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1 CHAPTER 1 INTRODUCTION A key objective of NCHRP Project 9-19, "Superpave Sup- CD-ROM (CRP-CD-46) that contain (1) all the test data, port and Performance Models Management," was to develop mixture data, master curves, and master curve parameters simple performance tests for permanent deformation and obtained from the E* testing and analysis; and (2) all the test fatigue cracking for incorporation in the Superpave volu- and mixture data obtained from the Fn and Ft tests, including metric mix design method. NCHRP Report 465: Simple p (permanent strain at flow), r (recoverable strain at flow), Performance Test for Superpave Mix Design summarized p/r (from the Fn test), and compliance (from the Ft test). analytical and experimental work conducted originally at the Both plant mixes and laboratory-blended short-term oven- University of Maryland from 1995 to 2000 and then at aged mixes were tested under the project. Mixtures from Arizona State University (ASU) to (1) survey the range of MnRoad, NCAT Test Track, Indiana, Nevada I-80, Wes- potential simple performance test methods and (2) select the Track, FHWA-ALF, and Arizona DOT (ADOT) I-10 sites most promising methods for a field validation program. constituted the complete test matrix. Based on the results of the testing program in Project 9-19, ASU also conducted dynamic modulus, flow number, and three tests were recommended for further field validation as flow time testing for these other research projects: promising simple performance tests for permanent deforma- tion: (1) dynamic modulus, E*, determined by the triaxial 1. ADOT AC Mixture Stiffness Characterization Data- dynamic modulus test; (2) the flow number, Fn, determined base (Project #3 of the ASU-ADOT Research Program: from the repeated load test; and (3) the flow time, Ft, deter- "Development of Performance Related Specifications mined from the static creep test. for Asphalt Pavements in the State of Arizona") and Between 2001 and 2004, ASU and its subcontractors car- associated tasks (US-60 plant mixes and Two Guns lab ried out an extensive series of experiments to validate the blend and plant-mixed conventional and rubber mixes); dynamic modulus, flow time, and flow number tests with 2. Asphalt Rubber Demonstration Project (ADOT I-40 materials and data from accelerated pavement tests and full- site); scale field tests. In 2004, based on the results of these exper- 3. Performance Evaluation of Arizona Asphalt Rubber iments, the dynamic modulus test was recommended as the Mixtures Using Advanced Dynamic Material Charac- primary simple performance test for rutting. The flow num- terization Tests (ADOT I-17 site); ber test was recommended as a complementary procedure for 4. Alberta Asphalt Rubber Project (2002 AR Mix #1 and evaluating the resistance of a hot mix asphalt (HMA) mix 2003 AR Mix #2); design to tertiary flow; the flow time test was shown to be a 5. NCHRP 9-23 Project (Environmental Effects in simple, practical surrogate for the flow number test. Pavement Mix and Structural Design Systems); In subsequent work, ASU prepared a specification for 6. Development of an E* Master Curve Database for rutting, in the form of a Microsoft Excel spreadsheet, that Lime Modified Asphaltic Mixtures; determines a critical minimum E* value for HMA (based on 7. ADOT AC Mixture Permanent Deformation Database project-specific information on climate, traffic, pavement (Project #5 of the ASU-ADOT Research Program: structure, and layer depth); work to develop a simple speci- "Development of Performance Related Specifications fication for fatigue cracking will be completed in 2005. Both for Asphalt Pavements in the State of Arizona"); and specifications are based on a series of pavement design 8. ADOT AC Mixture Simple Performance Tests (Project examples pre-solved with the mechanistic-empirical pave- #7 of the ASU-ADOT Research Program: "Develop- ment design guide software developed in NCHRP Project ment of Performance Related Specifications for 1-37A, "Development of the 2002 Guide for the Design of Asphalt Pavements in the State of Arizona"). New and Rehabilitated Pavement Structures: Phase II." This report summarizes the theory behind the three For completeness all E*, Fn, and Ft results obtained through recommended simple performance tests, briefly describes the the testing and analysis of these other projects are also test methods, and presents appendixes on the included included in the appendixes contained on CRP-CD-46.