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NDOT's Concrete Pavement: Past, Present & Future

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A presentation given during the 39th Annual NCPA Concrete Paving Workshop. By Mick Syslo, P.E.

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NDOT's Concrete Pavement: Past, Present & Future

  1. 1. NDOT’s Concrete Pavement- Past, Present, & Future Presented by: Mick Syslo. P.E. January 16, 2018 Nebraska Concrete Paving Workshop
  2. 2. 1947
  3. 3. 1947 Two Concrete specifications were developed 47B 47C 564 lbs Cement 70% Fine (Minus No.4)- Sand & Gravel Strength Workability 30% Coarse (Plus No.4)Limestone Gravel
  4. 4. ASR (Alkali Silica Reactivity) 0 30% Limestone proved to be enough non-reactive aggregate to “sweeten” the mix = no ASR
  5. 5. 1947 – 1970’s primarily Type I Cement / 30% limestone Then during the 70’s things began to change: Faster construction – Slip form paving Faster Set-up / Stiffer mixes Cement is beginning to be ground finer Environmental restrictions increase
  6. 6. Archive Video – First Slip form paving attempt
  7. 7. Paving continues, but in the mid 1990’s PCC Pavement designed to Last 50 Years Began to notice pavements less than 10 years old displaying severe deterioration
  8. 8. Concrete never deteriorates from a single cause usually there are multiple causes. Bryant Mahter The Better Projects: No Early Deterioration Moderate Air System Poor Drainage Non Doweled Pavement IPN or IPF Cement The Bad/Ugly Projects: Severe Early Deterioration Poor Air System Segregation Poor Drainage No Load Transfer Type I/II Cement with 17% Class C Fly Ash Replacement
  9. 9. 1985 Type I Cement Type I w/15% C ash 1995 17.5% IPN w/9% C Ash Type I/II w/17.5 F ash on Special Jobs Type I/II w/17% C Ash on Regular Jobs Type IP w/22%Total F ash blended 2002 17.5% IPN w/9% C Ash Type I/II w/17.5 F Ash Type I/II w/17% C Ash only on Small Projects Type IP w/22%Total F ash blended
  10. 10. Aggregate Type Location Platte River Grand Island Dry Pit Kimball Republican River Indianola North Platte River Scottsbluff South Platte River Ogallala Middle Loup River Thedford Little Blue River Fairbury Elkhorn River Norfolk Platte River Linoma Descripti on of Agg. Reactivity Moderat e Reactive Highly Reactive Very Highly Reactive Highly Reactive Moderat e Reactive Highly Reactive Moderat e Reactive Very Highly Nebraska’s Evaluation of Statewide Aggregate Reactivity
  11. 11. Aggregate Type Location Platte River Grand Island Dry Pit Kimball Republican River Indianola North Platte River Scottsbluff South Platte River Ogallala Middle Loup River Thedford Little Blue River Fairbury Elkhorn River Norfolk Platte River Linoma Descripti on of Agg. Reactivity Moderat e Reactive Highly Reactive Very Highly Reactive Highly Reactive Moderat e Reactive Highly Reactive Moderat e Reactive Very Highly (Table 6- AASHTO PP 65-10) Type I/II Cement Low Alkalinity Mim. Replacem ent Level of SCM Mim. Replacem ent Level of SCM Mitigate ASR 20 15 25 20 35 25 25 20 20 15 25 20 20 15 35 25 Nebraska's Spec Since Late 2004 IP with 25% Class F Nebraska’s Evaluation of Statewide Aggregate Reactivity Republican River Indianola’s Aggregate Non- Approved Aggregate
  12. 12. 1985 Type I Cement Type I w/15% C ash Late 2004-2005 IPN No longer available IPF/w 25% F ash Interground Type I/II w/25% F Ash Blended Total Alkali content not exceed 3 lbs/yds 2005-2013 For ALL PCC Jobs IPF Total F ash at rate of 25 + 2% IPFS (20% F – 20% GGBSF) 1995 17.5% IPN w/9% C Ash Type I/II w/17.5 F ash on Special Jobs Type I/II w/17% C Ash on Regular Jobs Type IP w/22%Total F ash blended 2002 17.5% IPN w/9% C Ash Type I/II w/17.5 F Ash Type I/II w/17% C Ash only on Small Projects Type IP w/22%Total F ash blended
  13. 13. Short Term Action: Eliminate the known causes of premature deterioration Long Term Plan: A comprehensive look at Concrete Pavement Design, Concrete Specifications, and QA/QC activities
  14. 14. # #  Provide a Solid Sub-Grade Stabilize cohesive soils with Lime, Fly Ash, CKD, Chemical, and geogrids  Provide Good Drainage Eliminate bathtub design using edge drains or french drains  Widen Slabs to Reduce Deterioration at Concrete/Asphalt Joints Developed a 30 foot design top  Provide Load Transfer at Joints Began designing pavement with dowel bars  Improve Ride quality Longitudinal tinning – Noise control Review & Adjust IRI - Smoothness
  15. 15. # #  Mitigate ASR  Pursue Supplementary Cementitious Material (SCM) combinations that are effective against ASR and improve permeability  Achieve Good Air System  Curing (paving & Structures)  Optimization of Aggregates Gradations
  16. 16. Plant Certification Program – Portable and Stationary Plant – Concrete Plant Technician • Certified batching operator Technician Certification Program – ACI Training – Pavement Smoothness Program – Portland Cement Sampler – Maturity Method Field Monitoring Material Verification Procedures – Random sampling for blended/interground cement • 750 tons Blended Cements (QA) - (oxides ratio) for ASR verification – QA/QC aggregates for gradations
  17. 17. Quality SCM’s EPA Regulations (Impact on the Future F-Ash Sources) Final Interground/ Blended Cement ASR For Concrete Applications:  NDOR allows the use of ASTM C 1697- Standard Specification for Blended Supplementary Cementitious Materials  NDOR allows the use IP, IS and IT cement in accordance with ASTM C595  Total Cement Replacement with SCM’s  20% min  40% max New 2014 Specification Interground/Blended Cements
  18. 18. The Class R Combined Aggregate Specification is to have the Contractor develop a combined aggregate gradation.
  19. 19. NDOR Future Challenges
  20. 20. Incompatible Admixture Combinations Final Air System Contractor’s Design’s need to make sure they have stable properties of the air-void system with different combinations of admixtures (Water Reducers and air entrainment) and cements.
  21. 21. A comprehensive look at Our Final Concrete Performance! We may be looking at different performance tests than we do today. Permeability Mechanical Properties Final hardened entrained air DIFFERENTINCENTIVES
  22. 22. Tools to get there Step 1 – Completed QA/QC for aggregates (Because Certification Program) IT Cements (Because New Technologies) More aggregate options (Class R gradation) Step 2 – Underway (some old, some new) QA/QC for fresh concrete Unit Weights & Air - front/behind paver Cement content May lower if within gradation parameter (Tarantula) Acceptance Strength, Thickness, Uniformity, Workmanship (no voids, cracking..) Incentive Smoothness, Production gradations
  23. 23. Tools to get there Step 3 – Soon
  24. 24. THANK YOU

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