Presented at the 37th Annual NCPA Concrete Paving Workshop Presenter: Gary Fick

1. Tools to Improve PCC Smoothness
During Construction (R06E)
Date: January 19, 2016
Gary Fick

2. 2
Real-Time Smoothness
What is it?
An integrated system
of profile data
collection sensors and
processing software
that provides real-time
profile feedback to the
contractor.

3. 3
Real-Time Smoothness
SHRP2 Implementation Support
RTS Implementation Support Activities
Objective: Routine use of RTS technology by agencies and
contractors who routinely construct PCC pavement.

4. 4
Real-Time Smoothness
SHRP2 Implementation Support
RTS Implementation Support Activities
Task 1: Equipment Loan Program (2015 and 2016)
 Full use of an RTS system for two weeks
 On-site technical support and training
 Budget allows for eleven equipment loans
 Projects with a minimum of 10 consecutive mainline paving days
(more is preferable)
 Contractor or agency should commit to providing daily QA
profiles during the equipment loan
 Contact gfick@trinity-cms.com if interested

5. 5
Real-Time Smoothness
SHRP2 Implementation Support
RTS Implementation Support Activities
Task 2: Regional Showcase (Open House)
 One day classroom presentations with an on-site RTS
demonstration
 In conjunction with an equipment loan project
 Travel expenses are covered for up to 10 agency participants

6. 6
Real-Time Smoothness
SHRP2 Implementation Support
RTS Implementation Support Activities
Task 3: Workshops
 Four hour workshops – contact gfick@trinity-cms.com
 Tentative agenda
1. Importance of Pavement Smoothness
2. Fundamentals of Pavement Smoothness Measurement
3. RTS Measurement Technology and Practices
4. Fundamentals of Ride Quality and Pavement Profile
Analysis
5. Current Practices for Concrete Pavement IRI Specifications
6. Best Practices for Concrete Paving Operations
7. Using RTS Technology to Improve Concrete Pavement
Smoothness

7. 7
Real-Time Smoothness
SHRP2 Implementation Support
RTS Implementation Support Activities
Task 4: Documentation of Results/Case Studies
 Synthesis of contractors’ experience
 Case study – Comparing real-time measurements to QA results
 Case study – Long-term performance of RTS
 Documentation of equipment loans and lessons learned

8. 8
Real-Time Smoothness
SHRP2 Implementation Support
RTS Implementation Support Activities
Task 5: Specification Refinement
 QC approach
 Process improvement
Task 6: Outreach Materials
 Quick field reference guide (pocket reference)
 Brochures
 Project updates (30 minute briefings)

9. 9
Reasons for Using RTS Equipment
• Reduce disincentives
• Increase incentives
• Anticipated change in smoothness acceptance
requirements
• PI to IRI
• Change in localized roughness specification limits

10. 10
Real-Time Smoothness
Benefits of identifying construction artifacts in real-
time
Opportunity to correct objectionable profile features caused by:
 Stringline disturbance
 Padline variability
 Non-uniformity of concrete
 …

11. 11
Real-Time Smoothness
Benefits of identifying the impact of process changes
in real-time
Validation of adjustments in 1 hour vs. 12 to 24 hours:
 Hydraulic sensitivity relative to machine control input (stringline
and stringless)
 Vibrator frequencies
 Paving speed
 Concrete head
 Concrete mixture proportions
 …

12. 12
RTS Systems – Which One is Best?
• They both do the same thing - the correct
question is, “which one is best for me?”
• Factors to consider:
 Ease of mounting and switching between multiple pavers
 Field ruggedness
 Familiarity with Ames lightweight
profiler systems
 Laser vs. ultrasonic sensors

13. 13
RTS Mounting Locations
• Typically center of each driving lane
• Adjust this for special situations, when tuning the
paver:
 Tie bar insertion issues
 One side of the paver is consistently rougher
 Cross-slope changes

14. 14
RTS Mounting Locations

15. 15
RTS Systems:
Daily Setup and Shutdown
• Start-up - approximately 5 minutes
 Install sensors and DMI
 Connect cables
 Input starting station and direction
 Start the system
• Shut-down – approximately 5 minutes
 Stop the system
 Download data to a USB drive
 Disconnect cables
 Remove sensors and DMI

16. 16
RTS Systems:
Daily Setup and Shutdown

17. 17
Ten Commandments of Concrete
Pavement Smoothness (circa 1988)
Source: ACPA Best Practices for Constructing Smooth Concrete Pavements
Credit: Chapin Cipherd, CMI Corp.

18. 18
21st Century Approach
The “Sweet Spot”
Mixture
Factors
Paving
Factors
Human
Factors

19. 19
Mixture Factors
• Combined gradation
• Between batch uniformity
• Uniform delivery of concrete

20. 20
Combined Gradation
Remember the purpose of an optimized gradation:
• Economically combining aggregate particles to achieve the desired
objectives of:
 Reduced paste content
 Improved workability
 Durability
• An optimized mixture must be workable in the field to achieve
durability
• The Tarantula curve was developed concurrently with a lab test that
evaluates a concrete mixture’s response to vibration

21. 21
Between Batch Uniformity
Consistent combined gradation and water content
• Scales in tolerance
• Uniform stockpile moistures
• Eliminate stockpile segregation

22. 22
Uniform Delivery of Concrete
Translates to minimizing paver stops
• Plant production capacity must be able to feed the
paver

23. 23
Paving Factors
• Track line
• Stringline/Stringless model
• Paver setup
 Draft/Lead
 Sensitivities
 Vibrator frequency
 Vibrator height
 Float pan
• Concrete head
• Curing and texturing

24. 24
Human Factors
• Training
• Experience
• Communication
• Empowerment

25. 25
Using RTS Systems
• Step 1 – Establish a baseline
• Monitor results for 1 to 2 days
• Keep processes static, but make ordinary adjustments
 Observe typical responses to the ordinary adjustments
• Mixture
• Vibrators
• Speed
• Head
• Stops
• Etc.

26. 26
Using RTS Systems
• The RTS results are higher than the QC hardened
profiles – what’s up with that?
• Don’t panic
• Just focus on making the RTS results better (lower IRI)
• QC profiles will improve as well

27. 27
Using RTS Systems
• Step 2 – Pick the low hanging fruit
• Eliminate large events that cause excessive
localized roughness
• Stringline/stringless interference
• Paver stops
• Padline issues
• Etc.

28. 28
Localized Roughness Events
• Stringless system interference

29. 29
Localized Roughness Events
• Running the paver out of concrete

30. 30
Localized Roughness Events
• Stopping the paver

31. 31
Using RTS Systems
• Step 3 – Adjust the paving process to improve
overall smoothness
• Maintain a consistent head
• Lead/draft - setup the paver as flat as possible
• Sensitivities
• Vibrators (height and frequency)
• Mixture
• Paver operation
• Paving speed

32. 32
Overall Smoothness
• Eliminating big events gave us a new “baseline” to
adjust from
• Systematically make changes in small increments
• Get a minimum of 0.1 mile with consistent paving (no big
events) and then evaluate if the adjustment made things
smoother
• Continue adjusting in small increments and evaluating every
0.1 mile

33. 33
Overall Smoothness
• Stay focused and incredible things can happen
• Over a mile per day – average IRI = 28 in/mi

34. 34
Using RTS Systems
• Step 4 – Identify repeating features using a PSD plot
and adjust processes when possible
• Joints
• CRCP bar supports
• Dumping/Spreading loads

35. 35
Real-Time Smoothness
SHRP2 Implementation Support
Questions and Discussion