FHWA Mobile Concrete Lab Program Illinois Tollway Open House: Sustainable Concrete Paving Practices August 20, 2013
Mission Tech Transfer to SHA s Field demos on active projects Equipment loan Training of staff Conferences and workshops Focus currently on: Nondestructive/In-situ Tests Long Life Pavements MEPDG/AASHTO ME Design QA/QC
Technology Conventional QC Tests Nondestructive/In-situ Tests Durability Related Tests
Technology Conventional QC Tests Fresh Concrete Tests Strength (comp, flex, split) Elastic Modulus, Poisson Ratio NDT/In-situ Tests Durability Related Tests
Technology Conventional QC Tests Nondestructive/In-situ Tests Durability Related Tests
Nondestructive/In-situ Tests Pavement Thickness Dowel Bar Alignment Ultra Sonic Pulse Echo Maturity Match Cure Tensile Bond Strength
MIT SCAN T2 A faster, cheaper and non-destructive method to measure pavement thickness
MIT SCAN T2
Magnetic tomography technology MIT SCAN 2 Designed specifically for measuring dowel bar position and alignment
MIT SCAN 2 A method to evaluate dowel bar: Horizontal & vertical alignment Depth Side shift Spacing A means to predict joint performance
MIT SCAN 2 Problem Joints Typical Joint
Ultrasonic Pulse Echo - MIRA 1 pair per measurement 45 pair per measurement
MIRA Defect Detection Delamination Pavement-Base Interface poor consolidation/voids
MIRA Rebar Location D e p t h left bar middle bar right bar Pointing towards center of lane Pointing towards longitudinal joint
MIRA - Applications Applications Concrete cover depth Layer thickness Detection of delamination Internal defect detection Material properties PCC strength/stiffness HMA density
Maturity Method M = o Σ t (T-T o ) t Lab Field Temperature M Lab Temperature MField time time When M field = M lab, the strengths are the same
Maturity Method Laboratory Calibration Field Monitoring 3000 PSI Maturity (ASTM C 1074) When the maturity reaches this value, we can reliably say that the in-place strength is 3000 PSI
Maturity Meters
Match Cure Estimate In-place Strength of Concrete
Match Cure
Technology Conventional QC Tests Nondestructive/In-situ Tests Durability Related Tests
Durability Related Tests Rapid Chloride Permeability Test Surface Resistivity Meter Air Void Analyzer Coefficient of Thermal Expansion Calorimetry/Heat Signature HIPERPAV
Concrete Permeability Tests RCPT SR Meter Concrete ability to resist chloride ion penetration
Rapid Chloride Permeability (RCP) Test DAY 1 DAY 2 DAY 3 Sample Cutting Cell Formation Desiccation Epoxy Application Test
Surface Resistivity (SR) Meter
Surface Resistivity (SR) Meter RCP (Coulombs)
Freeze-Thaw Durability Entrained air (4.0% - 8.0%) Which situation is more desirable?
Freeze-Thaw Durability How do we characterize the air? ASTM C-457 Volume of Air Spacing Factor Specific Surface too late!
Air Void Analyzer (AVA) Measurement on FRESH concrete Sample at plant or on-site Takes about 20 minutes Allows for mixture adjustments
Air Void Analyzer (AVA)
Air Void Analyzer (AVA) Cement paste sample placed in a viscous liquid Air bubbles are released and rise to the surface Air Bubbles Large bubbles rise faster than small ones Cement Paste
Air Void Analyzer (AVA) Countertop unit Easy sampling On-site At plant 20-25 minute test Immediate results Allows for mixture adjustments
Air Void System Other Tests Freeze-Thaw Super Air Meter (SAM) ASTM C 457
Coefficient of Thermal Expansion (CTE) Why test CTE? Affects joint opening Affects sub-base restraint Affects curling Crack spacing and crack width (CRCP) CTE is primarily a function of: Aggregate type (carbonate, silicious) Reported in units of in/in/ F
Effect of CTE on Predicted Cracking
Coefficient of Thermal Expansion (CTE) CTE (Coefficient of Thermal Expansion, AASHTO T336) 50 C 10 C 0.0059
Coefficient of Thermal Expansion (CTE) CTE (Coefficient of Thermal Expansion, AASHTO T336) 50 C 10 C 0.0033
Coefficient of Thermal Expansion Submersible Non-Submersible
Heat Signature / Calorimetry Optimize Mixture materials and proportions Identify potential adverse interactions Troubleshoot field problems Screen and QC Raw Materials Reduce overtime to perform set times Compare Competitive Materials
Heat Signature / Calorimetry No Flyash??
What does HIPERPAV HIPERPAV do? Compares early-age pavement strengths and stresses to determine if cracking is likely Magnitude of Stress or Strength Strength Critical Stress Magnitude of Stress or Strength Cracking! Time since Construction Time since Construction Free download : www.hiperpav.com
Technology About sharing information Improve US infrastructure Improve quality Increase durability Minimize failure potential Lower overall cost
Customer Service Publish reports, journals, proceedings Conference/showcase presentations Provide speakers Specialized workshops Technical assistance
FHWA QA WORKSHOP Quality in the Concrete Paving Process
Sources of Variability Material Process Sampling Testing Composite Variability
Testing Monitor mixture quality during production and react to changes Gradation Slump Unit weight Air content Microwave water content Strength Permeability
Quality in the Concrete Paving Process Step 1 Field Step 2 Workshop Quality in the Concrete Paving Process Arizona 2013
Agenda Workshop Introduction Module 1: Quality Assurance Concepts Module 2: Materials and Characteristics for Quality Pavement Why Module 3: Pre-Paving and Mix Production Module 4: Paving Module 5: Utilizing Quality Concepts Module 6: Quality in Field Practice How What Both contractors and agency personnel!
Contacts Interested in our services? Contact either: FHWA Division Office FHWA Resource Center Mobile Concrete Laboratory Directly Gary Crawford (202) 366-1286 Jim Grove (515) 294-5988 Jagan Gudimettla (202) 366-1335
Gary Crawford Federal Highway Administration gary.crawford@dot.gov (202) 366-1286 WWW.FHWA.DOT.GOV/PAVEMENT/