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    <title>Transport Research International Documentation (TRID)</title>
    <link>https://trid.trb.org/</link>
    <atom:link href="https://trid.trb.org/Record/RSS?s=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" rel="self" type="application/rss+xml" />
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    <copyright>Copyright © 2026. National Academy of Sciences. All rights reserved.</copyright>
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    <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>RESEARCH REPORT IR-9: A STUDY OF PHYSICAL FACTORS AFFECTING THE DURABILITY OF ASPHALTIC PAVEMENETS</title>
      <link>https://trid.trb.org/View/99936</link>
      <description><![CDATA[THE FOLLOWING FACTORS AFFECTING IN-SERVICE ASPHALT HARDENING AND PAVEMENT DURABILITY ARE STUDIED: TRAFFIC DENSITY, MIXTURE COMPOSITION, AGGREGATE TYPE AND GRADATION, PAVEMENT DENSITY AND AIR VOIDS, AND ASPHALT CONSISTENCY IN CHEMICAL COMPOSITION AS DETERMINED BY THE ROSTLER METHOD OF ANALYSIS. PAVEMENT DURABILITY IS EVALUATED BY PERIODIC INSPECTION. ASPHALT HARDENING IS EVALUATED BY CHANGES IN COMPOSITION, PENETRATION, VISCOSITY AND DUCTILITY. THE WEARING COURSES IN THE FOLLOWING THREE PAVEMENT GROUPS ARE BEING STUDIED; (1) SWEEP PAVEMENTS CONSTRUCTED IN 1964-1965 WITH SIX DIFFERENT ASPHALTS AND A SINGLE AGGREGATE, (2) SIX PAVEMENTS CONSTRUCTED IN 1963 WITH 70/85 GRADE ASPHALTS AND THE FOLLOWING THREE AGGREGATE TYPES: GRAVEL AND SAND, LIMESTONE AND SAND, AND LIMESTONE, SAND, AND FLYASH, (3) FOUR PAVEMENTS LAID IN 1961-62 CONSTRUCTED WITH 70/85 PENETRATION GRADE ASPHALTS AND ONE WITH AN 85/100 PENETRATION GRADE ASPHALT USING SLAG AGGREGATE AND TWO PAVEMENTS AND ALL LIMESTONE AGGREGATE IN THE REMAINING TWO PAVEMENTS. TRENDS NOTED ARE THAT PAVEMENT VOIDS ARE DECREASING, ASPHALTENES INCREASING AND THE ASPHALTS GENERALLY HARDENING. TENTATIVE CONCLUSIONS GIVEN ARE: (1) HIGH AIR VOIDS ARE A MAJOR FACTOR CAUSING HARDENING OF ASPHALT INSERVICE, (2) HARDENING OF THE ASPHALTS IN THE PAVEMENTS OCCURS ONLY DURING THE WARMER MONTHS OF THE YEAR, AND (3) THE ROSTLER CHEMICAL PARAMETER IS NOT A USEFUL PREDICTOR OF ASPHALT HARDENING IN SERVICE.]]></description>
      <pubDate>Sat, 18 Mar 2000 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/99936</guid>
    </item>
    <item>
      <title>ASPHALT AND POLYMER MODIFIED ASPHALT PROPERTIES RELATED TO THE PERFORMANCE OF ASPHALT CONCRETE MIXES (WITH DISCUSSION)</title>
      <link>https://trid.trb.org/View/486635</link>
      <description><![CDATA[Some of the physical properties of polymer modified asphalts are exceptional when compared with conventional asphalts.  Does the exceptional performance in such tests equate to improved performance in asphalt mixes?  To address this question, five asphalts were studied:  three conventional asphalts representing the extremes of temperature susceptibility and two polymer-modified asphalts, each containing 5% polymer.  The following areas were studied:  rheology and physical properties; thermally induced cracking; flexural fatigue life; permanent deformation; aging - chemical and rheological changes; and binder tolerance to mix variables.  Discussion of each of these research areas is presented in this paper.  The study indicates that the exceptional performance of the polymer modified asphalts in tests such as temperature susceptibility, force ductility, toughness-tenacity and low temperature ductility does not correlate with exceptional performance of the modified binders in mixes.  Such tests may characterize modified binders, but they do not indicate improved performance in asphalt concrete mixes.  A focus of this research was to identify the properties of the binder which did correlate with mix performance properties.  Some conventional tests, and parameters derived from those tests, did correlate well with the mix performance.  The correlations are discussed.  A major result of this research was to establish that fundamental viscoelastic properties of the binders are well correlated with and help explain the behavior of the binders in asphalt concrete. Dynamic mechanical analysis of the five test asphalts was extensively used in the course of this study.  Measurements of the viscoelastic properties of the binders over a range of possible road temperatures is shown to be well correlated with the behavior of the binders in properly designed and prepared asphalt concrete.  It was interesting (and unexpected) to find that a conventional asphalt included in this study performed better than the polymer modified asphalts.  The proper balance of viscoelastic properties in the binder which is necessary for good mix performance is shown to exist naturally in some asphalts.  Data are shown which suggest that the proper balance occurs when an effective elastic network is created by natural, molecular associations.]]></description>
      <pubDate>Thu, 04 Jun 1998 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/486635</guid>
    </item>
    <item>
      <title>USING PYROLYZED CARBON BLACK (PCB) FROM WASTE TIRES IN ASPHALT PAVEMENTS (PART II: ASPHALT BINDER AND TEST ROAD). FINAL REPORT</title>
      <link>https://trid.trb.org/View/460181</link>
      <description><![CDATA[Scrap tires derived from automobiles have become a large environmental problem in the United States.  In this study, research is carried out to investigate the potential use of tire-derived pyrolyzed carbon black (PCB) from scrap tires as an asphalt cement modifier.  The asphalt cements used in this research were AC10 and AC20.  Penetration and softening point tests were performed to obtain the consistency of the asphalt cements.  The PCB, as provided by Wolf Industries, was combined with the asphalt cement in the following percentages:  5%, 10%, 15%, and 20%.  Penetration, softening point and ductility tests were performed to determine the temperature susceptibility of the modified binder as altered by the PCB.  In order that the results are comparable to previous testing, commercial carbon black purchased from CABOT Industry was also used as a modifier in the tests.  The same test procedures were applied to the asphalt cements modified by commercial carbon black.  The test results contained in this report illustrate the viability of the PCB as an asphalt modifier.  Recommendations are provided to facilitate further research on this particular project.  A preliminary assessment of a test road using the PCB is appended.]]></description>
      <pubDate>Thu, 11 Jul 1996 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/460181</guid>
    </item>
    <item>
      <title>DURABILITY OF PAVING ASPHALT - PART II, A STUDY OF THE ROSTLER AND HEITHAUS TEST METHODS FOR PAVING GRADE ASPHALTS</title>
      <link>https://trid.trb.org/View/97671</link>
      <description><![CDATA[THE ROSTLER ANALYSIS WAS PERFORMED ON RECOVERED ASPHALTS FROM THE ZACA-WIGMORE TEST ROAD AND ON A SERIES OF 85-100 PENETRATION GRADE ASPHALTS THAT WERE WEATHERED IN A LABORATORY INFRARED OVEN. ASPHALTENE, NITROGEN BASE, FIRST AND SECOND ACIDIFFINS AND PARAFFIN FRACTIONS WERE OBTAINED BEFORE AND AFTER AGING. THE HEITHAUS TEST WHICH PROVIDES A METHOD FOR MEASURING THE PEPTIZING POWER OF THE MALTENES AND THE PEPTIZABILITY OF THE ASPHALTENES IN ASPHALT TOGETHER WITH A MATHEMATICAL TREATMENT OF THESE FACTORS TO OBTAIN A STATE OF PEPTIZATION OF THE SYSTEM WAS APPLIED TO A SERIES OF 85-100 PENETRATION GRADE PAVING ASPHALTS. SOME OF THE FINDINGS OF THE STUDY ARE' /1/ THE ROSTLER COMPOSITIONAL PARAMETER, A RATIO OF NITROGEN BASES PLUS FIRST ACIDIFFINS TO PARAFFINS PLUS SECOND ACIDIFFINS ON THE ORIGINAL ASPHALT, APPEARS TO RELATE TO ABRASION LOSS AFTER WEATHERING OF THE ASPHALT IN AN INFRARED OVEN. THERE IS NO DEFINITE RELATION WHEN THIS PARAMETER IS COMPARED WITH THE SHEAR SUSCEPTIBILITY OF WEATHERED ASPHALTS AND ONLY A TREND OF A RELATION IS NOTED WHEN THE PARAMETER IS COMPARED WITH THE VISCOSITY OF THE RESIDUE AFTER A SPECIAL DURABILITY TEST, /2/ A FAIR TREND WAS FOUND WHEN SHEAR SUSCEPTIBILITY OF WEATHERED ASPHALTS WAS COMPARED TO A RATIO OF THE ASPHALTENE TO THE NITROGEN BASE CONTENT, /3/ A FAIRLY GOOD RELATION WAS FOUND BETWEEN THE PEPTIZABILITY OF THE ASPHALTENES AND THE VISCOSITY OF A SPECIAL DURABILITY TEST RESIDUE, /4/ NEITHER PEPTIZABILITY OF THE ASPHALTENES OR PEPTIZING POWER OF THE MALTENES CORRELATED WITH THE SHEAR SUSCEPTIBILITY OF THE RESIDUE BUT THE STATE OF PEPTIZATION OF THE SYSTEM PROVIDE A FAIRLY GOOD RELATION, AND /5/ THE RATIO OF NITROGEN BASIS TO PARAFFINS PROVIDED A DEFINITE TREND WHEN COMPARED TO THE PEPTIZING POWER OF THE MALTENES. /BPR/]]></description>
      <pubDate>Thu, 29 Dec 1994 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/97671</guid>
    </item>
    <item>
      <title>EMPIRICAL EVALUATION OF OLIVE HUSK IN ASPHALT CEMENT BINDER AND BITUMINOUS CONCRETE</title>
      <link>https://trid.trb.org/View/413795</link>
      <description><![CDATA[The results of an experimental study undertaken to evaluate quantitatively the effects of olive husk material on the properties of both asphalt cement binder and bituminous concrete mixtures are summarized.  Olive husk material was added to asphalt cement at four levels, ranging from 0 to 15% by total weight of binder.  For each husk-asphalt binder, physical behaviors of binder, including penetration at different temperatures, softening point, and ductility tests, were investigated.  The previous husk-asphalt binders were used to prepare husk-asphalt mixtures.  Three types of aggregates, including limestone, basalt, and granite, were used in this study.  For each level of husk-asphalt and aggregate type, Marshall, stripping, Marshall immersion, and indirect tensile tests were performed on the laboratory-made specimens with 50 blows on each face.  The results indicated that the addition of olive husk material up to 10% by total weight of binder would reduce the binder stiffness at low temperatures, increase the stiffness at high temperatures, and help reduce brittleness and temperature sensitivity of binders.  For all types of aggregate mixtures, the addition of olive husk material improved workability and stability and reduced the optimum binder content compared with asphalt mixtures without olive husk.  The inclusion of olive husk, up to 10%, in bituminous concrete mixtures improved stripping resistance, durability, water and temperature resistance, and resistance to both moisture and repeated freeze-thaw induced damage.]]></description>
      <pubDate>Wed, 23 Nov 1994 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/413795</guid>
    </item>
    <item>
      <title>YARDSTICK FOR GUIDANCE IN EVALUATING QUALITY OF ASPHALT CEMENT</title>
      <link>https://trid.trb.org/View/100738</link>
      <description><![CDATA[SAMPLES OF PAVING MIXTURES PRODUCED AT VARIOUS PLANTS AND USING MANY DIFFERENT ASPHALT CEMENTS FROM DIFFERENT CRUDES AND REFINERIES WERE TESTED BY THE LABORATORY. LOW TEMPERATURE DUCTILITY PROVIDES A METHOD OF MEASURING THE FUTURE SERVICES BEHAVIOR OF ASPHALTS AND THE PAVEMENTS IN WHICH THEY ARE INCORPORATED. AN IMPROVED LABORATORY METHOD PROVIDES A TOOL WHEREBY THE SIMULATION OF THE HOT-MIX PUGMILL OPERATION ON A LABORATORY BASIS CAN BE DUPLICATED. THIS PROCEDURE WILL ALLOW AN EVALUATION OF THE ASPHALT BEFORE IT IS PLACED. IT WAS DETERMINED THAT ANY PAVING MIXTURE WHICH CONTAINS AN ASPHALT WHICH SHOWS A DUCTILITY EXCEEDING 8CM SHOULD BE FREE FROM CRACKING.]]></description>
      <pubDate>Fri, 08 Jul 1994 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/100738</guid>
    </item>
    <item>
      <title>BEHAVIOR OF ASPHALTS IN THIN FILMS</title>
      <link>https://trid.trb.org/View/95107</link>
      <description><![CDATA[THE REPORT COVERS THE RESULTS OF TESTS ON THE RESIDUES OF ASPHALTS FROM MANY SOURCES THAT WERE OBTAINED IN THE THIN- FILM OVEN TEST (50 GRAM SAMPLE, APPROXIMATELY 1/8 INCH THICK HEATED AT 325 F. FOR 5 HOURS IN THE STANDARD VOLATILIZATION OVEN). DUCTILITY, SOFTENING POINT AND PENETRATION TESTS WERE MADE AND ON THE BASIS OF RESULTS OBTAINED, RECOMMENDATIONS FOR SPECIFICATION REQUIREMENTS FOR THE THIN-FILM OVEN TEST WERE SUGGESTED.]]></description>
      <pubDate>Fri, 10 Jun 1994 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/95107</guid>
    </item>
    <item>
      <title>DUCTILITY, FLOW LIMIT, AND ASPHALT PAVEMENT PERFORMANCE</title>
      <link>https://trid.trb.org/View/100919</link>
      <description><![CDATA[THE SIGNIFICANCE AND CONVENIENCE OF THE DUCTILITY TEST FOR DETERMINING SPECIFICATION COMPLIANCE, MANUFACTURING CONTROL, AND INVESTIGATION ARE REVIEWED. THE DOCUMENTED CORRELATION OF DUCTILITY WITH PAVEMENT PERFORMANCE AND THE PRESSING NEED FOR A RAPID AND SIMPLE TEST OF THIS PROPERTY WERE THE OCCASION FOR THE STUDY OF A TEST METHOD WHICH EVALUATES THE DUCTILITY OF ASPHALT CEMENT UNDER CONDITIONS WHERE COMPENSA- TION IS MADE FOR THE CONSISTENCY EFFECTS, ORDINARILY SO CRITICAL WITH DUCTILITY. TEST SPECIMEN CONSISTS ESSENTIALLY OF TWO STEEL SPHERES OR OTHER SURFACES BOUND TOGETHER WITH THE ASPHALT BEING TESTED. THE EVALUATION CONSISTS OF SUSPENDING ONE OF THE SURFACES OF THIS SPECIMEN FROM A RIGID SUPPORT IN A WATER BATH AND ATTACHING A SELECTED WEIGHT TO THE OTHER SURFACE WHILE HEATING THE WATER AT A CONSTANT RATE. THE SPECIMEN FAILS AT A TEMPERATURE THAT IS CHARACTERISTIC OF THE ASPHALT UNDER TEST, AND THE LENGTH OF THE THREAD FORMED IN THIS PROCESS AND THE TEMPERATURE ARE MEASURED AND RECORDED AS FLOW LIMIT AND FLOW TEMPERATURE, RESPECTIVELY. THE TEST PROCEDURE IS APPLICABLE TO THE CUSTOMARY PAVING ASPHALT CONSISTENCY RANGE. SAMPLES FROM TEST ROADS WHICH WERE DESIGNED TO ESTABLISH ASPHALT QUALITY FACTORS HAVE BEEN TESTED BY THIS PROCEDURE AND THOSE RESULTS ARE REPORTED AND DISCUSSED. THIS TEST METHOD GIVES MEANINGFUL DIFFERENCES IN VALUES WHERE THE ASPHALT DUCTILITY MEASURED AS THE FLOW LIMIT APPEARS TO BE A CRITICAL FACTOR IN THE PAVEMENT PERFORMANCE. FURTHERMORE, THE TEST METHOD IS SIMPLE, ECONOMICAL, COMPACT, AND RAPID. IT THEREFORE OFFERS PROMISE WHERE A RAPID TEST IS NEEDED OR WHERE ONLY SMALL SAMPLES OF ASPHALT ARE AVAILABLE FOR THE STUDY OF ASPHALT PROPERTIES AND THEIR CORRELATION WITH PAVEMENT PERFORMANCE. /AUTHOR/]]></description>
      <pubDate>Fri, 06 May 1994 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/100919</guid>
    </item>
    <item>
      <title>THE EFFECTS OF HOT STORAGE ON AN ASPHALTIC CONCRETE MIX</title>
      <link>https://trid.trb.org/View/100874</link>
      <description><![CDATA[THE EFFECTS OF PROLONGED STORAGE AT HIGH TEMPERATURES ON THE PROPERTIES OF BITUMINOUS PAVING MIX WERE INVESTIGATED. A FINE-GRADED BITUMINOUS PAVING MIX LAYERED WITH A TREATED ASPHALT CEMENT WAS STORED FOR FOUR DAYS. THROUGHOUT THIS STORAGE PERIOD, SAMPLES OF THE MIX WERE TAKEN FROM WHICH MARSHALL STABILITY TESTS WERE MADE. THE ASPHALT CEMENT WAS ALSO EXTRACTED FROM PORTIONS OF EACH SAMPLE AND TESTED FOR VISCOSITY, PENETRATION AND DUCTILITY TO MEASURE ANY HARDENING WHICH MAY HAVE OCCURRED DURING STORAGE. TEST RESULTS SHOW THAT THERE WAS A MARKED CHANGE IN THE PROPERTIES OF THE ASPHALT CEMENT DURING MIXING, BUT THAT ANY CHANGE WHICH MAY HAVE OCCURRED DURING STORAGE WAS PRACTICALLY NEGLIGIBLE. AN INSPECTION OF THE PAVEMENT CONSTRUCTED WITH THIS STORED MATERIAL INDICATED THAT FIVE MONTHS AFTER CONSTRUCTION, THERE WAS NO APPARENT DIFFERENCE BETWEEN THE PERFORMANCE OF THIS PAVEMENT AND THAT OF A PAVEMENT CONSTRUCTED WITH MATERIAL PRODUCED AT THE SAME TIME, BUT NOT SUBJECTED TO STORAGE. IT APPEARS THAT IN SOME CASES, BITUMINOUS PAVING MIXES MAY BE STORED FOR PROLONGED PERIODS WITHOUT DETRIMENTAL EFFECTS.]]></description>
      <pubDate>Sun, 01 May 1994 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/100874</guid>
    </item>
    <item>
      <title>CHANGES IN ASPHALT CEMENTS DURING PREPARATION, LAYING AND SERVICE BITUMINOUS PAVEMENTS</title>
      <link>https://trid.trb.org/View/100879</link>
      <description><![CDATA[A TWO-YEAR STUDY WAS CONDUCTED COOPERATIVELY BY THE TEXAS TRANSPORTATION INSTITUTE AND THE TEXAS HIGHWAY DEPARTMENT TO DETERMINE THE CHANGES THAT OCCUR IN ASPHALT BINDERS DURING THE PREPARATION, LAYING AND SERVICE OF HOT-MIXED PAVEMENT SURFACES. ASPHALT CEMENTS OF 85-100 PENETRATION GRADE FROM 9 PRODUCERS WERE STUDIED. BITUMEN FROM 4 REFINERIES WERE EACH USED AT TWO DIFFERENT SITES. DURING THE PREPARATION OF EACH PAVING MIXTURE, A SAMPLE OF THE ASPHALT CEMENT FLOWING TO THE HOT-MIX PLANT WAS OBTAINED, FOLLOWED BY SAMPLES OF MIXTURE ENTERING THE TRUCK AND AGAIN AT THE PAVING MACHINE. A SLAB WAS CUT FROM THE PAVEMENT ONE DAY AFTER LAYING AND COMPACTING AND ADDITIONAL SLABS WERE TAKEN AFTER TWO WEEKS, FOUR MONTHS, ONE YEAR AND TWO YEARS OF SERVICE. THE SLABS ON ARRIVAL FROM THE PAVING SITES WERE IMMEDIATELY TESTED FOR DENSITY AND PERMEABILITY TO AIR IN THE LABORATORY. EACH ORIGINAL AND RECOVERED ASPHALT WAS TESTED FOR VISCOSITY AT 77, 95, 140, AND 275 F. DUCTILITIES WERE MEASURED IN THE CALIFORNIA MICRO-DUCTILITY MACHINE AT 77 F. ASPHALTENE CONTENTS WERE DETERMINED ON ORIGINAL ASPHALTS AND RECOVERED SAMPLES AFTER 1 AND 2 YEARS OF SERVICE. DATA SHOW THAT A SMALL INCREASE IN VISCOSITY OCCURS DURING THE PREPARATION OF A PAVING MIXTURE AT TEMPERATURES OF 250-325 F, LAYING THE SURFACING, AND DURING THE FIRST TWO WEEKS OF SERVICE. FROM THEN ON UP TO TWO YEARS THE HARDENING OF ASPHALT PROCEEDS MUCH MORE RAPIDLY. THE INCREASE IN VISCOSITY VARIES AMONG THE DIFFERENT ASPHALTS COMBINED WITH DIFFERENT AGGREGATES UNDER VARIOUS SERVICE CONDITIONS. FOR EACH ASPHALT IT WAS FOUND THAT THE HIGHEST DUCTILITY VALUE AT 77 F WAS ALWAYS ASSOCIATED WITH A VISCOSITY OF 1 TO 3 MEGAPOISES AT 77 F. THE ASPHALTENE CONTENT USUALLY  INCREASES, BUT IN A FEW SITUATIONS AN UNEXPLAINED DECREASE IS NOTED. VISCOSITIES OF THE PETROLENES, SEPARATED FROM THE ORIGINAL ASPHALTS AND FROM THE MATERIALS EXTRACTED AFTER TWO YEARS OF SERVICE IN THE PAVEMENT, WERE DETERMINED AT 77 F. OVER THE PERIOD OF TWO YEARS THE PETROLENES INCREASED IN VISCOSITY FROM 1.05 TO 20.1 FOLD. THE INCREASE IN ASPHALTENE CONTENT AND PETROLENE VISCOSITIES AT 77 F WITH TIME DO NOT IN EVERY CASE EXPLAIN THE HARDENING OF THE FILMS OF ASPHALT CEMENT DURING SERVICE.]]></description>
      <pubDate>Sun, 01 May 1994 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/100879</guid>
    </item>
    <item>
      <title>SIGNIFICANCE OF TESTS FOR ASPHALTIC MATERIALS</title>
      <link>https://trid.trb.org/View/97990</link>
      <description><![CDATA[STANDARD ROUTINE TESTS ARE PRESENTED ON SPECIFIC GRAVITY, CONSISTENCY, SOLUBILITY, HEATING, DISTILLATION, DUCTILITY, CURING INDEX TEST AND VACUUM DISTILLATION TEST.]]></description>
      <pubDate>Thu, 21 Apr 1994 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/97990</guid>
    </item>
    <item>
      <title>PROGRESS REPORT ON CHANGING ASPHALT PROPERTIES OF IN-SERVICE PAVEMENTS IN PENNSYLVANIA</title>
      <link>https://trid.trb.org/View/100764</link>
      <description><![CDATA[THE CHANGES IN COMPOSITION, PENETRATION, DUCTILITY AND ABSOLUTE VISCOSITY WERE STUDIED FOR PERIODS UP TO THRITEEN MONTHS ON SAMPLES FROM OVERLAY PROJECTS CONSTRUCTED IN 1961 IN PENNSYLVANIA. THE PURPOSE INITIALLY WAS TO OBTAIN METHODS WHICH MIGHT PREDICT PERFORMANCE AND DURABILITY UNDER SERVICE CONDITIONS. BOTH ABSOLUTE VISCOSITY AND MICRO-DUCTILITY TESTS WERE USED AT VARIOUS TEMPERATURES AS PART OF THE INVESTIGATION OF NEW METHODS OF MEASUREMENT CHEMICAL ANALYSES OF THE ORIGINAL AND RECOVERED ASPHALTS WERE ALSO MADE, BUT NO SIGNIFICANT RELATIONSHIPS FOUND IN THE RESULTS TO DATE. EXCEPT FOR THE DUCTILITY-PENETRATION RELATIONSHIP, NO SIGNIFICANT RELATIONSHIPS TO PERFORMANCE ARE REPORTED IN THIS PROGRESS REPORT. SECONDARY RELATIONSHIPS BETWEEN THE VARIOUS TEST METHODS ARE REPORTED. /NAPA/]]></description>
      <pubDate>Thu, 24 Mar 1994 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/100764</guid>
    </item>
    <item>
      <title>MAKING THE MOST OF TEMPERATURE/VISCOSITY CHARACTERISTICS (REPRINT)</title>
      <link>https://trid.trb.org/View/380110</link>
      <description><![CDATA[One of the more difficult problems facing the Hot Mix Asphalt (HMA) contractor is dealing with the temperature susceptibility of asphalt cements.  Asphalt cement exhibits a wide range of viscosity over the temperature range experienced during production and construction of HMA, as well as during the service life of asphalt pavement.  HMA contractors need to use available data on asphalt cement properties in selecting the optimum temperatures for mixing, compacting and spraying. Asphalt cement refineries and suppliers generally test their materials and these test data are sometimes made available to the user agencies and contractors.  Numerous tests are conducted on asphalt cements to provide compliance with specifications. There are three different sets of asphalt cement specifications, based upon the viscosity of the original asphalt, the viscosity of aged asphalt, or the penetration.  Suppliers often provide data on all of these tests because various state or local agencies may use one or more specifications.  If these data are not available, the contractor should ask for viscosity-temperature information.  These test data are very useful to the contractor.  Methods are discussed within this publication whereby the penetration values can be converted to viscosity.  Then, a plot of viscosity can be made on standard charts (provided in the publication) at temperatures of 77 deg, 140 deg, and 275 deg F to provide the overall relationship for the range of temperatures normally encountered.  This information can be replotted in more detail and optimum temperatures can be developed for mixing, compacting, and spraying.  If the contractor needs to change asphalt cements, a "field calibration" can be made by using the viscosity-temperature charts.  Thus, if the change in asphalt cement is significant, the optimum construction temperatures can be readily determined and appropriate adjustments made. Finally, a discussion of other factors that may influence the viscosity-temperature relationship is presented.  Included here is the general effect of transport, hauling, and storage.  Also, the effect of additives and modifiers on HMA operations could be significant and these are covered briefly.  A review summary of key tests on asphalt cements is provided in an Appendix.]]></description>
      <pubDate>Fri, 15 Oct 1993 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/380110</guid>
    </item>
    <item>
      <title>CHANGES IN CHEMICAL COMPONENT TYPE COMPOSITION AND EFFECT ON RHEOLOGICAL PROPERTIES OF ASPHALTS. IN: AMERICAN CHEMICAL SOCIETY SYMPOSIUM ON CHEMISTRY AND CHARACTERIZATION OF ASPHALTS, AUGUST 1990, WASHINGTON, D.C.</title>
      <link>https://trid.trb.org/View/371130</link>
      <description><![CDATA[Component type compositions were changed by blending with fractionated materials and the effects of these changes on the rheological properties were studied. Thus, saturated hydrocarbons, naphthene aromatics, propane precipitated asphalts and waxes were blended with both good and poor paving asphalts. Changes in penetration index, low temperature stiffness, ductility and glass transition temperature were examined. The composition of a number of asphalts including air blown and visbroken asphalts and their rheological properties were also examined in these studies to obtain correlations.]]></description>
      <pubDate>Fri, 03 Sep 1993 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/371130</guid>
    </item>
    <item>
      <title>SOME EFFECTS OF RUBBER ADDITIVES ON ASPHALT MIXES</title>
      <link>https://trid.trb.org/View/348917</link>
      <description><![CDATA[The effects of three types of rubber on the behavior of asphaltic concrete (AC) mixes have been investigated by first determining the changes that rubber additives have on the properties of the bitumen binder.  Changes in penetration, softening point, and penetration temperature susceptibility with rubber-bitumen blends are reported. Force ductility tests were also carried out to investigate the changes in the properties of rubber-modified binders at low temperatures.  The Marshall method was used to determine changes in optimum binder content consequent to incorporation of rubber into the mix.  Flexural testing of beam specimens was carried out using cyclic loading to investigate the changes in the fatigue properties of AC mixes caused by the addition of rubber.  Within the limitations of the experimental work, the incorporation of the rubber into binders generally improved the properties of binders and mixes as determined by laboratory testing.]]></description>
      <pubDate>Mon, 31 Dec 1990 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/348917</guid>
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