The FHWA Mobile Concrete Trailer ( MCT)Bringing New Technologies toYour DoorstepJagan Gudimettla, P.E.ATI Inc (Consultant to FHWA)1

Program Goals Implement new and proven concretetechnologies Evaluate new tests and equipment Demonstrate the benefits of statistical materialsacceptance in both agency acceptance programsand industry quality control applications Assist states with concrete issues– Specification review and development– Technical assistance– Forensics

FHWA Mobile Concrete Trailer (MCT) Nondestructive/In-situTests PerformanceRelatedSpecifications SustainabilityMCT FocusAreas AASHTOWarePavement ME Design Performance QualityAssuranceEngineered Mixtures

MCT Activities Field visits to active construction projects Quality in the Concrete Paving ProcessWorkshop Assist with (PEM) implementation Equipment Loan Program, One-on-one Training Conferences, papers, and other activities

MCT Field Visits Activefield project for a two week period Traditional and Innovative testing Data in control chart formatKick-Off MeetingTestingWeek 1Testing

MCT Field Visits Activefield project for a two week period Traditional and Innovative testing Data in control chart formatTestingTestingWeek 2Open House

MCT Field Visits Closeout meeting with the state DOT, FHWAdivision office and contractor Summary report A free QA workshop using the field visit dataClose OutQA Workshop

Quality in the Concrete PavingProcess (QA Workshop) Two-day workshop on the benefits a QualityAssurance Program Increase concrete pavements life at reduced cost Contactor benefits of improved Quality Control New technologies and tools for testing and inspection Agency and Contractor Participation Class size 30 to encourage discussionDOT (QA/QC, Materials, Construction Staff etc.)Contractor staff (Superintends, QC Managers etc.)FHWA Division Office Staff

PEM Implementation Assisting PEM Team and TFHRC with ongoingPEM-related research Continuing to assist with Super Air Meter Parallel PEM and state testing during fieldvisits Demonstrating PEM equipment and testing Conferences and other venues Investment through Equipment LoanProgram

Equipment Loan Program States or industry can borrow MCTequipment MCT staff will provide training, if desired PEM focus Anticipate substantial new equipmentpurchase for Spring 2018 Currently enhancing information on ourwebsite

Training Oneon one training to DOT engineers and technicians Side by side comparison of new technologies

Other Activities Conferences (5-6 a year) NationalConferences (ACI, TRB, ISCP, etc) State DOT / Industry conferences Provide speakers Specialized Workshops Technical Assistance Papers Practical papers based on datacollected at field projects

One Pagers New effort to use MCT data Narrowly focused Meant to stir interest andpoint reader to resources– 1st : Cement Content– 2nd: Optimized Mix Design– 3rd : Cores vs. Cylinders

MCT StaffMike PraulNicolai MorariJagan GudimettlaJim GroveJerry Clemons

New Tests Box Test Workability Super Air Meter Freeze-Thaw Durability MIT Scan T2 Pavement Thickness

The Box Test A simple test that examines: Response to vibration Filling ability of the grout (avoid internal voids) Ability of the slip formed concrete to hold a sharpedge

The Box Test434Over 50% overall surface voids.Over 50% overall surface voids.330-50% overall surface voids.30-50% overall surface voids.44 43 evoids.22210-30% overall surface voids.10-30% overall2 allsurfacevoids.311 1Less than 10% overall surface voids.Less than 10% overall1 1 surface erallsurfacevoids.Consolidation IssuesEdge Slump Issues

The Box Test

Air Content Total air (4.0% - 8.0%) Pressure air meter Measure total air in the field But, the air void system is what countsWhich is freeze / thaw durable?

Current Test MethodsHover photoHumboldt photoMCT photoASTM C 457ASTM C 666AASHTO T 161AASHTO TP-08durability factorSpacing factorSpacing factor

Super Air Meter (SAM) Measures the Air Void SystemModification of existing air test Measures air system quality Small bubbles implode Test Test three times at different pressures Repeat Field friendly 8-12 Minutes Measures total air content

SAM Principle Provisional Test Method– AASHTO TP 118Resultant Pressure2nd Pressure curve30 psi14.5 psi45 psiSAMNumber1st Pressure curveStandard air pot total air valueTimePressure Introduced

SAM PrincipleSAM Number0.8SAM NumberSAM Criteria0.6NOT GOOD0.40.2GOOD02-2Super Air Meter(SAM)2-32-43-2Sample ID3-3

SAM vs. ASTM C457Ley

Pavement Thickness Pavement life is influenced by thickness Important QA activity Probing (QC)/ Coring (QA)

MIT Scan T2A faster, cheaper andnon-destructive methodto measure pavementthickness

MIT Scan T2

MIT Scan T2 Advantages Easy to useNon-destructiveRapid measurementIndependent of the base materialIndependent of the maturity of concreteSignificant cost savings compared to taking coresHigh accuracy (within 0.1 inch of core thickness)

Many Other TechnologiesHIPERPAVSurface ResistivityTest (Indirectly)MIT Scan 2Capillary SensorsCome see us in theGammage Parking Lot

Benefit - Equipment Loan ProgramExample- Iowa Specification (thickness) MIT Scan T2 (non-destructive pavement thickness) Introduced the technology to Iowa DOT (2008)Equipment loan to Iowa DOT (2008)Iowa DOT evaluated the technology- two projects (2009)Trial Specification – four projects (2010)Full Specification (2011)Iowa DOT purchased devices for each of their 6 districtsAASHTO Test Method Iowa DOT and MCT Joint Effort (2014-2016)

Benefit- Technical AssistanceExample- West Virginia Specification (Strength) West Virginia specifications (through 2016) requiredcores to be taken for acceptance MCT made a field visit to WV in Fall 2015– Cast cylinders from actual paving project– Compressive strength testing performed at various ages QA workshop in 2016– In-depth discussion on the compressive strength data– Emphasized the advantages of using cylinders versus cores foracceptance West Virginia DOT revised 2017 specifications to usecylinders for strength acceptance.

Technical Assistance Review of Specifications––––––––Pennsylvania Division Office/PennDOTOklahoma Division Office/OKDOTNew Mexico DOTMontana DOTNYSDOTNorth Dakota DOTSouth Dakota Division Office/SD DOTVirginia DOT Forensic Investigations– Premature Pavement Cracking in North Dakota– Premature median barrier failure in Idaho

Impact – Some Recent ExamplesSpecification changes Nondestructive Pavement Thickness–––––––––––Iowa DOTWest Virginia DOTPenn DOTNorth Dakota DOTIllinois TollwayWisconsin DOTOhio DOT (considering change)Washington DOT (considering change)Delaware DOT (considering change)Nevada (considering change)Alabama (considering change) Acceptance Testing(cores to cylinders) Alabama DOT West Virginia DOT Box Test (consideringchanges) Idaho DOT Ohio DOT

Impact – Some Recent ExamplesSpecification changes Optimized AggregateGradation–––––Ohio DOTWest Virginia DOTIdaho DOTMaine DOTMassachusetts DOT Nondestructive Dowel Bar Alignment–––––––CaltransIdaho DOTIL TollwayNorth CarolinaOhio DOTNew York State ThruwayNevada

Contact:Office of Preconstruction, Construction, and PavementsHIPT-20, E73-105C1200 New Jersey Avenue, S.E.Washington D.C.Phone: 202 366 1335Mobile: 703 963

Directions to the MobileConcrete Trailer

Demonstrating PEM equipment and testing Conferences and other venues Investment through Equipment Loan Program PEM Implementation States or industry can borrow MCT . Humboldt photo ASTM C 666 AASHTO T 161 Spacing factor Spacing factor durability factor Current Test Methods Measures the Air Void System