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18 Table 8. Proposed costs for SPTs. the salvageable components, reassemble the upgraded ma- chine, and return it to the United States. Since the first article Manufacturer Proposed Cost IPC Global $52,136 was being used extensively by the FHWA Mobile Asphalt Interlaken Technology Corporation $62,000 Laboratory to demonstrate the SPT, it was decided that the Medical Device Testing Services, Inc $67,500 upgrade should not be performed until another unit became James Cox and Sons, Inc. $68,000 available from the project for use in the FHWA Mobile Asphalt Laboratory. The upgrade was delayed several times development of their device and at their request, the contract because the other manufacturers failed to deliver their equip- was cancelled. Therefore, new devices were purchased from ment on time. IPC Global eventually offered to replace the IPC Global and Medical Device Testing Services in Phase IV Shedworks/IPC Global first article device with a new unit and of the project. credit the project approximately 70 percent of the original purchase price of the first article. This offer was accepted and the new unit was installed in the FHWA Mobile Asphalt Lab- 3.2.2 Upgraded First Article Devices oratory on November 15, 2006. The first article will be used by IPC Global for training. In Phase II of the project, first article devices were pur- chased from Shedworks/IPC Global and Interlaken Technol- ogy Corporation. When these devices were purchased, it was 3.2.2.2 Interlaken Technology Corporation envisioned that the SPT would be used only for fatigue and First Article rutting evaluations at intermediate and high pavement tem- The Interlaken first article device did not fully comply peratures. After the abbreviated dynamic modulus master with Version 1.1 of the specification. Version 1.1 incorpo- curve testing procedure was developed, it became apparent rated several changes that resulted from the first article eval- that the SPT also could serve as equipment for the develop- uation that was completed in Phase II of the project. The test ment of dynamic modulus master curves for pavement struc- chamber and the deformation measuring system for the tural design. Only two modifications were needed to make dynamic modulus test were the two major elements for the the first article devices comply with Version 2.0 of the equip- Interlaken first article that were not in compliance with Ver- ment specification: expand the low temperature control to sion 1.1 of the specification. The test chamber for the Inter- 39F and modify the control software to include 0.01 Hz load- laken first article was a large metal enclosure with a thick site ing. The estimated cost of these upgrades was small relative to glass that provided only limited view of the specimen and the cost of new equipment. Contracts were negotiated with instrumentation during testing. Users of the equipment IPC Global and Interlaken Technology Corporation to up- found this to be a major limitation during testing. The prob- grade the first article equipment to meet Version 2.0 of the lem was exacerbated by the lack of lighting in the cell. equipment specification. Because of this experience during the first article testing, Version 1.1 of the specification included a requirement that the specimen, platens, and instrumentation must be clearly 3.2.2.1 Shedworks/IPC Global First Article visible during testing. To comply with this requirement, the One of the first article devices evaluated in Phase II of the test chamber for the Interlaken first article had to be re- project was purchased from Shedworks, Inc. The equipment placed. Second, the Interlaken first article included a unique was manufactured by IPC Global and Shedworks represented extensometer system that was pushed into contact with the IPC Global in the United States. Shedworks and IPC Global specimen by small pneumatic cylinders. This unique defor- discontinued their relationship before Phase IV of the proj- mation measuring system was one of the factors leading to ect; therefore, the contract for the first article upgrade was the selection of Interlaken to supply a first article device. negotiated with IPC Global. The first article evaluation revealed that there was some slip The 39F temperature requirement presented a minor between the specimen and the extensometer system. As a problem for the Shedworks/IPC Global first article device. result, Version 1.1 of the specification included a standard The refrigeration unit needed to reach this temperature was glued gage point system for specimen deformation meas- too large for the first article frame and enclosure. The plan for urements. To comply with this requirement, Interlaken upgrading this device, therefore, involved removing the elec- had to design and install a new specimen deformation meas- tronics, test cell, and hydraulics from the first article and uring system. In addition to these major elements, the reinstalling them in a new frame and enclosure sized for Interlaken first article also had some unresolved software the new refrigeration unit. The upgrade was estimated to re- bugs. Thus, the Interlaken first article upgrade completed quire 4 to 6 weeks to ship the first article to Australia, remove in Phase IV addressed the following:

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19 1. Replacement of the test chamber with an acrylic chamber Figure 12 shows the interior of the test chamber. The heat that provided full view of the specimen, instrumentation, exchanger and associated fan are located at the back of the test and loading platens. chamber. The test chamber is large, measuring 15 in. diame- 2. Replacement of the original automated extensometer sys- ter by 21 in. high. It is raised and lowered by two hydraulic tem with a glued gage point system. This included the design actuators. Two hand switches are provided as a safety feature. of the gage point system as well as auxiliary equipment to Hand contact must be made with both of these switches for automate gluing of the gage points on the specimen. the test chamber to close. 3. Replacement of the original temperature control system Strains for the dynamic modulus test are measured by two with a new system designed to allow testing over the tem- magnetic LVDT extensometers mounted 180 apart as perature range of 39 to 140F. shown in Figure 13. Each extensometer includes two very 4. Various software modifications to control temperature, flexible springs that allow only vertical movement of the apply 0.01 Hz loading during the dynamic modulus test ends. Each extensometer includes a pin that centers the and to resolve outstanding software bugs. measuring system. When the pin is released, the extensome- ter is activated. To quickly and accurately mount the glued The first article was returned to Interlaken in November, gage points to the specimen, Interlaken designed the gluing 2003. Interlaken took approximately one year to complete the apparatus shown in Figure 14. This system has mechanical upgrade work and return the upgraded device to Advanced links that use the weight of the specimen to press the gage Asphalt Technology (AAT). points against the specimen at the correct gage length at the The upgraded Interlaken first article is shown in Figure 11. center of the specimen. The equipment is fairly large and operates on single phase Because several major changes were made during the up- 230 V power. Compressed air also is required for confined grade of the Interlaken first article, all of the specification testing. The Interlaken SPT consists of (1) a main wheeled cabinet (63 in. wide by 76 in. high by 31 in. deep) that houses the test chamber, the hydraulic pump, the hydraulic actua- tors, and associated control electronics; (2) a separate stan- dard laboratory bath (16 in. wide by 26 in. high by 17 in. deep) that provides temperature control for the test cell; and (3) a desk top computer for controlling the machine and collecting and analyzing test data. Separate 230 V power sup- plies are needed for the main cabinet and the laboratory bath. The laboratory bath is shown to the left of the test cell in Figure 11; the computer is located to the right of the main cabinet in Figure 11. Figure 11. Overall view of upgraded Interlaken SPT Figure 12. Open test chamber for the upgraded (main cabinet removed to show system hydraulics). Interlaken SPT.