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    <title>Transport Research International Documentation (TRID)</title>
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    <copyright>Copyright © 2026. National Academy of Sciences. All rights reserved.</copyright>
    <docs>http://blogs.law.harvard.edu/tech/rss</docs>
    <managingEditor>tris-trb@nas.edu (Bill McLeod)</managingEditor>
    <webMaster>tris-trb@nas.edu (Bill McLeod)</webMaster>
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      <title>Transport Research International Documentation (TRID)</title>
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      <link>https://trid.trb.org/</link>
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    <item>
      <title>Spectrochemical Analysis, Spectroscopy, Spectrophotometers, Spectrophotometry, Photometry, Reflectometry, Colorimetry, Tri-Stimulus Color, Chromatography: Bibliography</title>
      <link>https://trid.trb.org/View/2559783</link>
      <description><![CDATA[This publication is a bibliography on spectrochemical analysis, spectroscopy, spectrophotometers, spectrophotometry, photometry, reflectometry, colorimetry, tri-stimulus color and chromatography as related to pavement materials. The bibliography contains 18 citations.]]></description>
      <pubDate>Sat, 02 Aug 2025 11:40:32 GMT</pubDate>
      <guid>https://trid.trb.org/View/2559783</guid>
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    <item>
      <title>Improved Infra-Red Procedure for the Evaluation of Calibrating Units</title>
      <link>https://trid.trb.org/View/1377962</link>
      <description><![CDATA[The National Highway Traffic Safety Administration (NHTSA) Model Specifications for Calibrating Units for Breath Alcohol Testers requires that calibration units submitted for inclusion on the NHTSA Conforming Products List for such devices be evaluated using one of three alternate procedures, all of which were developed at the Volpe Center. The preferred procedure uses a National Patent Analytical Systems, Inc. Datamaster breath alcohol analyzer instrument to analyze samples. This device is a non-dispersive infra-red spectrophotometer designed for breath (ethyl) alcohol analysis and is listed on the NHTSA Conforming Products List for evidential breath testers. The Datamaster instrument has been replaced with a Datamaster DMT instrument and the procedure has been improved by use of the simulator sample re-circulation feature that was not present in the older instrument. This document reviews the improved procedure and calculations.]]></description>
      <pubDate>Thu, 31 Dec 2015 09:06:32 GMT</pubDate>
      <guid>https://trid.trb.org/View/1377962</guid>
    </item>
    <item>
      <title>Correlation between Wavelength Dispersive X-Ray Fluorescence (WDXRF) Analysis of
Hardened Concrete for Chlorides vs. Atomic Absorption (AA) Analysis in accordance with
AASHTO T- 260; Sampling and Testing for Chloride Ion in Concrete and Concrete Raw
Materials, Procedure B, Acid-Soluble Chloride Ion Content by Atomic Absorption</title>
      <link>https://trid.trb.org/View/1313477</link>
      <description><![CDATA[A correlation between Wavelength Dispersive X-ray Fluorescence (WDXRF) analysis of Hardened  Concrete for Chlorides and Atomic Absorption (AA) analysis (current method American Association of State Highway and Transportation Officials (AASHTO) T-260, procedure B) has been found and a new method of analysis has been devised. With a Katanax Fluxer, a fused glass bead is prepared using only 1 gram of sample. Combined with a Lithium Borate flux, the sample is fused in a platinum crucible and poured into a platinum mold. The resulting bead is placed in the WDXRF for analysis. Utilizing the new methodology, a more precise and accurate chloride result is obtained and has cut the time of analysis in half. Also, the new methodology requires the use of less hazardous consumables, removing potential health and safety risks to employees. Once implemented the WDXRF method will lessen the turn around time from the cores taken from bridge decks, sent to the lab for evaluation for the total chloride measured at each depth, indicating the amount of salt present at that level. The higher the concentration of salt at greater depths indicates the potential for damage to the rebar. Recommendations for repairs are based on these results. With a faster time of analysis, results will allow the engineers to see the potential hazards before developing into a more serious issue.]]></description>
      <pubDate>Mon, 30 Jun 2014 09:41:45 GMT</pubDate>
      <guid>https://trid.trb.org/View/1313477</guid>
    </item>
    <item>
      <title>When Yellow Lights Look Red: Tinted Sunglasses on the Railroads</title>
      <link>https://trid.trb.org/View/1122212</link>
      <description><![CDATA[The authors measure transmission properties of safety sunglasses purchased by a major Canadian railroad company. The lenses’ “neutral gray tint” reportedly meets North American and European occupational safety standards for signal light transmittance. However railroad employees report yellow signal lights appearing red, when viewed through the sunglasses. Additionally, lenses show “a greenish brown tint” rather than neutral gray. Spectrophotometer measurements of lens transmission properties confirm a brown tint, which meets occupational sunglass transmittance standards for North America and Europe. Color shift calculations for railroad and road signal lights show “yellow signal chromaticity coordinates” shifting away from railroad yellow signal boundaries to appear red, confirming employee reports. Occupational sunglass transmittance standards are concluded to be inappropriate for the railroad industry because yellow wayside signal lights are redder and have a smaller angular size than traffic lights in North America or Europe.]]></description>
      <pubDate>Thu, 17 Nov 2011 08:15:28 GMT</pubDate>
      <guid>https://trid.trb.org/View/1122212</guid>
    </item>
    <item>
      <title>Mitigating the Effects of Organics in Stabilized Soils: Technical Report</title>
      <link>https://trid.trb.org/View/890516</link>
      <description><![CDATA[The Texas Department of Transportation has reported difficulty stabilizing soils bearing high and low concentrations of organic matter with lime. Problems include: the stabilizer disappearing over time, difficulty measuring organic matter (ignition oven), and rough pavement due to poor subgrade support. The researchers wanted to identify a good test to measure organic matter in soils and identify the problematic fraction of organic matter that causes problems with lime stabilization. Secondly, they wanted to determine what mechanism or mechanisms were responsible for organic matter interfering with lime stabilization. They developed a simple technique to measure the humic acid content of organic matter using a UV-Vis spectrophotometer. They also constructed hundreds of manufactured soils consisting of a humic acid standard mixed with different clay mineral standards, lime, and quartz sand. These soils were used to measure changes in engineering properties as well as monitor chemical changes to elucidate factors controlling reaction mechanisms. From the manufactured soils, the researchers determined that humic acid does interfere with lime stabilization by inhibiting the formation of Calcium Silicate Hydrate reaction products between the lime and clay minerals. This results in reduced unconfined compressive strength values for stabilized cores. The concentration of humic acid that inhibits the formation of pozzolanic reaction products is around 1 percent. Calcareous soils containing organic matter appear to respond better to lime stabilization than acid soils. This study was the first to provide direct evidence of the effects of organic matter on soil stabilization.]]></description>
      <pubDate>Wed, 10 Jun 2009 16:49:54 GMT</pubDate>
      <guid>https://trid.trb.org/View/890516</guid>
    </item>
    <item>
      <title>Comparison of Methods for Determining Specific Surface Area of Soils</title>
      <link>https://trid.trb.org/View/786697</link>
      <description><![CDATA[The present study was undertaken to compare the capabilities of four of the known methods; more specifically, N subset 2 adsorption, methylene blue (MB)-titration, MB-spot test, and ethylene glycol monoethyl ether (EGME) methods were evaluated to determine the specific surface area (SSA) of 16 different clayey soils. The study showed that N subset 2 adsorption method underpredicts the SSA of soils, especially for smectitic soils. No significant differences were observed between N subset 2 SSA, MB SSA-titration, or MB-spot test for kaolinitic soils. The SSA estimates of MB-titration and MB-spot test methods were highly correlated for all soils. The EGME method has a very different procedure from the MB methods; however, it was highly correlated with MB methods (r squared 2=0.95). The N subset 2 adsorption method had no correlation to other methods. The cation exchange capacity of tested soils was highly correlated to the SSA, as high as r squared 2=0.77. No unique relationship was determined between the clay fraction and SSA.]]></description>
      <pubDate>Wed, 23 Aug 2006 07:58:52 GMT</pubDate>
      <guid>https://trid.trb.org/View/786697</guid>
    </item>
    <item>
      <title>Test for the Presence of Asphalt Antistripping Additive</title>
      <link>https://trid.trb.org/View/778528</link>
      <description><![CDATA[A small device available commercially uses litmus paper and a spectrophotometer to analyze vapors from hot liquid asphalt binders and mixtures to determine the percentage of antistripping additive present. Approximately 60 five-point additive content–color index count regressions were performed on binders and mixtures to determine how well the device measured additive content. The regressions basically fit the quadratic format used by the manufacturer in the recommended calibration process. The regressions were best when the litmus color index count was calculated by subtracting the initial count of the blank strip from the final count after exposure from the mixtures. Changes to the instrument software and testing temperature were necessary as the investigation progressed to accommodate different grades of binders. After the planned testing was completed, some retesting of the binders was performed with the use of modified equipment and procedures. The changes appeared to improve the consistency of the results. Test results with mixtures were less accurate than for binders; however, if the vapor trap is modified as described, the accuracy for mixtures should be improved substantially. Because the test can be performed quickly, it would be possible to perform multiple tests on a sample. Multiple tests would increase the confidence of the test results.]]></description>
      <pubDate>Thu, 23 Mar 2006 09:19:43 GMT</pubDate>
      <guid>https://trid.trb.org/View/778528</guid>
    </item>
    <item>
      <title>TIME-TEMPERATURE STRENGTH-REACTION PRODUCT RELATIONSHIPS IN LIME-BETONITE-WATER MIXTURES</title>
      <link>https://trid.trb.org/View/121709</link>
      <description><![CDATA[THE INTERRELATION OF CURING TIME, CURING TEMPERATURE, STRENGTH, AND REACTIONS IN LIME-BENTONITE-WATER MIXTURES WAS EXAMINED. SAMPLES WERE MOLDED AT CONSTANT DENSITY AND MOISTURE CONTENT AND THEN CURED FOR PERIODS OF FROM 1 TO 56 DAYS AT CONSTANT TEMPERATURES THAT RANGED FROM 5 C TO 60 C. AFTER THE APPROPRIATE CURING TIME THE SAMPLES WERE TESTED FOR UNCONFINED COMPRESSIVE STRENGTH. THE BROKEN SAMPLES WERE THEN ANALYZED BY X-RAY DIFFRACTOMETER AND SPECTROPHOTOMETER TO DETERMINE THE IDENTITY OF THE REACTION PRODUCTS PRESENT AFTER EACH CURING PERIOD. IT WAS FOUND THAT THE STRENGTH GAIN OF LIME-CLAY MIXTURES CURED AT DIFFERENT TEMPERATURES IS DUE TO DIFFERENT PHASES OF THE COMPLEX REACTION, LIME & CLAY CSH /GEL/, CSH /II/, CSH /I/, TOBERMORITE. THE FARTHER THE REACTION PROCEEDS, THE HIGHER THE STRENGTH. THERE WAS ALSO EVIDENCE OF LATTICE SUBSTITUTIONS IN THE STRUCTURE OF THE CALCIUM SILICATE HYDRATES AT CURING TEMPERATURES OF 50 C AND HIGHER. NO CONSISTENT RELATIONSHIP BETWEEN TIME, TEMPERATURE, STRENGTH, AND THE S/A RATION OF REACTION PRODUCTS EXISTED, BUT IN ORDER TO ACHIEVE HIGH STRENGTHS THE APPARANT C/S RATION HAD TO BE LESS THAN TWO. THE CURING TEMPERATURE HAD AN EFFECT ON THE STRENGTH DEVELOPED BY A GIVEN AMOUNT OF REACTED SILICA IN THE CURED LIME-CLAY MIXTURE, BUT AT A GIVEN CURING TEMPERATURE THE CURED SAMPLE THAT HAD THE LARGEST AMOUNT OF REACTED SILICA GAVE THE HIGHEST STRENGTH. EVIDENCE WAS FOUND TO INDICATE THAT DURING THE CLAY REACTION SOME CALCIUM IS INDEED ADSORBED ONTO THE CLAY STRUCTURE RATHER THAN ENTERING INTO A POZZOLANIC REACTION. FINALLY, IT WAS DETERMINED THAT IT IS POSSIBLE TO DETERMINE THE AMOUNT OF SILICA AND ALUMINA IN LIME-CLAY REACTION PRODUCTS BY SPECTROPHOTOMETRIC ANALYSIS WITH SUFFICIENT ACCURACY FOR COMPARISON PURPOSES. THE SPECTROPHOTOMETRIC ANALYSIS TECHNIQUES USED DURING THE INVESTIGATION WERE SIMPLE AND WERE NOT TIME CONSUMING. /AUTHOR/]]></description>
      <pubDate>Sun, 15 Aug 2004 02:40:29 GMT</pubDate>
      <guid>https://trid.trb.org/View/121709</guid>
    </item>
    <item>
      <title>PARTIAL ANALYSIS OF SILICATE ROCKS BY ATOMIC ABSORPTION</title>
      <link>https://trid.trb.org/View/121080</link>
      <description><![CDATA[No abstract provided.]]></description>
      <pubDate>Sun, 15 Aug 2004 02:37:58 GMT</pubDate>
      <guid>https://trid.trb.org/View/121080</guid>
    </item>
    <item>
      <title>RAPID METHOD OF ANALYSIS OF BAUXITE</title>
      <link>https://trid.trb.org/View/119128</link>
      <description><![CDATA[A METHOD FOR THE RAPID ANALYSIS OF BAUXITE USING SPECTROPHOTOMETRY AND COMPLEXOMETRY IS DESCRIBED. RESULTS OF ANALYSES OF 8 BAUXITE SAMPLES, USING THIS METHOD, ARE COMPARED WITH RESULTS USING THE CLASSICAL METHOD AND CONFIRM THE ACCURACY OF THE RAPID METHOD. MODIFICATIONS WHICH ENABLE THE METHOD TO BE USED FOR THE ANALYSIS OF ROCKS AND CLAYS ARE ALSO DESCRIBED. /RRL/A/]]></description>
      <pubDate>Sun, 15 Aug 2004 02:13:01 GMT</pubDate>
      <guid>https://trid.trb.org/View/119128</guid>
    </item>
    <item>
      <title>FLAME METHOD FOR ESTIMATING CEMENT CONTENT OF SOIL-CEMENT AND POZZOLAN-CEMENT MIXTURES</title>
      <link>https://trid.trb.org/View/118561</link>
      <description><![CDATA[FLAME SPECTROPHOTOMETER IS EMPLOYED TO DETERMINE CALCIUM CONCENTRATION FROM WHICH CEMENT CONTENT IS ESTIMATED. PRELIMINARY EVALUATION INDICATES THAT METHOD IS A SIMPLE RAPID MEANS OF CHECKING CEMENT CONTENTS OF PLANT-BLENDED POZZOLAN CEMENT MIXTURES AS WELL AS THAT OF SOIL-CEMENT FIELD MIXES. BECKMAN FLAME SPECTROPHOTOMETER CONSISTING OF MODEL DU SPECTROPHOTOMETER AND MODEL 9200 FLAME ATTACHMENT WAS USED.]]></description>
      <pubDate>Sun, 15 Aug 2004 01:58:35 GMT</pubDate>
      <guid>https://trid.trb.org/View/118561</guid>
    </item>
    <item>
      <title>QUANTITATIVE DETERMINATION OF ASPHALT ANTISTRIPPING ADDITIVE</title>
      <link>https://trid.trb.org/View/702757</link>
      <description><![CDATA[A small device (StripScan) has been developed by InstroTech, Inc., that uses litmus paper and a spectrophotometer to analyze vapors from hot liquid asphalt binders and mixtures to determine the percentage of antistripping additive present.  Approximately 60 five-point additive content-color index count regressions were performed on binders and mixtures to determine how well the StripScan device measured additive content.  The regressions basically fit the quadratic format that is used by the manufacturer in the recommended calibration process.  The regressions were best when the litmus color index count was calculated by subtracting the initial count of the blank strip from the final count after exposure for the mixtures.  Changes to the instrument software and testing temperature were necessary as the investigation progressed to accommodate different grades of binders.  After the planned testing was completed, some retesting of the binders was performed using modified equipment and procedures.  The changes appeared to improve the consistency of the results; therefore, the author believes that additive content in binders can be determined within +/- 0.2% 95% of the time using the modified equipment and procedures.  Test results for mixtures were less accurate than for binders; however, if the vapor trap is modified as described, the accuracy for mixtures should be improved substantially.  Since the test can be performed quickly, multiple tests on a sample are possible.  This would increase the confidence of the test results.  Additional research and development is recommended and necessary before the device can be used for quality assurance testing.  An accuracy of +/- 0.1% is a worthy goal.]]></description>
      <pubDate>Tue, 27 Jul 2004 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/702757</guid>
    </item>
    <item>
      <title>DEVELOPMENT OF METHODS FOR DETERMINING AIRPORT PAVEMENT MARKING EFFECTIVENESS</title>
      <link>https://trid.trb.org/View/660370</link>
      <description><![CDATA[Paint markings on runways, taxiways, and ramps play an important role in preventing runway incursions.  Paint markings, however, deteriorate in terms of their conspicuity and must be replaced over time.  Presently, the conspicuity is determined by visual inspections of segments of these markings, but the validity of these inspections cannot always be confirmed.  This study was undertaken to develop a method for a quick and accurate evaluation of paint markings.  A manual method was required for eliminating subjectivity in the current method, and an automated method was developed for evaluation of larger surface markings over a vast airport area.  In addition, the study also established a threshold pass/fail limit for white and yellow paint.  It was found that for the manual method, three devices are required: a retro-reflectometer for determining retroreflectivity of the beads; a spectrophotometer  is required to determine whether or not the paint marking has faded out of tolerance; and a transparent grid is used to determine coverage of the paint.  If any one of these three tests fails, the pavement marking fails.]]></description>
      <pubDate>Wed, 27 Aug 2003 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/660370</guid>
    </item>
    <item>
      <title>LABORATORY AND FIELD PROCEDURES FOR MEASURING THE SULFATE CONTENT OF TEXAS SOILS</title>
      <link>https://trid.trb.org/View/660548</link>
      <description><![CDATA[Project 0-4240 was initiated to provide guidelines on how to effectively stabilize sulfate rich soils.  The first tasks in this project involved evaluating the various methods of measuring the sulfate content of soils both in the laboratory and in the field.  In the laboratory, two test procedures were investigated, namely Texas Department of Transportation (TxDOT) Test Method Tex-620-J gravimetric approach and the Ion Chromatography approach.  For this comparison, control samples with known sulfate contents were fabricated in the laboratory. The samples were treated with known amounts of fine-grained and coarse-grained sulfate crystals.  A range of samples was sent to TxDOT and several private laboratories.  In terms of both accuracy and repeatability, the researchers concluded that the Ion Chromatography approach is superior to TxDOT Test Method Tex-620-J.  Recommendations are submitted to improve the Tex-620-J procedure.  The main conclusion is that TxDOT should consider replacing Tex-620-J with the Ion Chromatography approach.  Sulfate swell problems are frequently localized, so substantial effort was placed on evaluating rapid field tests. Four potential tests were evaluated; two were found to provide good results.  Both the Colorimetric/Spectrophotometric and Conductivity tests should be considered for full-scale implementation.  A survey of both automated and map systems revealed that the existing geological maps provide a good first-cut indication of locations with potentially high sulfate contents.  The automated Soil Survey Geographic (SSURGO) maps hold great potential for future use, however, they are available for less than half of the Texas districts and some errors and inconsistencies were found.]]></description>
      <pubDate>Fri, 15 Aug 2003 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/660548</guid>
    </item>
    <item>
      <title>HARDENING OF ASPHALT IN HOT BITUMINOUS MIXES DURING THE HAULING PROCESS</title>
      <link>https://trid.trb.org/View/100786</link>
      <description><![CDATA[THE EFFECT OF ASPHALT HARDENING /IN HOT BITUMINOUS MIXES/ DURING HAULING ON THE BRITTLENESS AND LIFE OF AN ASPHALT CEMENT PAVEMENT IS BEING DETERMINED. MIX SAMPLES WERE TAKEN FROM HOT BITUMINOUS MIXES AT DIFFERENT TIMES AFTER PREPARATION AND FROM DIFFERENT SOURCES OF CRUDE. VISCOSITY MEASUREMENTS WERE MADE AT DIFFERENT TEMPERATURES TO DETERMINE ASPHALT HARDNESS. PENETRATION AND DUCTILITY TESTS WERE ALSO CONDUCTED. TO PROVIDE SOME INDICATION OF MOLECULAR CHANGES, THIN ASPHALT FILMS WERE PLACED BETWEEN SODIUM CHLORIDE PLATES AND TESTED ON AN INFRARED SPECTOPHOTOMETER. SIGNIGICANT HARDENING OCCURRED IN ALL OF THE ASPHALTS STUDIED. THE EXTENT OF HARDENING VARIED WITH THE ASPHALT SOURCE. ALSO ASPHALT VISCOSITIES VARIED SIGNIFICANTLY WITH THE POSITION AND DEPTH FROM WHICH THE MIX SAMPLE WAS TAKEN FROM THE TRUCK BED. ASPHALT SAMPLES TAKEN FROM THE UPPERMOST 1 IN. WERE GENERALLY SOFTER THAN THOSE IN THE REMAINDER OF THE MIX. ASPHALT DUCTILLITY DECREASED WITH INCREASE IN HAUL TIME.]]></description>
      <pubDate>Fri, 18 Nov 1994 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/100786</guid>
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