SEAUPG ANNUAL MEETING NOVEMBER 14, 2013

Transcription

1 SEAUPG ANNUAL MEETING NOVEMBER 4, 3 Implementation of Semi Circular Bending Test Samuel Cooper III 3 Annual Meeting Southeastern Asphalt User Producer Group Novemer 4, 3 Baton Rouge, Louisiana Acknowledgements LTRC Asphalt Research Group Jeremy Icenogle, Patrick Frazier, Willie Gueho, Md. Kair, Bill King DOTD Materials La Participating Contractors LADOTD s current QA/QC practice relies upon: Gradation AC Content VFA, VMA, % Air Voids Moisture Susceptiility Test (Modified Lottman), and Roadway : Density, Smoothness But these volumetric properties alone are not adequate to reflect the pavement performance in the field. Must develop methods to evaluate pavement performance indicators In addition to current volumetric criteria Laoratory testing is required to evaluate the as uilt pavement qualities. These tests will screen materials prone to rutting, cracking and alternative moisture damage indicators. Create a Balanced Mixture Design Resistance What is a alanced mixture design? Process to ensure adequate resistance to rutting and cracking distress Two laoratory tests are proposed: : Loaded Wheel Tracking (LWT) Test.6 : Semi Circular Bend (SCB) Test Resistance Loaded Wheel Tracking (LWT) test as a measure of Semi Circular Bend (SCB) tests for intermediate

2 SEAUPG ANNUAL MEETING NOVEMBER 4, 3 LWT Specification Nominal Max., Size Agg. Type of Mix.5 inch (.5 mm).75 inch (9 mm). inch (5 mm) Incidental Paving ² Wearing Wearing Binder Binder Base ATB ⁸.5 inch (37.5 SMA mm) Base Wearing Level ³ A Asphalt Binder Tale 5, (3% minimum for Asphalt Treated ase (ATB), 6% min for SMA) Friction Rating ³ Tale 5 3 RAP, Max. % of Mix ⁴ Compacted Mix s 4 VMA, Min. %⁵ n/a.5 6. Air Voids, % ⁶ (.5 4.5);; (no limit for ATB) VFA, % ⁶ (69 8); no limit for ATB N initial 9% max. ⁷ (Gyrations) n/a 7 7 N design 96.5± % (Gyrations) N max 98 % max. (Gyrations) n/a LWT, max. rut design, # 5⁰ C Dust/Effective Asphalt Ratio, % Lift Thickness, inch @,. 3. (5 75) (65 ).5+ (65+) (+).5. LWT Specification Nominal Max., Size Agg. Type of Mix.5 inch (.5 mm).75 inch (9 mm). inch (5 mm) Incidental Paving ² Wearing Wearing Binder Binder Base ATB ⁸.5 inch (37.5 SMA mm) Base Wearing Level ³ A Asphalt Binder Tale 5, (3% minimum for Asphalt Treated ase (ATB), 6% min for SMA) Friction Rating ³ Tale 5 3 RAP, Max. % of Mix ⁴ Compacted Mix s 4 VMA, Min. %⁵ n/a.5 6. Air Voids, % ⁶ (.5 4.5);; (no limit for ATB) VFA, % ⁶ (69 8); no limit for ATB N initial 9% max. ⁷ (Gyrations) n/a 7 7 N design 96.5± % (Gyrations) N max 98 % max. (Gyrations) n/a LWT, max. rut design, # 5⁰ C Dust/Effective Asphalt Ratio, % Lift Thickness, inch @,. 3. (5 75) (65 ).5+ (65+) (+).5. Laoratory Experiment: LWT Test Laoratory Experiment: LWT Test Indicator Resistance to and Moisture Sensitivity Test Protocol AASHTO T34 5 C Loading Wheel Diameter: 3.5 mm (8 inch) Wheel Width: 47mm (.85 inch) Fixed Load: 73 N (58 ls) Rolling Speed:. km/hr Passing Rate: 5 passes/min Indicators Resistance to and Moisture Sensitivity Indicator: Plot Rut Depth vs Numer of Passes Report Rut Depth at, 5, 75,, 5, and Passes Moisture Sensitivity Indicator Determine Stripping Inflection Point Thepointwhereslopeof the line egins to steepen Balanced Specifications? Balanced Specifications? Loaded Wheel Tracking (LWT) test as a measure of Semi Circular Bend (SCB) tests for intermediate Loaded Wheel Tracking (LWT) test as a measure of Semi Circular Bend (SCB) tests for intermediate

3 P s P rd a notch P SEAUPG ANNUAL MEETING NOVEMBER 4, 3 Semi Circular Bend Test SCB Test Developed Circulated Indicator Resistance to Crack Propagation Test Protocol Mohammad et al. [4] 5 C Loading.5 mm/min vertical deformation The CriticalValue of Fracture Resistance, du da = sample thickness, a = notch depth, U = strain energy to failure Triplicate Specimens Tested: %CV <5 % SCB Sample Preparation Conventional SCB Test 5mm x 57mm Servo Hydraulic Test System Environmental Chamer Expensive Complicated Deformation Load Load.7.5 Original Data Max of Data set Fitted Curve Peak of Curve Deformation Force (Kn) Length(mm) du da 3

4 SEAUPG ANNUAL MEETING NOVEMBER 4, Original Data Max of Data set Fitted Curve Peak of Curve Force (Kn) Length(mm) du da * is controlled using an external environmental chamer Test Equipment 3 Pilot Project Descriptions Route LA 335 (H.949) LA 93 (H.6) LA 3 (H.89) LA 59 (H.95) US 8 (H.9536) LA 6 (H.43) DOTD Dist. 3 7 Description Lvl BC.5 Lvl F WC 3 Lvl BC Lvl WC Lvl BC Lvl WC 4 Lvl WC Lvl BC Lvl WC Lvl BC.5 Lvl FWC Analysis: Loaded Wheel Tester Analysis: Semi Circular Bend PG 64 PG 7 M PG 76 M PG 8 CRM. PG 64 PG 7 M PG 76 M PG 8 CRM Rut Passes, mm PG 64 Criteria Modified Binder Criteria Mixture Numer Jc, kj/m Mixture Numer 4

5 SEAUPG ANNUAL MEETING NOVEMBER 4, 3 Analysis: Balanced Design Jc, KJ/m..8 PG 64 PG 7 PG 76 PG 8 Modified Binder Criteria PG 64 Criteria Completion of Pilot Project Evaluation Evaluation of Field Cores Continued evaluation of the SCB test Validate Jc criteria for mixture design Communicate with other on going research projects: 4B 5 5 LWT Rut Depth, mm Thank You! 5