two-lift paving - environmental performance

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A Two-Lift concrete Paving (2LCP) workshop was organized as a part of the Texas Department of Transportation (TxDOT) project 0-6749: Feasibility Study of Two-Lift Concrete Paving (2LCP). This workshop was conducted at the J. J. Pickle Research Campus (PRC), The University of Texas at Austin, Austin, TX on May 23rd, 2013. Dr. Jiong Hu, Texas State University, Research Supervisor, and Dr. David Fowler, The University of Texas at Austin, Co-Research Supervisor, co-chaired the workshop. The workshop offered the option of attending in person or remotely through webinar. Fifty-one attendees were present remotely or in person; 28 in person and 23 persons remotely.

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  • 1. UT - Two-Life Pavement workshop, Environmental benefits, Austin TX 05-2013 Environmental benefits of two-lift pavement A quantitative perspective based on life cycle assessment (LCA) Joep Meijer President of theRightenvironment In collaboration with the CP Tech Center

2. UT - Two-Life Pavement workshop, Environmental benefits, Austin TX 05-2013 Topics 1. What is LCA? 2. Our experience 3. Two-lift case 4. Whats next 3. UT - Two-Life Pavement workshop, Environmental benefits, Austin TX 05-2013 Life cycle assessment (LCA) LCA is a powerful tool for assessing the environmental performance of products, services or scenarios It is based on material and energy flows for processes and materials that together form a life cycle Resource A Resource B Production Assembly Use Maintenance Recycling 4. UT - Two-Life Pavement workshop, Environmental benefits, Austin TX 05-2013 Life cycle assessment (LCA) We use world-leading software and databases and apply ISO standards - ISO 14041 Goal and Scope Definition - ISO 14042 Inventory Analysis - ISO 14043 Interpretation - ISO 14044 Guidelines and principles - ISO 14025 Type III environmental declarations 5. UT - Two-Life Pavement workshop, Environmental benefits, Austin TX 05-2013 Goal and Scope Functional unit: what is to be assessed in terms of: - Amount - Unit - Functions - Requirements - Geographical considerations - Timeframe 6. UT - Two-Life Pavement workshop, Environmental benefits, Austin TX 05-2013 Inventory 7. UT - Two-Life Pavement workshop, Environmental benefits, Austin TX 05-2013 Impact Assessment A range of impact categories global warming (CO2-eq) depletion of non-renewables (Sb-eq) depletion of the ozone layer (CFC-11-eq) Acidification (SO2-eq) Eutrophication (PO4 3--eq) Summersmog (Ethylene-eq) aquatic ecotoxicity (CTUea) terrrestrial ecotoxicity (CTUet) human toxicity (CUTh) Energy (MJ) non-hazardous waste (kg) hazardous waste (kg) 8. UT - Two-Life Pavement workshop, Environmental benefits, Austin TX 05-2013 Impact Assessment The result is an Environmental profile 9. UT - Two-Life Pavement workshop, Environmental benefits, Austin TX 05-2013 Interpretation Major contributions give options for improvements 10. UT - Two-Life Pavement workshop, Environmental benefits, Austin TX 05-2013 Two-lift Kansas Comparison of: 1. Traditional 2. Two-lift 3. Optimized two-lift Together with Tom Van Dam, APTech Gary Fick, Trinity Construction Management Peter Taylor, CP Tech Center 11. UT - Two-Life Pavement workshop, Environmental benefits, Austin TX 05-2013 Two-lift Kansas Functional unit The material acquisition and construction of 1 km of a two lane highway with a total width of 7.4 m according to KDOT requirements in Kansas 12. UT - Two-Life Pavement workshop, Environmental benefits, Austin TX 05-2013 Two-lift Kansas 3.7 m 3.7 m Conventional concrete with a thickness of 340 mm 150 mm Cement Treated Base Traditional 3.7 m 3.7 m Tie bar: deformed No. 5 reinforcing bar (Grade 30), 915 mm long, spaced every 760 mm across the longitudinal contraction joint, formed by saw cutting D/3 Lower-lift of concrete with a thickness of 300 mm 150 mm Cement Treated Base Top-lift of concrete with a thickness of 40 Two-lift 13. UT - Two-Life Pavement workshop, Environmental benefits, Austin TX 05-2013 System boundaries 14. UT - Two-Life Pavement workshop, Environmental benefits, Austin TX 05-2013 Two-lift Kansas Key differences 1. Traditional Primary aggregate from OK for PCC Portland cement 2. Two-lift (same plus) CTB secondary aggregates on-site crusher Part fly ash in CTB and top lift 3. Optimized two-lift (same plus) CTB and bottom lift on-site crusher Fly ash in bottom lift 15. UT - Two-Life Pavement workshop, Environmental benefits, Austin TX 05-2013 Two-lift Kansas Limitations Average European data for materials, processes, allocation parameters just material acquisition and construction Look for relative differences not numbers 16. UT - Two-Life Pavement workshop, Environmental benefits, Austin TX 05-2013 Comparison Significant 1. Traditional 2. Two-lift 3. Optimized 17. UT - Two-Life Pavement workshop, Environmental benefits, Austin TX 05-2013 All recycling off-site, no on-site recycling Sensitivity analysis Significant 18. UT - Two-Life Pavement workshop, Environmental benefits, Austin TX 05-2013 Comparison Significant 1. Traditional 2. Two-lift 3. Optimized 19. UT - Two-Life Pavement workshop, Environmental benefits, Austin TX 05-2013 Sensitivity analysis All primary aggregates local, no recycled aggregate Significant 20. UT - Two-Life Pavement workshop, Environmental benefits, Austin TX 05-2013 Conclusions Two-lift shows great potential Reducing clinker content is a sound strategy Recycling pays off Optimizing logistics matters With equal distances for primary and secondary aggregates, handling proves to be discriminating (quarry vs. on-site or off-site recycling) 21. UT - Two-Life Pavement workshop, Environmental benefits, Austin TX 05-2013 LCA related lessons/limitations Always look at more than 1 indicator , not just energy(trade-offs) Do not forget we did not look at all life cycle stages (trade-offs) Always look for sensitivity analyses to test the robustness of certain parameters or assumptions We need more US based data 22. UT - Two-Life Pavement workshop, Environmental benefits, Austin TX 05-2013 Next steps Develop a framework Expand on current efforts to make a concrete and cement US database Feed with primary data Perform case studies 23. UT - Two-Life Pavement workshop, Environmental benefits, Austin TX 05-2013 Environmental benefits of two-lift pavement A quantitative perspective based on life cycle assessment (LCA) Joep Meijer President of theRightenvironment