NDT Technology for Quality Assurance of HMA Pavement Construction (2009) / Chapter Skim
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Appendix B - Volume 1 - Procedural Manual
Appendix B - Volume 1 - Procedural Manual
Pages 87-112
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From page 87... ...
This appendix contains the Volume 1 -- Procedural Manual for NCHRP Project 10-65. A P P E N D I X B Volume 1 -- Procedural Manual 87
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From page 88... ...
88 Project No. 10-65 NONDESTRUCTIVE TESTING TECHNOLOGY FOR QUALITY CONTROL AND ACCEPTANCE OF FLEXIBLE PAVEMENT CONSTRUCTION FINAL REPORT VOLUME 1 -- PROCEDURAL MANUAL Prepared for: National Cooperative Highway Research Program Transportation Research Board National Research Council Of National Academies Prepared By: Harold L
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From page 89... ...
as well as the simple performance tests developed under NCHRP Project 9-19 in support of the Superpave volumetric mixture design procedure use modulus and other fundamental engineering properties for characterizing the materials. Nondestructive testing and evaluation offers a high production method of determining the structural and volumetric properties of pavement layers that are required for both mixture and structural design.
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From page 90... ...
3.1 SUMMARY OF EQUIPMENT TO MEASURE QUALITY CHARACTERISTICS The procedures presented herein use the dynamic modulus for HMA mixtures and resilient modulus for all unbound materials. The dynamic modulus is estimated with the Portable Seismic Pavement Analyzer (PSPA)
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From page 91... ...
The non-nuclear density gauges for unbound layers are not recommended for QC/QA at this point in time. Future updates and improvements will likely result in the use of these devices for process control.
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From page 92... ...
Non-Nuclear Density Gauge, PaveTracker
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From page 93... ...
Determine the Combined Variability for HMA Mixtures The combined variability includes the within-process variability and the target-miss variability or the precision of the target value. A reasonable combined variability for the initial use in setting the specification is provided for both HMA and crushed aggregate base layers in latter parts of this document.
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From page 94... ...
The target value of the control chart for each material is the average modulus measured in the laboratory. Both action and warning limits are normally included on the statistical control charts.
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From page 95... ...
D3,4 = Factors for computing control chart limits based on the range within the sample and dependent on the number of observations in the sample. 4.1 HMA MIXTURES AND LAYERS 4.1.1 Acceptance Testing of HMA Mixtures and Layers The dynamic moduli measured in the laboratory and the moduli measured with the PSPA were found to have a normal distribution, excluding areas with construction defects.
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From page 96... ...
Two options are provided: one for the case where the equipment is available for measuring the dynamic moduli and the second for the case where that equipment is unavailable. Option A -- Measure Dynamic Modulus Sample plant produced mixture from the control strip or at the beginning of the project and compact three test specimens using a Superpave gyratory compactor to the density or air void level targeted or specified.
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From page 97... ...
Figure 5. HMA Dynamic Moduli, Measured in the Laboratory or Calculated Using MEPDG Regression Equation Dynamic Modulus Regression Equation 0.1 1 10 100 0.1 1 10 100 Frequency, Hz.
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From page 98... ...
, as long as they were compacted to the expected or specified in-place target density or air void level. The seismic modulus is measured on test specimens for each temperature selected under step 3 using a device, known as a V-meter, containing a pulse generator and a timing circuit, coupled with piezoelectric transmitting and receiving transducers (see Figure 6)
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From page 99... ...
The method of calculating the design modulus is to develop a master curve based on the recommendations of NCHRP Report 465, "Simple Performance Test for Superpave Mix Design," or in accordance with the NCHRP Project 9-33 mixture design procedure. Figure 7.
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From page 100... ...
T = Test temperature. Equation 10 is used to translate the PSPA seismic moduli measured at varying surface temperatures during acceptance testing to the design modulus at the reference temperature and frequency.
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From page 101... ...
Field Adjustment Ratios HMA Mixture Type Mean StandardDeviation High binder content mixtures that exhibit tenderness, including SMA type mixtures 0.89 0.153 Harsh mixtures, coarse-graded mixtures including PMA 1.34 0.231 Table 1. Summary of the Average Ratios That Have Been Measured on Other HMA Mixtures Step 7: Acceptance Testing with the PSPA for Measuring Modulus of HMA Mixtures a.
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From page 102... ...
4.2.1 Quality Control Testing of HMA Mixtures and Layers The quality control plan uses the non-nuclear density gauges. The PaveTracker gauge was specifically used to determine the control limits and other required information; that gauge is referred to specifically within this document, but other non-nuclear density gauges can be used if found to be acceptable.
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From page 103... ...
If this condition occurs, the owner agency will likely require that the mat be removed and replaced. Step 3: Process Control Testing with Non-Nuclear Density Gauges a.
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From page 104... ...
Most contractors should have sufficient data for estimating this value in terms of setting the action and warning limits for the statistical control charts. Based on multiple operators and gauges, the following provides the recommended pooled standard deviation for density of the non-nuclear density gauges (PaveTracker)
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From page 105... ...
The optimum water content and maximum dry density are the target values for determining the resilient modulus of the unbound layer. Step 2: Determine Target Resilient Modulus The target value for acceptance should be the average resilient modulus used as the input to the MEPDG.
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From page 106... ...
Option A -- Measure Resilient Modulus Sample the unbound materials from the stockpiles or from the control strip and compact three test specimens. Measure the resilient modulus of the unbound material over the range of stress states in accordance with AASHTO T 307.
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From page 107... ...
These regression equations are shown below. Use of the regression equations is considered permissible because adjustments need to be made for the specific material.
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From page 108... ...
These relationships for these regression constants were developed from the FHWA-LTPP study (Von Quintus and Killingsworth 1998) Crushed Stone Base Materials: dryswLL γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ Pk 0001.0037.00088.0008.07632.0 8/31 (17)
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From page 109... ...
Step 3: Determine the Field Adjustment Factor (Adjusting Field to Laboratory Conditions) The GeoGauge results in a field modulus and needs be adjusted to be consistent with the structural design assumptions based on laboratory resilient modulus.
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From page 110... ...
Modulus-Growth Curve Measured with the GeoGauge Step 4: Use GeoGauge for Measuring Modulus of Unbound Layers for Acceptance and Conformance a. The material modulus should be measured on the in-place material using the GeoGauge in accordance with the manufacturer's recommendations.
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From page 111... ...
5.2.1 Quality Control Testing of Unbound Materials and Layers The quality control plan uses the GeoGauge to determine the control limits and other required information. The non-nuclear electrical density gauges require future improvements for use in process control.
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From page 112... ...
The following provides the overall pooled standard deviation until contractors develop sufficient information and data for setting their own control limits. Overall pooled standard deviation for setting the limits of statistical control charts for process control = 3.10 ksi
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