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Publication Number: FHWA-RD-07-052
Date: September 2007

Long Term Pavement Performance Project Laboratory Materials Testing and Handling Guide

Chapter 1. Introduction

1.1 History of LTPP Laboratory Testing

The Long Term Pavement Performance (LTPP) program was a twenty-year study begun in the late 1980s to evaluate pavement performance and the factors that affect it. LTPP’s goal was to provide the data necessary to explain how pavements perform and why they perform as they do. To meet this goal, nearly 2,500 pavement test sections were established on in-service highways throughout North America and hence subjected to real traffic loads and a wide range of environmental conditions. At each test section, general inventory, pavement performance monitoring, materials,traffic, climatic, and maintenance and rehabilitation data were collected.

A critical element to the successful accomplishment of the LTPP goal was the collection of accurate and reliable materials data. These data were needed to define the properties of each of the structural pavement layers of the test sections within the program.

Originally, the LTPP materials testing program under the direction of the Strategic Highway Research Program (SHARP) was conducted by one of five laboratory contractors as indicated by Figure 1.1. Testing of all portland cement concrete (PCC) materials was performed by one central contractor under the direct supervision offshore. Testing of the asphalt and unbound materials was performed by one of four laboratories under the management of the Regional Engineer assigned by SHRP to each of the four regions. The Regional Engineer was assisted in the contract management by the Regional contractor. The field sampling and laboratory testing for the General Pavement Studies (GPS) test sections was conducted under the contracts identified in Figure 1.1 with the exception of the resilient modulus testing and testing of overlays placed after these contracts ended. At the end of the SHRP oversight of the LTPP program, a five-year report was prepared which provides a complete review of the field sampling and laboratory testing activities performed under SHRP.(1)

The field sampling efforts were performed in accordance with the SHRP-LTPP Guide for Field Materials Sampling, Testing, and Handling, Operational Guide No. SHRP-LTPP-OG-006.(2)Each GPS experiment had a sampling plan specific to that experiment. The Field Guide provided each of these individual sampling plans. It also covered the requirements associated with sample naming, labeling, identification, and shipping.

The Specific Pavement Studies (SPS) projects differed from the GPS test sections in that each SPS project incorporated several test sections at a location. Field sampling and laboratory testing plans were developed for each specific SPS project. These sampling and testing plans were based on the general set of sampling and testing plans developed for each SPS experiment and as identified in the experiment specific guidelines. (See references 3–9.) Only the latest version of each of these documents was identified in the reference list. Revisions were made to most of these documents at some point during their use and can be found using the LTPP Guidelines for Data Collection.(10)

Figure 1.1 shows the organizational chart for the testing conducted under SHRP.  SHRP with the assistance of the LTPP Technical Assistance Contractor and Information Management oversaw all of the LTPP testing.  Testing pertained to Profile Services, Traffic Equipment, Data Analysis, Pavement Distress, and SHRP Falling Weight Deflectometer Testing where FWDs were operated by each Region.  Additionally, there were four SHRP Regional Engineers who oversaw the materials testing and drilling and sampling operations with the assistance of the four SHRP Region Coordination Office Contractors.  For the North Atlantic Region, the RCOC was PMS with PSI doing the testing and WEGS performing the drilling and sampling.  BRE, Inc. was the RCOC for the Southern Region.  Southwest and Law were the materials testing contractors and the drilling and sampling contractors.  The North Central RCOC was Braun Pvmt. Tech.  Braun Engineering was the materials testing contractor and the drilling and sampling contractor.  NCE was the Western Region RCOC.  Western Tech and ASU were the materials testing contractors and Chen-Northern was the drilling and sampling contractor.  A fifth materials testing contract under the oversight of a SHRP Project Manager was held by Law for performing the testing on the PCC materials from the LTPP sections.

Figure 1.1 Organizational Chart for Laboratory Testing Under Conducted SHRP

Testing for the LTPP program was carried out in accordance with the SHRP-LTPP Interim Guide for Laboratory Materials Handling and Testing (PCC, Bituminous Materials,Aggregates, and Soils), Operational Guide No. SHRP-LTPP-OG-004.(11) The Guide was prepared for the SHRP Laboratory Testing Contractors responsible for laboratory material handling and testing of material specimens and samples of asphalt materials, PCC, aggregates and soils under the supervision of the SHRP Regional Engineers and the SHRP Regional Coordination Office Contractor staff and SHRP Authorized Representatives. It was first release din November 1989 and served as a contract document providing the required information for sample receipt, testing plans for the GPS experiments, test protocols, sample disposal and invoicing.

Under the Federal Highway Administration (FHWA), testing efforts were consolidated under two contracts. The objective of these two contract laboratories was to perform testing of the SPS projects and complete the resilient modulus testing for the GPS test sections. Additional testing to be performed under these contracts included testing of any overlays constructed on the GPS test sections as time progressed. Due to lack of funding, the testing requirements for these laboratories were reduced to the resilient modulus and supporting tests for the SPS projects and GPS test sections. Because of these funding limitations, the remainder of the testing requirements were taken on by the State departments of transportation (DOTs) constructing the SPS projects and GPS overlays. After approximately one year, one of the FHWA contract laboratories released their contract due to potential conflict of interest with a separate contract held by the same company.

The Laboratory Materials Testing Guide was in a state of constant evolution over the life of the LTPP program and was revised over the years to more fully encompass the needs of the LTPP program. In 1993, updates were made to provide for the SPS project testing and appropriate forms for these projects. Updates were made to various testing procedures to clarify existing procedures. In particular, the protocols for resilient modulus testing for both the asphalt and unbound materials were re-written to provide a more robust means to perform these tests. Revisions to the Guide beginning in 1993 were made by directives from FHWA. The LTPP Customer Support Service Center may be contacted to obtain copies of these directives.

As part of a program assessment conducted in the late 1990s,a review of the available materials data indicated that there were gaps in the available data. An effort was undertaken to fill in these gaps of missing data and improve the overall quality of the available data. As part of this effort, the document LTPP SPS Materials Data Resolution: Update and Final Action Plan was developed to fully document the existing gaps and the proposed methods for resolving them.(12) Due to further funding limitations, some of the desired testing originally identified in the Materials Action Plan (MAP) was removed from the plan. The FHWA awarded a laboratory contract to perform the testing identified in the MAP.

The objective of this document is to provide information to analysts regarding the methods used in obtaining research quality laboratory data for the LTPP program.

1.2 Document Outline

This version of the laboratory materials testing guide represents a major revision to previous versions of the guide. This version consists of five chapters. The objective of the first chapter is to provide an overview of the history of the guide and the objective of this version. The second chapter provides a summary of the quality control/quality assurance (QC/QA) program used by the LTPP program to assure the quality of the results. Chapter 3 provides the series of forms (L01 to L04) used to alert the FHWA of receipt of data and assign tests to individual samples. Chapter 3 also provides the methods used in splitting samples to obtain the sample used for testing. Chapter 4 provides the protocols, associated forms, and codes used in completion of those forms. Finally, Chapter 5 provides the guidelines for completing the section layering information in the L05 series forms. The last two sections of the document contain a glossary of common terms used throughout the Guide and the references for other relevant LTPP documents.

As the protocols used by the laboratories in performing testing for the LTPP program provide the largest portion of this document, a list of these protocols, test designations, and titles are provided in Table1.1. Some of the protocols listed in Table 1.1 were developed as new tests to be performed as part of the action plan to provide a more complete set of the materials data in the LTPP Pavement Performance Data Base (PPDB) for the SPS projects. Due to funding issues, these new tests were eliminated from the MAP and no data were collected using these protocols (P27, P28, P29, and P70). Additionally, the protocols beginning with the letter "H" were used for testing materials from the SPS-3 and SPS-4 experiments concerning the effectiveness of maintenance on asphalt concrete pavements and jointed concrete pavements,respectively.

Table 1.1 List of Protocols and QC/QA Checks
Protocol Designation Title
P01 AC01 Test Method for Visual Examination and Thickness of Asphaltic Concrete Cores
P02 AC02 Test Method for Bulk Specific Gravity of Asphaltic Concrete
P03 AC03 Test Method for Maximum Specific Gravity of Asphaltic Concrete
P04 AC04 Test Method for Asphalt Content of Asphaltic Concrete
P05 AC05 Test Method for Moisture Susceptibility of Asphaltic Concrete
P07 AC07 Test Method for Determining the Creep Compliance, Resilient Modulus and Strength of Asphalt Materials Using the Indirect Tensile Test Device
P11 AG01 Test Method for Specific Gravity and Absorption of Extracted Coarse Aggregate
P12 AG02 Test Method for Specific Gravity and Absorption of Extracted Fine Aggregate
P14 AG04 Test Method for Gradation of Aggregate Extracted from Asphaltic Concrete
P14A AG05 Test Method for Fine Aggregate Particle Shape
P21 AE01 Test Method for Recovery of Asphalt from Solution by Abson Method
P22 AE02 Test Method for Penetration of Extracted Asphalt Cement at 77°F (25°C) and 115°F (46°C)
P23 AE03 Test Method for Specific Gravity of Extracted Asphalt Cement
P24# AE04 Test Method for Viscosity of Asphalt Cement at 77°F (25°C) with Cone and Plate Viscometer
P25 AE05 Test Method for Kinematic and Absolute Viscosity of Extracted Asphalt Cement
P27* AE07 Standard Test Method for Determining the Rheological Properties of Asphalt Binder Using a Dynamic Shear Rheometer (DSR)
P28* AE08 Test Method for Determining the Flexural Creep Stiffness of Asphalt Binder Using the Bending Beam Rheometer (BBR)
P29* AE09 Test Method for Determining the Fracture Properties of Asphalt Binder in Direct Tension
P31 TB01 Test Method for Identification and Description of Treated Base and Subbase Materials, and Determination of Type of Treatment
P32 TB02 Test Method for Determination of Compressive Strength of Other than Asphalt Treated Base and Subbase Cores
P41 UG01, UG02 Test Method for Gradation of Unbound Granular Base/Subbase Materials
P42 SS02 Test Method for Hydrometer Analysis of Subgrade Soils
P43 UG04, SS03 Test Method for Determiation of Atterberg Limits of Unbound Granular Base and Subbase Materials and Subgrade Soils
P44 UG05 Test Method for Moisture-Density Relations of Unbound Granular Base and Subbase Materials
P46 UG07, SS07 Test Method for Resilient Modulus of Unbound Granular Base/Subbase Materials and Subgrade Soils
P47 UG08 Test Method for Classification and Description of Unbound Granular Base/Subbase Materials
P48 UG09 Test Method for Permeability of Unbound Base and Subbase Materials Under Constant Head Using a Rigid Wall Permeameter
P49 UG10, SS09 Test Method for Determination of Natural Moisture Content
P51 SS01 Test Method for Sieve Analysis of Subgrade Soils
P51A SS01 Test Method for Dry Sieve Analysis of Subgrade Soils
P52 SS04 Test Method for Classification and Description of Subgrade Soils
P54 SS10 Test Method for Unconfined Compressive Strength of Subgrade Soils
P55 SS05 Test Method for Moisture-Density Relations of Subgrade Soils
P56 SS08 Test Method for Density of Subgrade Soils
P57 SS11 Test Method for Measurement of Hydraulic Conductivity of Saturated Porous Materials Using a Flexible Wall Permeameter
P60 SS12 Test Method for Determining Expansive Soils
P61 PC01 Test Method for Determination of Compressive Strength of PCC Cores/Cylinders
P62 PC02 Test Method for Determination of Splitting Tensile Strength of PCC Cores/Cylinders
P63 PC03 Test Method for Determination of the Coefficient of Thermal Expansion of PCC
P64 PC04 Test Method for Determination of Static Modulus of Elasticity of PCC Cores
P65 PC05 Test Method for Density of PCC
P66 PC06 Test Method for Visual Examination and Thickness of PCC Cores
P67 PC07 Test Method for Determination of the Shear Strength at the Interface of Bonded Layers of Concrete
P68 PC08 Test Method for Microscopical Determination of Parameters of the Air-Void System in Hardened Concrete Using the Linear Traverse (Rosiwal) Method
P69 PC09 Test Method for Flexural Strength of Concrete (Using Simple Beam with Third-Point Loading)
P70* PC10 Test Method for Petrographic Examination of Hardened Concrete
P71 UG13, SS13 Test Method for Specific Gravity of Unbound Materials
P72 UG14, SS14 Test Method for Use of the Dynamic Cone Penetrometer in Shallow Pavement Applications
H01L+ AC08 Preparation of Asphalt Cores for Aging Tests
H02L+ AE01S Recovery of Asphalt from Solution by Abson Method
H03L+ AE02S Penetration of Bituminous Materials
H04L+ AE06S Viscosity of Asphalts
H05L+ SC01 Standard Methods of Testing Emulsified Asphalts
H06L+ SC02 Plastic Fines in Graded Aggregates and Soils by Use of the Sand Equivalent Test
H07L+ SC03 Testing Crushed Stone, Crushed Slag, and Gravel for Single or Multiple Bituminous Surface Treatments
H08L+ SC04 Determination of Flakiness Index of Aggregates
H09L+ SC05 Design, Testing, and Construction of Slurry Seal
H10L+ SC06 Test Method for Measurement of Excess Asphalt in Bituminous Mixtures by Use of a Loaded Wheel Tester and Sand Cohesion
H11L+ SC07 Wet Stripping for Cured Slurry Seal Mixes
H12L+ SC08 Determination of Slurry System Compatibility
H13L+ SC09 Mixing, Setting, and Water Resistance Test to Identify "Quick Set" Emulsified Asphalts
H14L+ SC10 Sieve Analysis of Seal Coat Aggregates
H15L+ SC11 Chip Seal Mix Design
H16L+ CS01 Joint Sealants, Hot-Poured, for Cement and Asphalt Pavements
H17L+ CS02 Joint Sealants, Silicone
H18L+ US01 Compressive Strength of Hydraulic Cement Mortar
H19L+ SC12 Determination of Asphalt Content from Slurry Seal Sample
H20L+ SC13 Accelerated Polishing of Aggregate Using the British Wheel

Notes: # Testing using protocol P24 was cancelled effective December 1997.
* No testing was performed for the LTPP program using this protocol.
+ These tests were used for testing samples from the SPS-3 and SPS-4 projects exclusively.

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