InstroTek Industry News
InstroTek is now ISO/IEC 17025 Accredited
Founded in 1997, InstroTek, Inc. started as a company who would provide innovative and quality products to the construction industry to help contractors and agencies to test materials better and faster. In 2000, we began to provide nuclear gauge, SuperPave Gyratory, and laboratory scale calibrations for these very same customers. Thirteen years later, our commitment to quality still does not waver.
Starting in late 2008, we spent approximately 17 months working toward a prestigious goal—International Organization of Standardization (ISO) 17025 accreditation. In order to become accredited, InstroTek’s calibration facility had to meet the Perry Johnson Laboratory Accreditation ISO 17025 standards. PJLA, a globally recognized company providing laboratory accreditation, strictly adheres to the ISO guidelines for consistent quality. Receipt of the ISO 17025 accreditation assures customers that equipment, calibration methods, and reporting all follow standard operating procedures and are consistently accurate.
InstroTek’s ISO 17025 Accreditation provides formal recognition to the thoroughness of the employees work processes, documentation, and careful calibration procedures. The entire calibration team labored diligently to document each individual procedure, ending in the creation of an extensively detailed Quality Manual. In order to be accredited, PJLA auditors closely audited the facility, processes, procedures, and manual, comparing the documentation to actual practices.
PJLA reviewed details like:
Competence of staff
Validity and appropriateness of calibration methods
Traceability of measurements and calibrations to national standards
Suitability, calibration, and maintenance of reference standards
Organization of calibration environment
Sampling, handling, and transportation of calibrated devices
Quality assurance of calibration data
InstroTek, Inc. has become the only Nuclear Gauge Manufacturer worldwide to become ISO 17025 accredited. For the past 10 years we always practiced the basic concept associated with ISO 17025. However, we’ve gone beyond these humble beginnings by having every single step of our process clearly laid out and fine-tuned to meet PJLA’s standards. Whether it is customer interactions or equipment calibration, the ISO 17025 accreditation means our customers are receiving the benefit of reliable, consistent calibrations from InstroTek, Inc.
Committee Recommends Changes to AASHTO T-166
Under the direction of the Federal Highway Administration (FHWA) Asphalt Mix and Construction Expert Task Group, a subcommittee was charged to review current specific gravity measurement methods for aggregates and asphalt mixtures. Based on the review, which included current precision estimates, recent research studies and information provided by state agencies and equipment suppliers, the committee recommended the following revisions to AASHTO T 166 (bulk specific gravity of compacted specimens):
» Delete references to AASHTO T 275 (paraffin coating method) and replace with AASHTO T 331 (vacuum sealing method).
» Replace the current 2.0 percent water absorption limit for AASHTO T 166 specimens with a limit of 1.0 percent.
» Replace the incomplete precision statement contained in the current method (Section 13) with the precision estimates recommended by NCHRP 9-26.
As a result of the proposed revisions, AASHTO T 166 will essentially be limited for use with fine-graded mixtures, while AASHTO T331 will be used for coarse-graded and stone matrix asphalt (SMA) mixtures. This will significantly affect mix design and quality assurance testing for coarse-graded and SMA mixtures, as summarized below:
» AASHTO T331 results in higher air voids and VMA for coarse-graded and SMA mixtures--approximately 0.5 and 0.9 percent, respectively, at normal mix design compactive efforts, based on available data. To provide performance equivalent to or better than currently used mix designs, agencies should consider increasing VMA criteria by 0.5 percent for both coarse-graded SuperPave and SMA mixtures.
» AASHTO T331 also yields higher in-place air voids for coarse-graded and SMA mixtures--approximately 1.0 and 1.7 percent, respectively, based on available data. This change would require contractors to improve their compaction processes in order to meet existing in-place density requirements. Alternatively, agencies could adjust in-place density specifications consistent with the proposed measurement method so that density can be achieved with current compaction practices.
Spring 2010 NCAT Asphalt Technology News; v22, #1
The MiST™
A Revolutionary New Way to Test for Asphalt Stripping
MiST™ is an acronym for Moisture Induced Stress Tester. InstroTek, Inc. has designed a totally new, quick and the only rational method for testing moisture damage susceptibility of asphalt mixtures. The MiST is the latest innovation from InstroTek and unlike current test methods, is designed to simulate the stripping mechanisms that occur in HMA pavement layers.
For years, roadway engineers and asphalt contractors have been searching for a better method to test for the loss of bond or cohesion between the aggregate and the asphalt binder commonly know as “stripping” or “raveling." Current test methods can take days to complete and are not conducive to a production quality control environment. Results can also vary widely due to the lack of controls over the degree of saturation and temperature. More importantly, current test methods do not replicate the dynamics of pressures and scouring encountered in the field with repeated pore pressure created by vehicle tire passing over a wet pavement.
The InstroTek, Inc. MiST is a cyclic conditioning system that is designed to simulate the stripping mechanisms that occur in HMA pavement layers. The MiST is a stand alone unit that consists of a pressurized chamber that pushes and pulls water through a compacted asphalt sample, simulating the action of an automobile tire on the road. The tests can be performed at different pressures and temperatures to replicate different traffic and environmental conditions. The unit is completely automatic and results are ready in as little as four hours. Simply place your asphalt core sample in the MiST testing chamber, select your test parameters, press start and the unit does the rest. Upon completion of the test, the asphalt core is taken out of the testing chamber and evaluated for susceptibility to moisture damage.
Advantages:
ASTMs D6752 and D6857
Two New CoreLok ASTM standards, D6752 and D6857, are now in publication phase. Contact ASTM for copies of these standards.
ASTM D6752- "Standard Test Method for Bulk Specific Gravity and Density of Compacted Bituminous Mixtures Using Automatic Vacuum Sealing Method"
ASTM D6857- " Standard Test Method for Maximum Specific Gravity and Density of Bituminous Paving Mixtures Using Automatic Paving Mixtures"
CoreLok is now specified under Indiana Specification, Section 401 "Quality Control/Quality Assurance, QC/QA, Hot Mix Asphalt, HMA, Pavement", 2003.
University of Oklahoma at Norman has just completed a research study for Oklahoma DOT. The work is titled "An Alternate Method for the Determination of Asphalt Content". This method uses the bulk and apparent gravity results of combined aggregates, only possible with CoreLok, and maximum specific gravity of the mixture to determine the %AC. This method is environmentally friendly and requires much less testing time than the existing methods. The results reported in this research are accurate and repeatable. Please contact Dr. Zaman at University of Oklahoma or Mr. Ken Hobson at Oklahoma DOT for more information regarding this exciting new test method.
CoreLok is now successfully used for bulk gravity determination of Automobile brake components and in the mining industry for gravity determination of precious materials.