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Two Lift Concrete Paving
TxDOT Perspective
Andy Naranjo, P.E.
• Use of Manufactured Sands
• Use of Coarse Aggregates with High CoTE
values
Use of Local Materials
Use of Manufactured Sands
Manufactured Sands
Natural River Sand 
Depletion
TxDOT Spec Limits
• Concrete subject to direct 
traffic requires the use of 
fine aggregates or blends 
to have a A.I. gre...
Use of High CoTE Concrete
High CoTE
Aggregates
CoTE Data
3.0
3.5
4.0
4.5
5.0
5.5
6.0
6.5
CoTE, microstrain/F
Coarse Aggregate CoTE Values
25% above Limit
Acceptable for ...
San Antonio ACI June 27, 2012
Spalling in Concrete Pavement
Classification of TxDOT CRCP Distresses 
0‐6274 Project Level Performance Database for Rigid Pavement in Texas, Phase II 
...
Money Spent to Solve Problem
• Research
– Over $2 million for the past 25 years
• Maintenance
– The Houston District has s...
Lower CoTE Concrete
Or 
Concrete with Natural 
Sands
Higher CoTE
Concrete
Or
Concrete with Man. 
Sands
Questions
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Two-Lift Paving - TxDOT Perspective

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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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Two-Lift Paving - TxDOT Perspective

  1. 1. Two Lift Concrete Paving TxDOT Perspective Andy Naranjo, P.E.
  2. 2. • Use of Manufactured Sands • Use of Coarse Aggregates with High CoTE values Use of Local Materials
  3. 3. Use of Manufactured Sands
  4. 4. Manufactured Sands Natural River Sand  Depletion
  5. 5. TxDOT Spec Limits • Concrete subject to direct  traffic requires the use of  fine aggregates or blends  to have a A.I. greater than  60%. • Limits the use of Man.  Sands
  6. 6. Use of High CoTE Concrete
  7. 7. High CoTE Aggregates
  8. 8. CoTE Data 3.0 3.5 4.0 4.5 5.0 5.5 6.0 6.5 CoTE, microstrain/F Coarse Aggregate CoTE Values 25% above Limit Acceptable for  use in CRCP Unacceptable for  use in CRCP
  9. 9. San Antonio ACI June 27, 2012 Spalling in Concrete Pavement
  10. 10. Classification of TxDOT CRCP Distresses  0‐6274 Project Level Performance Database for Rigid Pavement in Texas, Phase II  San Antonio ACI June 27, 2012
  11. 11. Money Spent to Solve Problem • Research – Over $2 million for the past 25 years • Maintenance – The Houston District has spent: • $41+ million to repair CRCP spalling • $400+ million to place bonded overlays • Spalling virtually eliminated since the CoTE requirement began use in HOU ~10 years ago –Restricts the use of local aggregates
  12. 12. Lower CoTE Concrete Or  Concrete with Natural  Sands Higher CoTE Concrete Or Concrete with Man.  Sands
  13. 13. Questions

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