Post on 27-Jul-2018
Assessment of Non-Destructive Testing Technologies for QC/QA of Asphalt Mixtures
TR-653
PI: Jeramy Ashlock (ISU)PhD Research Assistant: Shibin Lin
Co-PIs: R. Christopher Williams (ISU), Hosin (David) Lee (UI)TAC: Scott Schram, Jeff Schmitt, Jason Omundson
Department of Civil, Construction, and Environmental Engineering
IOWA STATE UNIVERSITY
Project Goals
1. Assess accuracy, suitability of several NDE technologies for QC/QA of asphalt pavement
2. Perform preliminary study on QC/QA and subsequent health monitoring of asphalt pavements using embedded MEMS sensors
2/32
OutlineI. Equipment and Methods
1) PaveTracker: Dielectric constant → Density2) GeoGauge: Mechanical impedance, force/deflection → Stiffness3) Surface wave test: Seismic wave speed → G=ρVs
2 , E=2(1+ν)GDispersion properties → Layer thickness & modulus
(if inversion analysis performed)
4) MEMS Sensor → moisture & temperatureII. Paving project test locationsIII. Results
1) Field: density, stiffness, wave speed (modulus)2) Lab: density, dynamic modulus3) Correlations
IV. Conclusions3/32
GeoGauge(Humboldt)
Equipment
PaveTracker(Troxler)
Custom-built surface wave testing equipment (Lin & Ashlock)
MASW
MSOR
4/32
Surface Wave Test Methods
Multichannel Analysis of Surface Waves (MASW)
Multichannel Simulation with One Receiver(MSOR)
5/32
Data acquisition and analysis system programmed in MATLAB
SWM Data Acquisition/Analysis Program
6/32
MEMS Sensor
MEMS-based, RFID wireless, passive (battery-less), moisture & temperature sensor from Phase IV Engineering.
Installed on one paving project to test survivability & readability through asphalt for QC/QA and long-term performance monitoring.
Currently working with Phase IV on wireless MEMS strain sensors for concrete, asphalt.
Photo: Simon LaFlamme, ISU
http://www.phaseivengr.com/
7/32
Field Tests: Pavetracker, Geogauge, SWM, Cores
MSOR
8/32
Lab Tests: Density by SSD and Corelok
MSOR
9/32
Lab Tests: Dynamic Modulus by IDT
MSOR
10/32
Paving project test locations
1. Boone: Central Iowa Expo project (HMA and WMA)
2. Story/Hamilton: US 69 S. of Co. Rd. E-18 to S. jct. IA 175 (HMA)
3. Fayette: IA 93 from Sumner to IA 150 (FDR, CIP, OL)
4. Dallas: US 169 fr. Raccoon Mill Race to N. Raccoon River (HMA)
5. Johnson: US 6 fr. S. jct. IA 1 to Lakeside Dr. (HMA, WMA w/RAP)
6. Stanhope: IA 17 (MEMS sensor)
11/32
Field Tests and Cores
Project Location # Tests
Boone Central Iowa Expo (HMA, WMA)
Base 35
Surface 16
US 69 (HMA) Surface 9
I 93 (FDR, CIP, OL) Surface 2, 2, 2
US 169 (HMA) Surface 6
US 6 (HMA, WMA w/RAP) Surface 6, 4
Total: 82
SWM
PaveTracker GeoGauge
Core
12/32
Results: SWM wave speedSWM testing of base Core HB1-1 in Boone
HOT COLD (ambient)
•Rayleigh wave velocities increase significantly as asphalt pavement cools 13/32
Results: Average in situ modulus E
0.0E+00
5.0E+03
1.0E+04
1.5E+04
2.0E+04
Aver
age
E (M
Pa)
•Modulus decreases as traffic volume decreases. 14/32
Results: Indirect tension (IDT) modulus E (Master curve)
15/32
Correction of Field Modulus to Reference Temperature
16/32
Correction of Field Modulus to Reference Temperature
17/32
Results: Corrected IDT modulus
•Modulus decreases as traffic volume decreases.•HMA has slightly higher modulus than WMA.•After correcting field moduli to common reference temperature: excellent agreement with rank of master curves 18/32
Results: GeoGauge stiffness
•Stiffness increases as temperature decreases.
19/32
Results: GeoGauge stiffness
0
10
20
30
40
50
60
70
80
US 6-HMA US 6-WMA IA 93-OL US 69-HMA Boone-HMAsurface
Boone-WMAsurface
IA 93-CIP IA 93-FDR
Stiff
ness
(MN
/m)
0102030405060708090
100
Stiff
ness
(MN
/m)
HOT
COLD &AMBIENT
•GeoGauge HOT stiffness is more consistent with traffic volume. 20/32
Results: PaveTracker density19 HMA and 16 WMA base cores (4”) from Boone
•Hot = 1 to 3 hours after paving, Cold = next day (same locations)•Increase in scatter and slight decrease in avg. density overnight 21/32
Results: Correlation of PT and CoreLok densities
•Low correlation between field PT and lab Corelok density22/32
Results: Comparison of PT and CoreLok average densities
1800
2000
2200
2400
2600
2800Av
erag
e ho
t den
sity
(kg/
m3)
180020002200240026002800
Aver
age
dens
ity (k
g/m
3)PT
CoreLok
23/32
Results: Correlation of Vs and PT/CL densities
•SWM velocity correlates poorly with PT density, well with CoreLok density24/32
In situ modulus from SWM Vs and PT density
•PT density is adequate for using with SWM Vs for NDE of in situ modulus 25/32
Results: Correlation of SWM modulus and GG stiffness
•SWM modulus correlates reasonably with HOT GeoGaugestiffness, but not with cold GG stiffness 26/32
Results: Correlation of GG stiffness and PT/CL densities
•Hot GG stiffness better than cold, but poor correlations
27/32
Quick NDT Quality Control Procedure
28/32
NDT Quality Assurance Procedure
29/32
Mod
ulus
Frequency
T1
T2
T3
TF
In-situmodulusCorrectedmodulus
In-situ modulus ETF
Corrected modulus
Reduced frequency, fr
Emax
Proposed QA rating system
30/32
Proposed quality ratings based on SWM modulus ratios.
EC21/Emax (%) >80% 60−80% 40−60% 20−40% <20% Quality rating Very high High Moderate Low Very low
QC/QA assessment for six pavement test sections in this study.
Project/ Pavement
Type
QC QA EC21QC
(MPa) EC21QC / Emax
(%) Quality rating EC21QA
(MPa) EC21QA / Emax
(%) Quality rating
US 6 HMA 20,684 94.5% Very high 19,546 89.3% Very high US 6 WMA 19,079 99.6% Very high 18,585 97.0% Very high Boone HMA 13,164 49.3% Moderate 15,021 56.2% Moderate Boone WMA 14,641 74.9% High 14,015 71.7% High
US 69 6,278 34.9% Low 6,272 34.9% Low IA 93 OL 6,210 30.2% Low 6,079 29.6% Low
Preliminary Study on Embedded MEMS-based Sensors for QC/QA
•One sensor configuration survived paving and was successfully read through 2” of ACC•Wireless, battery-less, RFID•Currently working with Phase IV on strain gauges
31/32
Conclusions and Recommendations1. PT density had low correlation with laboratory density.2. In situ density not very sensitive to temperature variation, whereas SWM shear-
wave velocity is very sensitive to temperature.3. GeoGauge stiffness measured on hot asphalt mixtures several hours after
paving has good correlation with in situ dynamic modulus and laboratory density, is recommended for QC.
4. Accurate and objective QC/QA procedure developed, based on dynamic modulus from measured shear-wave velocity and density by efficient and economical NDT methods (SWM and electromagnetic density gauges).
5. For implementation of the QA procedure: recommended to develop master-curve database of as-built pavements using IDT dynamic modulus tests.
6. Periodic SWM+PT and/or GG tests recommended for health monitoring (compare to benchmark tests on given pavement).
7. Further development of strain gauges in collaboration with Phase IV Engineering is recommended for MEMS-based QA and health monitoring.
32/32
Questions and comments?
33/32
What do surface waves look like?
(from Braile, 2004)
34/32
Surface wave tests on pavements vs. soils• Make use of dispersive nature of Rayleigh waves, by
which different frequency components of a disturbance travel at different phase velocities
Lower frequencies involve motion at greater depths, so they measure velocity & modulus of deeper layers.
Phas
e Ve
loci
ty
Frequency
Dispersion curve Layer thickness and stiffness
1. Soil stiffness (modulus) generally increases with depth, so velocity increases as frequency decreases: “Normally dispersive”
2. Pavement stiffness decreases with depth, so velocity increases as frequency increases: “Inversely dispersive”
Soil
Pavement
35/32
4. Profiles after inversion3. Inversion: mimizingmisfit between theoretical & experimental curves by optimization methods
2. Modeling: calculate theoretical dispersion curves for assumed soil profiles
1. Testing
Frequency
Phas
e Ve
loci
ty
Experimentaldispersion curve
Frequency
Phas
e Ve
loci
ty
h1, VS1
h2, VS2
h3, VS3
Tim
e
Receiver
Frequency
Phas
e Ve
loci
ty
Theoreticaldispersion curve (Matrix methods)
h1, VS1
:hn, VSn
Surface wave testing & analysis procedure
36/32