Jagan Gudimettla PE ATI Inc Consultant to the Federal Highway Administration Office of Asset Management Pavements and Construction In early 80s FHWA saw technology gap Between research and practice ID: 638717
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Slide1
FHWA Mobile Concrete Trailer (MCT)
Jagan Gudimettla, P.E.
ATI Inc., Consultant to the
Federal Highway Administration
Office of Asset Management, Pavements, and ConstructionSlide2
In early 80’s FHWA saw technology gap
Between research and practiceImplemented Technology Transfer ProgramShare informationShowcase new developmentsEducate and train
FHWA Mobile Concrete TrailerSlide3
Technology Transfer to SHA’s
Field demos on active projects
Equipment loan Training of staffConferences and workshops
Mission
FHWA Mobile Concrete TrailerSlide4
Field Visits
Active field project for a two week period
Traditional and Innovative testing Data in control chart formatMCT Typical Activities
Kick-Off Meeting
Testing
Testing
Week 1Slide5
Field Visits
Active field project for a two week period
Traditional and Innovative testing Data in control chart formatMCT Typical Activities
TestingTesting
Open House
Week 2Slide6
Field Visits
Close out meeting with the state DOT, FHWA division office and contractor (prior to departure)
Summary report (3-5 months after field visit)A free QA workshop using the field visit dataMCT Typical Activities
Close Out
QA WorkshopSlide7
Training
One on one training to DOT engineers and technicians
Side by side comparison of new technologiesMCT Typical ActivitiesSlide8
Conferences
National Conferences (ACI, TRB,
ISCP, etc)State DOT / Industry conferencesProvide speakersSpecialized WorkshopsTechnical Assistance
MCT Typical ActivitiesSlide9
Equipment Loan Program
Multiple pieces
Few weeks to a few monthsVery successful
MCT Typical ActivitiesSlide10
MCT Focus Areas
AASHTOWare
Pavement ME Design
Quality Assurance
Performance Engineered Mixtures
Nondestructive/In-situ Tests
FHWA Mobile Concrete Trailer
Performance Related
Specifications
SustainabilitySlide11
Are we testing the right quality characteristics??
What do we test for acceptance
Slump
Air Content
StrengthSlide12
Test
Box Test
Super Air Meter (SAM)Capillary Pressure SystemSurface Resistivity MIT SCAN T2
PropertyWorkabilityAir Void SystemPlastic Shrinkage Cracks
Permeability
Pavement thickness
New Tests and TechnologiesSlide13
Box Test
Developed by Dr. Tyler Ley, Oklahoma State University
Mixture response to vibrationConsolidation check Edge slump checkMix design tool
WorkabilitySlide14
A workability test
Simple (lends itself to QC)
Anticipated as a provisional test methodIncluded in PEM Specification
Box TestSlide15
4
3
2
1
Consolidation Issues
Edge Slump Issues
The Box Test Slide16
Finishability Issues
Project A
Project B
Edge slump Issues
The Box TestSlide17
Total air (4.0% - 8.0%)
Pressure air meter
Measure total air in the fieldBut, the air void system is what counts
Which
is freeze / thaw durable?
Air ContentSlide18
MCT
photo
AASHTO TP-08
Hover photo
ASTM C
457
Humboldt photo
ASTM C
666
AASHTO T 161
Spacing factor
Spacing factor
d
urability factor
Current Test MethodsSlide19
Measures the Air
Void System
Modification of existing air testMeasures air system qualitySmall bubbles implodeTest Test three times at different pressuresRepeat
Field friendly8-12 MinutesMeasures total air content
Super Air Meter (SAM)Slide20
Provisional Test Method
AASHTO TP 118
Resultant Pressure
14.5 psi
30 psi
45 psi
Pressure Introduced
SAM Number
2
nd
Pressure curve
1
st
Pressure curve
Time
Standard air pot total air value
SAM PrincipleSlide21
Small bubbles dissolve
Inverse of bubble coming out of soda after it is opened
Atmospheric
pressure
Pressure
step
6
SAM PrincipleSlide22
NOT GOOD
GOOD
Super Air Meter (SAM)
SAM ResultsSlide23
Ley
SAM vs. ASTM C457Slide24
Round Robin
Provisional Test Method – AASHTO TP 118
29 States, 2 Canadian provinces, and UK
SAM Current Status / ActivitiesSlide25
Rapid Chloride Penetrability Test (Indirectly)
Became standard in
1981Most common test Indicator of vulnerability to water and chloride ingressGenerally 24 hours to condition and 6 hours for testing
AASHTO T277/ASTM C1202
Permeability
(Surrogate Tests for Durability)Slide26
Sample Cutting
Epoxy Application
Desiccation
Cell Formation
Test
DAY 1
DAY 2
DAY 3
Rapid Chloride Permeability (RCP) TestSlide27
Surface
Resistivity Test (Indirectly)
StandardsAASHTO T 358-15
ASTM WK37880State specificationSeveral states
28-day age is being used
Instant results on hardened concrete
Easily measures the right propertyNon destructive test
Permeability
(Surrogate Tests for Durability)Slide28
RCP (Coulombs)
Surface Resistivity (
KOhm
-cm)
Surface Resistivity MeterSlide29
Significantly faster test
No sample preparation involved
Nondestructive No chemicals involvedLower equipment costLower labor costs
AASHTO T 358-15ASTM WK37880
Advantages of Resistivity TestingSlide30
Formation FactorSlide31
Probe (QC)
Coring (
QA)
Thickness Testing Slide32
Non-Destructive Technique for Measuring Concrete Pavement Thickness
Eliminates
coringSaves time, money, manpowerMany states are adopting
Step 1
Step 2
Step 3
Place the target
Pave
over it
Find the target
Measure the thicknessStep 4
MIT Scan T2Slide33
Easy to use
Non-destructive
Rapid measurementSignificant cost savingsHigh accuracy Within ± 0.1 inch of core thickness
FHWA Mobile Concrete Trailer
MIT Scan T2 - AdvantagesSlide34
Plastic Shrinkage
ACI
NomographSlide35
Capilla
ry
pre
ssure, concr
e
te
temperature
Enhan
ced c
apillary pressure s
ensor
Capillary Pressure Sensing SystemSlide36
C
on
c
r
ete
Capillary Pressure Sensing SystemSlide37
No Curing
With Curing
Influence of Curing on Capillary PressureSlide38
C
ap
illary pressure dependent
surface
re
wetting
-25
-20
-15
-10
-5
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5
0
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1
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Controlled Concrete CuringSlide39
Capillary Pressure Sensor System
CPSS Advantages / Uses
Takes concrete properties into account
Effectiveness of Curing Application rate
Evaluation of different Curing Compounds
Controlled Concrete CuringSlide40
HIPERPAV
Maturity
Coefficient of Thermal Expansion
UltraSonic
Pulse Echo
Microwave Water Content
Additional TechnologiesSlide41
MIT Scan 2
Calorimeter
Low Temperature DSR
V-Kelly
Additional TechnologiesSlide42
Tarantula CurveSlide43
Contact:
Office of Asset Management, Pavements, and Construction
HIPT-20, E73-105C
1200 New Jersey Avenue, S.E.
Washington D.C.
Phone: 202 366 1335
Mobile: 703 963 4939
jagan.m.gudimettla@dot.gov
https://www.fhwa.dot.gov/Pavement/concrete/mclfly.cfm