclic Uniaxial Tension/Compression

Laboratory Tests on Asphalt Concrete Flexural Beam Test 3-Point Bending Test 4-Point Bending Test

Laboratory Tests on Asphalt Concrete Triaxial Test Indirect Tensile Test

Laboratory Tests on Asphalt Concrete European Standard Test

Outline Testing Modes A Review of Semi-Circular Bend (SCB) Test PA Industry Initiative on SCB Results & Observations Next Steps 10

SCB Test Apply on Rocks (Initial Application) Photo Source: Lim et al. 1984 11

SCB Test Applied to Rocks SCB Testing of Granite Rock Photo Source: Dynamic Behavior of Materials, Vol.1 12

SCB Test Applied to Rocks Compression-Induced Fracture Surfaces and Failure Mechanism Photo Source: Advances in Materials Science and Engineering Vol. 2014, Article 814504 13

SCB Test Setup Applied Load Notc h Suppor t 120 mm 150 mm Suppor t Specimen Thickness: 50 mm Notch Depth: 15 mm Notch Width: 1.5 mm 14

Parameters Used For Evaluation 5000 4500 Load (N) 4000 3500 3000 2500 2000 Slope @ 50% Peak Load Peak Load (P ) Slope @ Inflection Point (m) 1500 1000 500 Work of Fracture (W ) Critical Displacement 0 0 1 2 3 4 5 6 7 8 Displacement (mm) Fracture Energy G W B L B: Specimen Thickness L: Ligament Length Flexibility Index FI A A: Constant G abs m Stiffness Index Slope @ 50% Peak Load in Pre-Peak Curve 15

Louisiana SCB Method (J Integral Concept) Notch Depth: 25.4 mm Notch Depth: 31.8 mm Notch Depth: 38.0 mm Strain Energy to Failure Plot Source: Mohammad et al. 2012 16

Advantages of SCB Test Specimen Easily Prepared Using SGC or Field Cores Four Specimens from One Compacted Mix or Core Easy to Perform and Simple to Analyze Possible To Perform Test Using Marshall Type Stability Tester 17

Test Loading Rate and Temperature Current Protocols: 50 mm/min (too fast, not enough data points, higher COV) 0.5 mm/min (too slow, affected by creep) Findings: Loading rate between 5 to 20 mm/min will minimize the effect of creep, and provide a reasonable range for FI for long term aged mix. Test at 20 C to simulate average PA climate 18

Specimen Preparation SGC Specimen or Field Cores Cut to Ensure Minimum AV Gradient Obtain Density Condition Specimens Conduct Test 150 mm 20 mm 50 mm 50 mm 20 mm 150 mm 19

Specimen Preparation and Testing Specimen after Cutting and Ready for Testing Test Sensitivity Strain Rate Temperature Sample Preparation (Voids) Sample Curing Specimen before and after Testing 20

Load, Newtons 3500 3000 2500 2000 1500 1000 500 Typical Load vs Displacement Curves 3 Replicates, PG 58 28, 25 C 50 mm/min 25 mm/min 5 mm/min 1 mm/min 0 0 1 2 3 4 5 6 7 8 Displacement (mm) Lower strain Rate lower peak & flatter post peak slope same or higher F.I. 21

Outline Testing Modes A Review of Semi-Circular Bend (SCB) Test PA Industry Initiative on SCB Results & Observations Next Steps 22

How Did it Start? Move to Performance Testing for Mix Optimization Initiated by Asphalt Quality Improvement Committee and PAPA Industry Expressing Interest in Participating 23

Purpose of the Effort Impetus to Performance Testing Investigate Performance of PA Mixes in SCB Develop A Database of SCB Test Results Evaluate Sensitivity of the PA Mixes to the Test Variables Evaluate Correlation with Field Performance 9

Mix Criteria and Variables Air Void: 5.5% (Final SCB Specimen) Design Binder Content (and +0.5%) Mixes with various RAP higher contents Short/Long term aging effects Laboratory mixes and plant produced mixes NMAS: 4.75, 9.5mm, 19mm, 25mm 10

Summary of SGC Plugs Tested (total of 85) Source Mix Origin Mix Condition NMAS, mm Binder Grade # of Binder Contents RAP 01 Plant Long 9.5 64-22 1 15 02 Plant/Lab Short/Long 9.5 64-22 6 0 03 Plant Short/Long 9.5 64-22 2 0 04 Plant/Lab Long 9.5 64-22 1 0 05 Plant/Lab Short 4.75, 9.5, 64-22 25 76-22 4 0, 15, 30 06 Plant/Lab Short/Long 9.5 64-22 6 15 07 Lab Long 2 0, 15 08 Lab Short 9.5, 19 64-22 4 10, 15 09 Lab Long 9.5 64-22 76-22 1 15, 20 10 Lab Short/Long 9.5 64-22 76-22 2 15, 20 11 Lab Long 9.5 64-22 1 0, 15 26

Statistics TOTAL NUMBER OF SGC PLUGS RECEIVED = 85 NMAS, mm 4.75 9.5 Number of Plugs in each Category RAP Content, % 4 3 3 2 2 8 0 10 15 19 2 19 20 25 75 25 30 52 27

Outline Testing Modes A Review of Semi-Circular Bend (SCB) Test PA Industry Initiative on SCB Results & Observations Next Steps 28

Air Voids Reported vs. NECEPT Measured Air Void Comparison (SGC plugs as received) 8.0 7.5 NECEPT Measured AV, % 7.0 6.5 6.0 5.5 5.0 4.5 4.0 4.0 4.5 5.0 5.5 6.0 6.5 7.0 7.5 8.0 Reported AV, % 29

Asphalt Content Number of Plugs in each BC Category 16 15 14 12 11 Number of Plugs 10 8 6 4 2 3 4 2 2 2 4 8 2 3 7 4 7 2 2 5 2 0 Binder Content, % 30

Air Void Distribution Overall Data Range and Distribution: Air Void (After Cutting) Air Void, % 9 8 7 6 5 4 3 2 1 0 STOA Target: 5 6% Average: 5.2% LTOA 9 Air Void, % 8 7 6 5 4 3 2 Target: 5 6% Average: 5.4% 1 0 31

Peak Load Distribution Overall Data Range and Distribution: Peak Load Peak Load, N 6000 5000 4000 3000 2000 1000 0 STOA Average: 3337 N Peak Load, N 6000 5000 4000 3000 2000 LTOA Average: 4123.7 N 1000 0 32

Flexibility Index Distribution Overall Data Range and Distribution: Flexibility Index 60 STOA Flexibility Index 50 40 30 20 Median 7 Average: 8.1 10 0 35 LTOA Flexibility Index 30 25 20 15 10 Median 5 or 6 Average: 4.6 5 0 33

Post Peak Slope Distribution 0 Specimen Number 0 50 100 150 200 250 300 350-5 -10 Post Peak Slope -15-20 -25-30 -35-40 -45 34

General Observations (G.O.) 1. Higher AC Content higher F.I. 2. Higher RAP content lower F.I. 3. Longer aging lower F.I. 4. Plant mix has higher F.I. than lab mix 5 Higher voids higher F.I. 6 SMA mix delivers high F.I. 7. Finer mix with high BC higher F.I. 35

General Observations (G.O.) 1. Higher AC Content higher F.I. 2. Higher RAP content lower F.I. 3. Longer aging lower F.I. 4. Plant mix has higher F.I. than lab mix 5. Higher voids higher F.I. 6. SMA mix delivers high F.I. 7. Finer mix with high BC higher F.I. 36

G.O. #1 Producer F: Plant Mix 10 9 8 STOA LTOA Plant Mix STOA: Short Term Oven Aging LTOA: Long Term Oven Aging Flexibility Index 7 6 5 4 3 2 1 0 4.0 4.5 5.0 5.5 6.0 6.5 7.0 Binder Content, % JMF = 5.9% Post Min Pbe JMF = 5.2% Pre Min Pbe 37

G.O. #1 Producer F: Lab Mix 6 STOA Lab Mix Flexibility Index 5 4 3 2 LTOA STOA: Short Term Oven Aging LTOA: Long Term Oven Aging Plant:Lab 1:0.5 1 0 4.0 4.5 5.0 5.5 6.0 6.5 7.0 Binder Content, % 38

G.O. #1 Producer H-1 30 25 NMAS=9.5 NMAS=4.75 NMAS=25 PG76 22 Flexibility Index 20 15 10 5 30%RAP, Plant 15%RAP 0 4.0 4.5 5.0 5.5 6.0 6.5 7.0 Binder Content, % 39

General Observations (G.O.) 1. Higher AC Content higher F.I. 2. Higher RAP content lower F.I. 3. Longer aging lower F.I. 4. Plant mix has higher F.I. than lab mix 5. Higher voids higher F.I. 6. SMA mix delivers high F.I. 7. Finer mix with high BC higher F.I. 40

G.O. #2 Producer G-1 Flexibility Index 7 6 5 4 3 2 1 0 STOA LTOA 10 15 20 25 RAP Content, % STOA: Short Term Oven Aging LTOA: Long Term Oven Aging : PG64-22 : PG76-22 1:0.67 STOA:LTOA 1:0.67-0.76 15%:20%RAP 41

G.O. #2 Producer G-2 7 Flexibility Index 6 5 4 3 2 STOA LTOA Overlap with PG64 22 STOA: Short Term Oven Aging LTOA: Long Term Oven Aging : PG64-22 : PG76-22 1:0.15-0.25 STOA:LTOA 1 1:0.33-0.67 15%:20%RAP 0 10 15 20 25 RAP Content, % 42

G.O. #2 Producer H-3 All Specimens were STOA 30 25 NMAS=9.5 NMAS=4.75 NMAS=25 Flexibility Index 20 15 10 5 0 0 5 10 15 20 25 30 35 40 RAP Content, % 43

G.O. #2 All Producers 70 60 STOA-With RAP STOA-No RAP 50 Flexibility Index 40 30 20 10 0 0 1,000 2,000 3,000 4,000 5,000 6,000 7,000 8,000 9,000 10,000 Stiffness Index, Newtons/mm 44

G.O. #2 40 All Producers 35 LTOA-With RAP LTOA-No RAP 30 Flexibility Index 25 20 15 10 5 0 0 1,000 2,000 3,000 4,000 5,000 6,000 7,000 8,000 9,000 10,000 Stiffness Index, Newtons/mm 45

G.O. #2 All Producers Stiffness Index, Newtons/mm 0 0 1,000 2,000 3,000 4,000 5,000 6,000 7,000 8,000 9,000-2 -4 Post Peak Slope -6-8 -10-12 -14-16 -18 STOA-With RAP STOA-No RAP 46

G.O. #2 All Producers Stiffness Index, Newtons/mm 0 0 1,000 2,000 3,000 4,000 5,000 6,000 7,000 8,000 9,000 10,000-5 -10 Post Peak Slope -15-20 -25-30 -35-40 -45 LTOA-With RAP LTOA-No RAP 47

General Observations (G.O.) 1. Higher AC Content higher F.I. 2. Higher RAP content lower F.I. 3. Longer aging lower F.I. 4. Plant mix has higher F.I. than lab mix 5. Higher voids higher F.I. 6. SMA mix delivers high F.I. 7. Finer mix with high BC higher F.I. 48

G.O. #3 Producer L-1 18 16 STOA 0%RAP LTOA 0%RAP STOA 15%RAP LTOA 15%RAP Flexibility Index 14 12 10 8 6 4 2 0 5.8 5.9 6.0 6.1 6.2 6.3 6.4 6.5 6.6 6.7 Binder Content, % 1:0.5 STOA:LTOA 1:0.55 0%:15%RAP 49

G.O. #3 Producer I 25 20 STOA/LTOA 9.5mm PG64-22 Multiple BC 0/15%RAP LTOA FI 15 10 y = 0.2694x + 0.9484 R² = 0.6801 5 0 0 5 10 15 20 25 STOA FI 50

G.O. #3 All Producers 70 60 STOA LTOA 50 Flexibility Index 40 30 20 10 0 0 1,000 2,000 3,000 4,000 5,000 6,000 7,000 8,000 9,000 10,000 Stiffness Index, Newtons/mm 51

General Observations (G.O.) 1. Higher AC Content higher F.I. 2. Higher RAP content lower F.I. 3. Longer aging lower F.I. 4. Plant mix has higher F.I. than lab mix 5. Higher voids higher F.I. 6. SMA mix delivers high F.I. 7. Finer mix with high BC higher F.I. 52

G.O. #4 Producer F 10 STOA 9 LTOA 8 Plant Mix STOA: Short Term Oven Aging LTOA: Long Term Oven Aging Flexibility Index 7 6 5 4 3 2 1 0 4.0 4.5 5.0 5.5 6.0 6.5 7.0 Binder Content, % JMF = 5.9% Post Min Pbe JMF = 5.2% Pre Min Pbe 53

G.O. #4 Producer F (Continued) 6 STOA Lab Mix Flexibility Index 5 4 3 2 LTOA STOA: Short Term Oven Aging LTOA: Long Term Oven Aging Plant:Lab 1:0.5 1 0 4.0 4.5 5.0 5.5 6.0 6.5 7.0 Binder Content, % 54

G.O. #4 Producer E 30 25 Plant Lab Lab Plant? LTOA 9.5mm PG64-22 5.5%BC 0/15/25%RA P 20 Flexibility Index 15 10 5 0 0 5 10 15 20 25 30 RAP Content, % 55

General Observations (G.O.) 1. Higher AC Content higher F.I. 2. Higher RAP content lower F.I. 3. Longer aging lower F.I. 4. Plant mix has higher F.I. than lab mix 5. Higher voids higher F.I. 6. SMA mix delivers high F.I. 7. Finer mix with high BC higher F.I. 56

G.O. #5 All Producers Specimen Air Void, % 70 60 1 2 3 4 5 6 7 8 9 target Flexibility Index 50 40 30 20 10 0 57

G.O. #5 All Producers Specimen Air Void, % 7,000 1 2 3 4 5 6 7 8 9 6,000 Peak Load, Newtons 5,000 4,000 3,000 2,000 1,000 0 58

General Observations (G.O.) 1. Higher AC Content higher F.I. 2. Higher RAP content lower F.I. 3. Longer aging lower F.I. 4. Plant mix has higher F.I. than lab mix 5. Higher voids higher F.I. 6. SMA mix delivers high F.I. 7. Finer mix with high BC higher F.I. 59

G.O. #6 Producer H: Lab Produced Flexibility Index 40 30 20 10 0 What effect do we see? Binder Content RAP Polymer BC: 5.9% AV: AV: 4.5% 4.7% PG64 22 + 15%RAP STOA 9.5mm PG64-22/PG76-22 BC: 6.4% BC: 6.9% Specimen 1 5.9/6.4/6.9%BC 0/15%RAP BC: 6.9% Specimen 2 AV: 4.7% AV: 5.3% PG76 22 + 0%RAP 60

General Observations (G.O.) 1. Higher AC Content higher F.I. 2. Higher RAP content lower F.I. 3. Longer aging lower F.I. 4. Plant mix has higher F.I. than lab mix 5. Higher voids higher F.I. 6. SMA mix delivers high F.I. 7. Finer mix with high BC higher F.I. 61

G.O. #7 Producer H: Lab Produced Flexibility Index 25 20 15 10 5 0%RAP Specimen 1 AV: 5.0% STOA 4.75mm PG64-22 0%RAP Specimen 2 6.8%BC 0/15%RAP 15%RAP (6.1% Virgin Binder) AV: 5.0% AV: 4.7% 0 62

Outline Testing Modes A Review of Semi Circular Bend (SCB) Test PA Industry Initiative on SCB Results & Observations Next Steps 63

Where could we go next? 1. Gather information from producers on details of aging protocol and specimen preparation 2. More SCB testing to fill in some of the gaps. 3. Test mix(es) with proven good long term performance. 4. Test to determine long term effects of rejuvenators. 5. Track mix performance in the field to verify lab predictions. 64

To contact Pennsylvania Asphalt Pavement Association 3544 North Progress Avenue, Suite 100, Harrisburg, PA 17110-9647 www.pa-asphalt.org 717-657-1881 Charles C Goodhart, Executive Director cgoodhart@pa-asphalt.org Gary L Hoffman P.E., Director of Technical Services gary@pa-asphalt.org Committed To: Safe, Smooth, Sustainable, Long Lasting Pavements! 65