TechMRT. Texas Tech Center for Multidisciplinary Research in Transportation

Transcription

1 TechMRT Texas Tech Center for Multidisciplinary Research in Transportation

2 TxDOT Innovative Research Project Novel Material Systems for the Next Generation of Flexible Pavement Systems Dr. Sanjaya Senadheera Associate Professor of Civil Engineering Dept. of Civil, Environmental & Construction Engineering Director, TechMRT Texas Tech University

3 Research Emphasis: Innovations to Extend Service Life Traditional Significant Progress has been made in Pavements Materials Testing Design (M-E) Asset Management Innovative Research Extend Pavement Life using Novel Materials Adapt existing material technologies from within & outside highway industry landscape Founded on, Asphalt Aggregates Other Materials Distant Future Driverless Vehicles Electric Vehicles Novel Materials & Constructability Resource and Environmental Sustainability

4 TTU Research Team Research Support Team Total thus far Ronald Hedden Chemical Engineering Darryl James Mechanical Engineering Priyantha Jayawickrama Civil, Environmental & Construction Engineering 1 senior technician 7 postdoctoral fellows 10 graduate students 8 undergraduate students Rajesh Khare Chemical Engineering Daan Liang Civil, Environmental & Construction Engineering Hong Chao Zhang Industrial Engineering Sanjaya Senadheera Civil, Environmental & Construction Engineering Currently serving 1 senior technician 3 postdoctoral fellows 6 graduate students 5 undergraduate students

5 Interactions between Clusters Mechanical Eng. (James) Energy Engineering Energy Audit Energy capture Thermal Control Civil Eng. - Materials (Senadheera) Pavement temperature & pavement performance. Sustainable material systems Civil Eng. - Geotech (Jayawickrama) Geotechnical engineering Mitigation of subgrade effects Soil-structure interaction Industrial Eng. (Zhang) Sustainability assessment Resources, Environment, Energy & Water Life-Cycle Assessment Chemical Eng. (Hedden, Khare) Novel asphalt modification Phase change materials Molecular simulation Construction Eng. (Liang) Constructability Life-Cycle Cost Cost-Benefit Analysis

6 Control of Pavement Temperature Using Phase-Change Materials (PCMs) Basic premise: Incorporation of microencapsulated PCMs into flexible pavements for reducing summertime temperatures and mitigating rutting problems. Current status: PCM approach is successful in reducing or delaying temperature maxima in the surface layer. Potential Payoffs: PCM-containing pavements could be implemented in sections of roadways that have rutting problems in order to reduce maintenance costs, extend pavement lifetime.

7 Polymer-Modification Binders using Polyolefins Objective: Identify and Characterize Cost-Effective Modifiers for Asphalt Binders Polyolefins more cost-effective than traditional modifiers Does not require addition of sulfur for stability PP/PE copolymer is fully compatible with asphalts at mixing temperatures (325 ) Results show high-temperature performance improvement by at least one grade Bulk PP/PE copolymer Spherulites (~25 m) in meltcrystallized PP/PE copolymer 85% Polypropylene / 15% Polyethylene Copolymer (Crystallizable) Crystalline fibers and sheets form as the binder cools, providing a PG PG PP/PE Fluorescence image stabilizing and reinforcing effects. The binders separate into asphaltene-rich (green fluorescent) and maltene-rich phases upon cooling, much like SBS-modified binders. 100 m 100 m 200 m

8 Molecular Simulation of Asphalt Binders with Polymers and PCM Atactic Polypropylene (APP) Polymer Additive Neat asphalt (AAM-1) APP modified asphalt AAM-1 Asphalt with Polymer and PCM Schematics of encapsulated PCM modified asphalt system

9 Major Findings - Heat Transfer Modeling Embedded PCM in Asphalt Concrete Layer Temp. drop 19.3 C; = 0.3 Temperature in Surface Layer for Various PCM volume Contents Embedded PCM + Enhanced Heat Transfer PCM % by Vol Keff 1 T max 63.3 C Maximum Surface Temperature Drop for PCM % and Thermal Conductivity Combinations

10 Exploratory Field Tests

11 Life-Cycle Cost Analysis and Sustainable Life-Cycle Assessment (LCA) Pavement designer has two tools to evaluate alternatives; Life-Cyele Cost Analysis End of Life Material Production Construction Environmental Life- Cycle Assessment Rehabilitation Service

12 Thank You! Sanjaya Senadheera Texas Tech University