Stiffness-Based QC/QA Humboldt Mfg. Co. GeoGauge Compaction Evaluation Today Stiffness-Based QC/QA GeoGauge : Material Evaluation Today

Humboldt Mfg. Co. Norridge, Illinois U.S.A. Mr. Scott Fiedler Product Manager Humboldt Mfg. Co. Norridge, Illinois U.S.A. Manufacturer & Distributor since 1909 Testing Equipment For Road Building Materials: Asphalt Concrete Soil Laboratory Apparatus GeoGauge : Material Evaluation Today

In-place stiffness & modulus Humboldt Mfg. Co. In-place stiffness & modulus Young’s Modulus Elastic Modulus Resilient Modulus resistance to change in shape in direction of stress Layer Stiffness resistance to deflection GeoGauge : Material Evaluation Today

Why Stiffness Based Compaction? (Why Measure Stiffness?) Humboldt Mfg. Co. Why Stiffness Based Compaction? (Why Measure Stiffness?) Objective To Improve Load Bearing Capability Reduce Variability Enable Effective Load Transfer & Distribution, Pavement To Subgrade Material Moduli New Benefits Minimized Pavement (Surface) Damage Double Surface Life Stiffness Makes Engineering Sense GeoGauge : Material Evaluation Today

Improvements With Stiffness Measurements Humboldt Mfg. Co. Improvements With Stiffness Measurements Optimum Compaction Effort Reduce Over-Compaction Reduce Variations Reduce Maintenance & Repair Costs Longer Lasting Smooth Surface Verify Supporting Base Properties Increase Surface Performance and Life GeoGauge : Material Evaluation Today

Benefits Of Stiffness Based QC Compaction Humboldt Mfg. Co. Benefits Of Stiffness Based QC Compaction Minimized Pavement Surface Damage > 50% Increase In Roadway Life > 50% Decrease In Roadway Maintenance Cost Directly Links Construction With Design Design & Construction Parameters Are The Same Enables Performance Specifications And Contractor Warranties Enables Use Of Reasonable Design Margins No Over Specification No Over Construction GeoGauge : Material Evaluation Today

Humboldt Mfg. Co. Variability Control Of Compaction Process Enable Control Of Variability Increase Life & Load Capacity. GeoGauge : Material Evaluation Today

Stiffness Variability Is Important Humboldt Mfg. Co. Stiffness Variability Is Important “ By reducing the variability of layer stiffness to +/- 25% of the mean, the life of the pavement surface will double over current practice.” (FHWA) Easily Achieved ! GeoGauge : Material Evaluation Today

What GeoGauge Measures Humboldt Mfg. Co. What GeoGauge Measures In-Place (In-Situ), 230 to 310mm Layer From Surface During The Compaction Process For Effective QC/QA Effective Young’s Modulus (elastic,resilient) Influenced By Normal Construction Boundaries Influenced By Construction/Contractor Operation Modulus Of A Layered Composite Material Modulus Of A Composite Material Lower Than The Sum Of The Moduli Of The Constituent Materials Effective Stiffness Of Composite Or Layered Structure Influenced By Material Modulus, Layer Dimensions And Layer Boundaries 230 to 310 mm from surface GeoGauge : Material Evaluation Today

GeoGauge Vibrates Ground & Measures the Deflection Humboldt Mfg. Co. GeoGauge Vibrates Ground & Measures the Deflection Superior Steady-State Sinusoidal Loading Technology 7,400 cycles ! GeoGauge : Material Evaluation Today

Basic GeoGauge Specifications Humboldt Mfg. Co. Basic GeoGauge Specifications 280 x 270 mm, 10 kg Effective Young’s Modulus: 610 MPa Effective Layer Stiffness: 70 MN/m Depth: 230 to 310 mm From Surface Battery Power Measurement Duration: 75 Seconds No License Required GeoGauge : Material Evaluation Today

GeoGauge Schematic Humboldt Mfg. Co. GeoGauge : Material Evaluation Today

GeoGauge Features Does Not Interfere Or Delay Construction Humboldt Mfg. Co. GeoGauge Features Does Not Interfere Or Delay Construction Detects Small Differences Self-Contained & Hand-Portable Quick Not Affected By Construction Vibration, Wind or Slope Robust, Reliable, Low Cost & Easy To Use Established Bias, < 1% COV Established Precision, Typically < 7% COV Meets ASTM D6758 GeoGauge : Material Evaluation Today

GeoGauge Procedure Is Simple Humboldt Mfg. Co. GeoGauge Procedure Is Simple Inspect GeoGauge & Power On Select Mode & Poisson’s Ratio Prepare & Smooth Ground Seat Foot Place & 1/2 turn on soft materials Place & 1/4 turn with wet sand over hard materials or rough surfaces Take Measurement: 75 sec. Record Data GeoGauge : Material Evaluation Today

Simple, Quick & Safe ! Remove Lose Material Smooth Surface Humboldt Mfg. Co. Simple, Quick & Safe ! Remove Lose Material Smooth Surface Moist Sand Fill Voids Pat Firmly Sand Pad Place GeoGauge Press Measure Button Result In 75 Seconds GeoGauge : Material Evaluation Today

Seating On Hard or Rough Surfaces Humboldt Mfg. Co. Seating On Hard or Rough Surfaces Use Wet Sand To Ensure Maximum Contact GeoGauge : Material Evaluation Today

GeoGauge Applications Humboldt Mfg. Co. GeoGauge Applications Compaction QC/QA Unbound & Bound Materials Soil, Soil-Aggregates & Aggregates Cement Treated Materials Minimize Asphalt Surface Reflective Cracks Subgrade & Base Stabilization Ensure Required Strength & Minimize Construction Down Time Trench / Utility Cut Backfill Ensure Duplication Of Original Properties Hot & Cold Mix Asphalt QC/QA Compaction & Strength Evaluation Forensic Investigations GeoGauge : Material Evaluation Today

Stiffness-Based Specifications Humboldt Mfg. Co. Stiffness-Based Specifications FHWA / 25 State DOTs Development Of AASHTO Standard Specifications Underway For 2006 Construction Season GeoGauge : Material Evaluation Today

Specified For QC/QA of Roadway Layers & Cement-Treated Bases Humboldt Mfg. Co. Specified For QC/QA of Roadway Layers & Cement-Treated Bases GeoGauge : Material Evaluation Today

Specified To Implement Mechanistic-Empirical Design Humboldt Mfg. Co. Measure Material’s In-Place Modulus Level 1 Input (AASHTO 2002 Guidelines) GeoGauge : Material Evaluation Today

QC/QA of Granular Materials Humboldt Mfg. Co. QC/QA of Granular Materials Measurements Yield Dry Density GeoGauge : Material Evaluation Today

Density Relationship Humboldt Mfg. Co. GeoGauge : Material Evaluation Today

Density Relationship Humboldt Mfg. Co. GeoGauge : Material Evaluation Today

Possible QC/QA Criteria! Humboldt Mfg. Co. Possible QC/QA Criteria! 400 Field Tests Lab Tests 300 Log(E-Ge) = 0.54 * log(E-PLT) + 2.22 R 2 = 0.725 GeoGauge (MPa) 200 100 100 200 300 400 500 Plate Load Test (MPa) GeoGauge : Material Evaluation Today

Humboldt Mfg. Co. Geogauge - FWD FWD = 1.355 Geogauge – 39.8 R2 = 0.81 at 95% level confidence N=29 FWD (MPa) GeoGauge (MPa) GeoGauge : Material Evaluation Today

Correlation to Other Moduli Humboldt Mfg. Co. Correlation to Other Moduli 300 600 900 1200 1500 50 100 150 200 250 350 400 500 1000 2000 2500 -50 1 2 3 4 5 6 95 105 110 115 120 PFWD (small plate) PFWD (large plate) DCP (6" avg.) DCP (3" avg.) GeoGauge sc compaction ng compaction Section 17, Mn/ROAD 13 Pavement Sections at 5 MnDOT Sites Modulus (MPa) Compaction (%) Subgrade & Base Materials In 6 TXDOT Districts GeoGauge, E G , (MPa) E F = 4.08E - 231.53 Correlation Coefficient: .80 FWD vs. GeoGauge Modulus FWD, E Seismic vs. GeoGauge Modulus S = 6.27E - 31.91 Correlation Coefficient: .79 Seismic, E GeoGauge : Material Evaluation Today

GeoGauge Operation Principle Humboldt Mfg. Co. GeoGauge Operation Principle Cyclic Vertical Loading 7400 X 25 Discrete Frequencies 100 To 196 Hz, 4 Hz Increment, 2 Seconds Each Each Frequency = 1 Test, Result is Average of 25 Self-Filtering Ground Anomaly / Infinitely Variable 2 Geophone Sensors & 1 Driver 1 Force 1 Displacement GeoGauge : Material Evaluation Today

Operation Principles cont. Humboldt Mfg. Co. Operation Principles cont. Stiffness = Force over Displacement. At Low Frequencies, ground-input impedance is dominantly stiffness controlled. GeoGauge : Material Evaluation Today

Operation Principles cont. Humboldt Mfg. Co. Operation Principles cont. Internal Flexible Plate is Reference Stiffness. GeoGauge : Material Evaluation Today

Operation Principles cont. Humboldt Mfg. Co. Operation Principles cont. Relationship Of Stiffness To Young’s & Shear Modulus . (Poulos & Davis) GeoGauge : Material Evaluation Today

Operation Principles cont. Humboldt Mfg. Co. Operation Principles cont. Averaging Over Operating Frequencies & Substituting Velocity, V, for Displacement, X, Ground Stiffness Is As Follows. Avoids the need for non-moving reference for displacement & permits accurate measurement of small displacements GeoGauge : Material Evaluation Today

Calibration Principles Humboldt Mfg. Co. Calibration Principles GeoGauge : Material Evaluation Today

Review Stiffness Based Compaction QC/QA Makes Sense Humboldt Mfg. Co. Review Stiffness Based Compaction QC/QA Makes Sense Minimized Pavement Damage Directly Links Construction With Design Enables Use Of Reasonable Design Margins GeoGauge Measures Stiffness In-Place Layer Stiffness & Modulus Of Composite Materials GeoGauge Is Practical For QC/QA Small, Light, Quick, Simple & Non-Invasive Many Applications Roadway & General Compaction Subgrade, Base & Pavement Soil, Aggregate & Asphalt GeoGauge : Material Evaluation Today

Verifier Mass Ensures Operation Humboldt Mfg. Co. Verifier Mass Ensures Operation Measures ‘stiffness’ value of compliant-mounted mass. (10.0 kg) Average of 3 to 5 measurements, remove & rotate 45 to 90 degrees between measurements. Should be -9.3 +/- 5%. (Between -8.8 & -9.8) Negative sign represents mass. GeoGauge : Material Evaluation Today

Verify Operation Daily Humboldt Mfg. Co. Verify Operation Daily To be made at the beginning of every test day. Ensures operation is correct. Deviations can be easily corrected by calibration on same Verifier Mass. GeoGauge : Material Evaluation Today

GeoGauge™ Use & Seating Procedure Humboldt Mfg. Co. GeoGauge™ Use & Seating Procedure Seating & Measurement Procedures For Proper GeoGauge Measurements GeoGauge : Material Evaluation Today

GeoGauge Seating Procedure Humboldt Mfg. Co. GeoGauge Seating Procedure Established Jointly with State DOTs, FHWA & Humboldt Procedure Standardized ASTM D6758 Operator Bias Minimized or Eliminated GeoGauge : Material Evaluation Today

Firmly Hand-Pack Wet Sand Humboldt Mfg. Co. Firmly Hand-Pack Wet Sand One small handful Fills cavities Hand-packing does not change material properties Make Sand Pad approximately 150mm dia. x 3 to 6mm thick Placing and quarter-twist of GeoGauge further reduces amount of sand between ring foot and material surface GeoGauge : Material Evaluation Today

Practice, Practice, Practice Humboldt Mfg. Co. Practice, Practice, Practice A must for new technicians or users Becomes proficient & confident Ensures reliable measurements on projects Practice on ‘real’ compacted surfaces Recommended for experienced users Profiles & Identifies Deviations Faster Quickly addresses problems while equipment still on-site Primary QC benefit GeoGauge : Material Evaluation Today

Confirm Measurement Precision Humboldt Mfg. Co. Confirm Measurement Precision Minimum of three (3) measurements on representative site and material. At the beginning of each test day and each site. Confirm precision. About 8% COV or less is good. Practice & experience improves COV. GeoGauge : Material Evaluation Today

Suggested Supplies Brush to remove loose materials Gloves & knee-pads Humboldt Mfg. Co. Suggested Supplies Brush to remove loose materials Gloves & knee-pads Helps to prepare surfaces more quickly All supplied by technician or user. Not shown: paper & pen to document measurement data, material type & water content, layer thickness and other conditions for database purposes. GeoGauge : Material Evaluation Today

Humboldt Mfg. Co. Prepare Surface Use a solid scraper to remove any loose, dry, hard top materials and to make surface flat. Use brush to help remove readily loose materials. Surface must be moist and free of loose materials before wet sand is applied. Any user supplied flat scraper or stiff brush can be used. GeoGauge : Material Evaluation Today

Brush Away Loose Material Humboldt Mfg. Co. Brush Away Loose Material Can be used instead of scraper plate. Use brush to quickly remove loose material. Do not ‘pick’ or remove protruding attached stones or disturb material. GeoGauge : Material Evaluation Today

Humboldt Mfg. Co. Container of Wet Sand Use fine, well-graded & clean manufactured sand that has good adhesion when wet. Often called masonry or mortar sand. 10 to 15% moisture is ideal. GeoGauge : Material Evaluation Today

Humboldt Mfg. Co. Place Wet Sand A small handful is generally all that is required for freshly compacted material. Drop onto the surface. Sand may not be required if ring-foot pattern is clearly visible without sand, which indicates soil is soft enough to conform to ring-foot for complete contact. GeoGauge : Material Evaluation Today

Small Handful of Wet Sand Humboldt Mfg. Co. Small Handful of Wet Sand GeoGauge : Material Evaluation Today

Firmly Hand-Pack Wet Sand Humboldt Mfg. Co. Firmly Hand-Pack Wet Sand Spread the sand to a pad shape about 150mm dia. & no more than 6mm thick. Use more sand for a thicker pad when required where surface is rough. Pack firmly, equal & smooth. GeoGauge : Material Evaluation Today

Always Use Wet Sand Ensures Full & Equal Annular Contact Humboldt Mfg. Co. Always Use Wet Sand Ensures Full & Equal Annular Contact Repeatability Thin layer of sand has no influence Well-Graded, Fine Mortar or Masonry Sand Provides good adhesion 10 to 20% moisture Sand may not be required if, without sand, a complete 360 degree ring-foot pattern is clearly visible, which indicates soil is soft enough to conform to ring-foot for complete contact. GeoGauge : Material Evaluation Today

Place GeoGauge Rest GeoGauge ring-foot on center of sand pad. Humboldt Mfg. Co. Place GeoGauge Rest GeoGauge ring-foot on center of sand pad. No addition downward force. GeoGauge : Material Evaluation Today

Twist One/Quarter Turn Humboldt Mfg. Co. Twist One/Quarter Turn With both hands on side of GeoGauge, apply a one-quarter turn or twist only, to complete the seating. Do not apply additional downward force. Most critical step in seating the GeoGauge. GeoGauge : Material Evaluation Today

Humboldt Mfg. Co. Press ‘MEAS’ Button Gently Press the ‘MEAS’ button, without shaking the GeoGauge Take one-step back to avoid influence of body-weight Measures the surface noise before actual stiffness measurements. GeoGauge : Material Evaluation Today

Humboldt Mfg. Co. Results in 75 Seconds Displays the lowest signal-to-noise ratio of the 25 discrete frequency. Displays the standard deviation of the 25 discrete frequency. Finally displays the stiffness or modulus values. Record data. GeoGauge : Material Evaluation Today

Acceptable ‘Foot-print’ Humboldt Mfg. Co. Acceptable ‘Foot-print’ Good, equal annular print is acceptable. Try to twist one-quarter turn on its axis as good as practical. Acceptable foot-print pattern can only be determine after measurement Practice will improve acceptance GeoGauge : Material Evaluation Today

Humboldt Mfg. Co. Questions ? GeoGauge : Material Evaluation Today