The National Academies Press

Currently Skimming:

Pages 1-22

The Chapter Skim interface presents what we've algorithmically identified as the most significant single chunk of text within every page in the chapter.
Select key terms on the right to highlight them within pages of the chapter.

From page 1... ... Objectives The overall objective of NCHRP Project 10-65 was to identify NDT technologies that have immediate application for routine, practical QA operations to assist agency and contractor personnel in judging the quality of hot mix asphalt (HMA) overlays and flexible pavement construction. Read the entire page →
From page 2... ... NDT Devices Included in the Field Evaluation A large number of NDT technologies and devices have been used for pavement evaluation and forensic studies. Table 2 summarizes the technologies and methods that have been used to measure different properties and features of flexible pavements. Read the entire page →
From page 3... ... master curve. Field Verification of Mixture Design Select/Establish QA criteria for measuring quality; determine seismic design modulus. Read the entire page →
From page 4... ... Property Needed for: Pavement Layer Material-Layer Property Structural Design Mixture Design Acceptance Density – Air Voids at Construction Yes Yes Voids in Mineral Aggregate Yes Yes Effective Asphalt Binder Content Yes Yes Voids Filled with Asphalt Yes Gradation Yes Yes Asphalt Binder Properties Yes Yes IDT Strength and Creep Compliance Yes Yes Dynamic Modulus Yes Yes Flow Time or Flow Number Yes HMA Layers; Dense-Graded Mixtures Smoothness, Initial Yes Density Yes Yes Water Content Yes Yes Gradation Yes Yes Minus 200 Material Yes Yes Plasticity Index (Atterberg Limits) Yes Yes Resilient Modulus Yes Yes CBR or R-Value Yes Yes Unbound Layers; Dense Graded Granular Base, Embankment Soils Strength DCP; Penetration Rate Yes IDT – Indirect Tensile CBR – California Bearing Ratio DCP – Dynamic Cone Penetrometer Table 1. Read the entire page →
From page 5... ... • Relationship between the test result and other traditional and advanced tests used in mixture design and structural design. NDT Technologies and Methods Type of Property or Feature HMA Layers Unbound Aggregate Base and Soil Layers Density GPR Non-Nuclear Gauges; PQI, PaveTracker GPR Non-Nuclear Gauges; EDG, Purdue TDR Air Voids or Percent Compaction GPR Infrared Tomography Acoustic Emissions Roller-Mounted Density Devices GPR Roller-Mounted Density Devices Fluids Content GPR GPR Non-Nuclear Gauges; EDG, Purdue TDR Gradation; Segregation GPR Infrared Tomography ROSAN NA Volumetric Voids in Mineral Aggregate GPR (Proprietary Method) Read the entire page →
From page 6... ... Thus, non-nuclear density gauges that provide location-specific results were selected for evaluation under this study. The gauges selected for initial use were the PQI and PaveTracker for HMA mixtures, while the EDG was selected for unbound materials. Read the entire page →
From page 7... ... A secondary purpose of this part of the field evaluation was to confirm that the NDT device can be readily and effectively implemented into routine QA programs for flexible pavement construction and HMA overlays -- an impact assessment. Part B of the field evaluation was to use those NDT technologies and devices selected from Part A and refine the test protocols and data interpretation procedures for judging the quality of flexible pavement construction. Read the entire page →
From page 8... ... Part Project Identification & Location Layer/Material Evaluated HMA Dense-Graded Base Mixture Granular Base Class 6, Crushed Aggregate A 1 TH-23 Reconstruction Project; Wilmar/Spicer Minnesota Class 5 Embankment Low Plasticity, Improved Soil with Gravel & Large Aggregate Particles A 2 I-85 Overlay Project; Auburn, Alabama HMA 12.5 mm Stone Matrix Asphalt Mix; PG7622 HMA Coarse-Graded Base Mixture; PG67-22 Granular Base Crushed Limestone Base A 3 US-280 Reconstruction Project; Opelika, Alabama Embankment Improved Soil; Aggregate-Soil Mix A 4 I-85 Ramp Construction Project; Auburn, Alabama Embankment Low Plasticity, Fine-Grained Soil HMA Coarse-Graded 19 mm Base Mixture; PG64-22A 5 SH-130 New Construction Project; Georgetown, Texas Embankment Coarse-Grained Aggregate/Soil; Improved Soil A 6 SH-21 Widening Project; Caldwell, Texas Subgrade High Plasticity Fine-Grained Soil with Gravel HMA Coarse-Graded Base Mixture B 7 US-47 Widening Project; St. Clair, Missouri HMA Fine-Graded Wearing Surface B 8 I-75 Rehabilitation Project, Rubblization; Saginaw, Michigan HMA Dense-Graded Binder Mixture; Type 3C HMA Coarse-Graded Base Mix; PG58-28 Granular Base Crushed Gravel with Surface Treatment; Class 5 B 9 US-2 New Construction; North Dakota Embankment Soil-Aggregate Mixture HMA Coarse-Graded Binder Mixture B 10 US-53 New Construction; Toledo, Ohio Granular Base Crushed Aggregate; Type 304 B 11 I-20 Overlay; Odessa, Texas HMA Coarse-Graded Mixture; CMHB B 12 County Road 103; Pecos, Texas Granular Base Caliche, Aggregate Base NCAT; Alabama Overlay, Section E-5, Opelika, Alabama HMA Wearing Surface with 45% RAP; PG67, no modifiers used. Read the entire page →
From page 9... ... None of the NDT devices accurately predicted the modulus values that were measured in the laboratory for the unbound materials and HMA mixtures. However, all of the modulus estimating NDT devices did show a trend of increasing moduli with increasing laboratory measured moduli. Read the entire page →
From page 10... ... Physical differences in the unbound materials and soils placed along some of the projects. Project Identification HMA Sections Description of Differences Along the Project TH-23 HMA Base; Spicer, Minnesota Section 2, Middle or Northeast Section QA records indicate lower asphalt content in this area -- asphalt content was still within the specifications, but consistently below target value. Read the entire page →
From page 11... ... 103, TX Caliche Base -- - 32.3 1.214 -- - 1.436 -- - NCAT, SC Crushed Granite 14.3 36.1 0.947 0.156 -- - -- - NCAT, MO Crushed Limestone 19.2 40.9 0.747 0.198 -- - -- - Crushed Stone, Middle 24.0 29.9 0.851 0.303 0.725 1.69 TH-23, MN Crushed Stone, South 26.0 35.6 0.788 0.235 0.560 1.69 US-53, OH Crushed Stone 27.5 38.3 1.170 0.449 0.862 -- - NCAT, FL Limerock 28.6 28.1 0.574 0.324 0.619 -- - US-2, ND Crushed Aggregate 32.4 39.8 1.884 0.623 1.129 -- - US-280, AL Crushed Stone 48.4 49.3 1.010 0.244 0.962 1.04 Average Ratios for Aggregate Base Materials 1.021 0.316 0.899 Overall Average Ratios for Processed Materials 0.942 0.422 1.084 NOTES: 1. The adjustment ratio is determined by dividing the resilient modulus measured in the laboratory at a specific stress state by the NDT estimated modulus. Read the entire page →
From page 12... ... and Ratio or Adjustment Factor Project/Mixture DynamicModulus, ksi PSPA FWD I-85 AL, SMA Overlay 250 1.055 0.556 TH-23 MN, HMA Base 810 1.688 NA US-280 AL, HMA Base; Initial Area 650 1.407 3.939 US-280 AL, HMA Base; Supplemental Area 780 1.398 2.516 I-35/SH-130 TX, HMA Base 1,750 5.117 3.253 I-75 MI, Dense-Graded Type 3-C 400 0.919 NA I-75 MI, Dense-Graded Type E-10 590 0.756 NA US-47 MO, Fine-Graded Surface 530 1.158 NA US-47 MO, Coarse-Graded Base Mix 420 0.694 NA I-20 TX, HMA Base, CMHB 340 0.799 NA US-53 OH, Coarse-Graded Base 850 1.275 NA US-2 ND, Coarse-Graded Base, PG58-28 510 1.482 NA NCAT AL, PG67 Base Mix 410 0.828 NA NCAT FL, PG67 Base Mix 390 0.872 NA NCAT FL, PG76 Base Mix 590 1.240 NA NCAT AL, PG76 with RAP and Sasobit 610 1.3760 NA NCAT AL, PG76 with RAP and SBS 640 1.352 NA NCAT AL, PG67 with RAP 450 0.881 NA Overall Average Ratio 1.128 2.566 NOTES: 1. The adjustment factor or ratio was determined by dividing the dynamic modulus measured in the laboratory for the in-place temperature and at a loading frequency of 5 Hz by the modulus estimated with the NDT device. Read the entire page →
From page 13... ... NDT device and technology variability analysis for the fine-grained clay soils. Statistical Value Material Property NDT Devices Standard Error 95% Precision Tolerance Pooled Standard Deviation NDT Devices with Good Success Rates Based on Modulus or Volumetric Properties GeoGauge 2.5 4.9 1.8 Modulus, ksi DSPA 4.5 8.8 1.5 StructuralProperties Thickness, in. Read the entire page →
From page 14... ... After adjusting for laboratory conditions, all NDT devices that estimate resilient modulus resulted in low residuals (laboratory resilient modulus minus the NDT elastic modulus) Read the entire page →
From page 15... ... – The repeatability for the GPR device was found to be good and repeatable, with a value of 0.5 percent for air voids and 0.05 inches for thickness. • The PSPA moduli were comparable to the dynamic moduli measured in the laboratory on test specimens compacted to the in-place density at a loading frequency of 5 Hz and the in-place mixture temperature, with the exception of one mixture -- the US-280 supplemental mixture. Read the entire page →
From page 16... ... However, based on the results obtained, the ability to provide uniform compaction was verified and the rollers are believed to be worth future investments in monitoring the compaction of HMA mixtures. Limitations and Boundary Conditions • All NDT devices suggested for QA application, with the exception of the GPR and IC rollers, are point specific tests. Read the entire page →
From page 17... ... However, this technology can be used in the laboratory to measure the seismic modulus on test specimens during mixture design or verification prior to measuring the dynamic modulus in the laboratory. – A limitation of this technology is that the results (material moduli) Read the entire page →
From page 18... ... – It provided resilient modulus values that were correlated to the dry density over a diverse range of material types. – The normalized dispersion is less than for the other NDT devices that provide an estimate of stiffness. Read the entire page →
From page 19... ... Eliminating the laboratory resilient modulus tests from the calibration procedure will reduce its accuracy for confirming the design values, but not for identifying construction defects. For those agencies that do not have access to or the capability to perform resilient modulus tests, use of the FHWA-LTPP regression equations is an option that can be used to calculate the target resilient modulus at the beginning of construction. Read the entire page →
From page 20... ... HMA Mixtures • The PSPA is a self-contained NDT device that can be readily incorporated into a QA program for both control and acceptance testing of HMA mixtures. As noted for unbound materials, an advantage of this technology is that the device can be calibrated to the specific materials being tested during the mixture design stage for HMA mixtures. Read the entire page →
From page 21... ... In addition, the FWD has high variation in elastic modulus values, and those values are influenced by the strength of the underlying materials and layers. Recommendations The research team's recommendations are based on the evaluation of NDT devices for immediate and practical use in QA programs. Read the entire page →
From page 22... ... Research with the multi-antenna GPR device and proprietary data interpretation system should not be abandoned and should be validated in future studies. This system definitely shows promise in providing the volumetric properties for HMA mixtures. Read the entire page →

From page 1...

... Objectives The overall objective of NCHRP Project 10-65 was to identify NDT technologies that have immediate application for routine, practical QA operations to assist agency and contractor personnel in judging the quality of hot mix asphalt (HMA) overlays and flexible pavement construction.