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

1. NDOT’s Concrete Pavement-
Past, Present, & Future
Presented by:
Mick Syslo. P.E.
January 16, 2018
Nebraska Concrete
Paving Workshop

2. 1947

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. ASR (Alkali Silica Reactivity)
0 30% Limestone proved to be enough non-reactive
aggregate to “sweeten” the mix = no ASR

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. Archive Video – First Slip
form paving attempt

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

9. 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

10. 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

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
Nebraska’s Evaluation of Statewide Aggregate
Reactivity

12. 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

13. 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

14. 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

15. #
#
 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

16. #
#
 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

17. 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

18. 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

19. The Class R Combined
Aggregate Specification is to
have the Contractor develop a
combined aggregate gradation.

20. NDOR Future Challenges

21. 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.

22. 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

23. 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

24. Tools to get there
Step 3 – Soon

26. THANK YOU