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.

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. What’s 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