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1 SUMMARY Ruggedness Testing of the Dynamic Modulus and Flow Number Tests with the Simple Performance Tester In Phases I and II of NCHRP Project 9-29, a detailed purchase specification for the Simple Performance Test System (SPT) was developed and two first article devices were procured and evaluated. This evaluation concluded that the SPT is a reasonably priced, user-friendly device for testing stiffness and permanent deformation properties of asphalt concrete. Additional work, however, was needed to further refine the SPT for use in routine practice. This additional work was undertaken in Phases IV and V of NCHRP Project 9-29. These phases of the project included four major activities directed at implementation of the SPT in routine practice: 1. Enhancement of the SPT to perform dynamic modulus master curve testing required for pavement structural design and analysis. 2. Procurement and evaluation of SPTs with dynamic modulus master curve testing capability. 3. Development of equipment for rapid preparation of test specimens for the SPT. 4. Ruggedness testing for the dynamic modulus and flow number tests conducted in the SPT. This report documents the ruggedness experiments that were performed in Phase V of the project. Two experiments were included in the SPT ruggedness testing. The first was a formal ruggedness experiment designed, conducted, and analyzed in accordance with ASTM E1169, Standard Guide for Conducting Ruggedness Tests. The second was an experiment designed to investigate whether there are significant differences in SPT data collected with equipment from the three manufacturers: Interlaken Technology Corporation (ITC); IPC Global, Ltd. (IPC); and Medical Device Testing Services (MDTS). The ruggedness and equipment effects experiments were performed separately for the dynamic modulus and flow number tests. The flow number and flow time tests are very similar. Both require similar control of stresses and temperature during the tests and similar accuracy in the measurement of deformations dur- ing the test. The results from the flow number test, therefore, can also be applied to the flow time test. Based on the findings from the ruggedness and equipment effects experiments, modifications to the equipment specification and test procedure were made to improve the quality of the test data and reduce variability. A final detailed purchase specification for the SPT and test procedures for the dynamic modulus and flow number tests were developed and are included as appendices to this report.