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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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    <item>
      <title>COMPACTION OF BITUMINOUS PAVEMENTS</title>
      <link>https://trid.trb.org/View/39377</link>
      <description><![CDATA[For satisfactory compaction at the lowest cost, the compactibility of bituminous mixtures for different cooling rates and rolling processes must be known, and a quick means of determining the degree of compaction must be available. The nuclear method subjects the pavement to gamma radiation, the amounts absorbed and back-scattered being a measure of density. The instrument tested has a probe containing isotope cs 137, back scatter being detected by GM tubes. Agreement between paraffin and nuclear methods was good, standard deviation being 0.02-0.03 g/cm3. For efficient utilisation of equipment, time available for compaction must be known. This is the interval between stability and stiffness of the asphalt. Lower limit depends on compactibility, rolling process and cooling process. In field tests the temperature was measured by thermistors placed in the pavement. Good agreement was obtained between field results and theoretical analysis. Field tests in 1965 with variable rolling parameters resulted in the following rolling programme: 1. Rolling to start as soon as possible by 2 static rollers in tandem, 2. At least 8 and preferably 12 passes, 3. Speed of approx. 5 km/h. Average degree of compaction was 97-100%, standard deviation 1%. Resistance to wear by studs was improved by 30%. /TRRL/]]></description>
      <pubDate>Tue, 15 Jul 2003 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/39377</guid>
    </item>
    <item>
      <title>IN-SITU DETERMINATION OF MOISTURE IN ROAD PAVEMENT BY NUCLEAR METHODS</title>
      <link>https://trid.trb.org/View/185624</link>
      <description><![CDATA[The use of neutron moisture probes to determine moisture in compacted pavement layers has been studied on samples representative of those used by the New South Wales Department of Main Roads for roadway construction.  The aim of this work was to measure the average moisture content of the upper layer (15-20 cm thick) with minimum interference from moisture in underlying layers. Sub-surface probes using high (alpha -Be) and low (alpha -Li) energy neutron sources were examined; conventional alpha -Be sources in specially designed compact probes should result in an error due to base moisture and density variations of less than 0.4 wt % moisture. As this error is probably less than those due to sampling and geometry variations in the field, such a probe should be sufficiently accurate for DMR requirements. If less sensitivity to base moisture is required, the alpha -Li source will reduce this sensitivity by a factor of about 1.4.  (Atomindex citation 12:634552)]]></description>
      <pubDate>Fri, 31 May 1996 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/185624</guid>
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    <item>
      <title>LABORATORY DENSITY MEASUREMENTS OF BITUMINOUS MIXES BY GAMMA-RAY PROBE</title>
      <link>https://trid.trb.org/View/370819</link>
      <description><![CDATA[An experimental study that evaluated the feasibility of applying a twin-probe gamma-ray gauge for density measurements of cylindrical bituminous specimens is described.  Major considerations related to the operational features of the gauge and the characteristics of the composite structure of bituminous mixtures are highlighted.  Three bituminous mix types--namely, sand asphalt, dense-graded mix, and open-graded mix--were included.  The measurement precision and accuracy characteristics of the gauge with respect to the different mix types were examined.  It was found that the precision and accuracy of gauge-determined densities varied with the types of mix tested.  Better precision and accuracy were achieved with specimens that had more uniform density distribution within the mass and with specimens that were less porous.  Recommendations concerning the use of gamma-ray probes for laboratory density measurements of bituminous paving mixtures are made.  An illustration showing the ability of the twin-probe gauge to determine the density profile of a tall specimen is presented.]]></description>
      <pubDate>Thu, 25 Nov 1993 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/370819</guid>
    </item>
    <item>
      <title>HYDROLOGIC BALANCE MODEL USING NEUTRON PROBE DATA</title>
      <link>https://trid.trb.org/View/289891</link>
      <description><![CDATA[A hydrologic balance model is described that incorporates measured irrigation and precipitation amounts in order to estimate evapotranspiration from the monitored soil moisture status.  The application of the model under typical field conditions is described.  It is applied in a regional evapotranspiration experiment containing 12 neutron probe sites in a test grid of 100 km by 100 km.  The model performs a hydrologic balance keeping the surface layer separate from the rest of the soil profile.  Various model options are available for selection of field capacity and maximum periods of drainage of the soil profile.]]></description>
      <pubDate>Sat, 31 Dec 1988 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/289891</guid>
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    <item>
      <title>IN-SITU DETERMINATION OF MOISTURE IN ROAD PAVEMENT BY NUCLEAR METHODS</title>
      <link>https://trid.trb.org/View/191348</link>
      <description><![CDATA[The use of neutron moisture probes to determine moisture in compacted pavement layers has been studied at the AAEC Research Establishment on samples representative of those used by the New South Wales Department of Main Roads (DMR) for roadway construction.  The aim of this work was to measure the average moisture content of the upper layer (15-20 cm thick) with minimum interference from moisture in underlying layers.  Sub-surface probes using high (alpha-be) and low (alpha-li) energy neutron sources were examined; conventional alpha-be sources in specially designed compact probes should result in an error due to base moisture and density variations of less than 0.4 weight per cent moisture.  As this error is probably less than those due to sampling and geometry variations in the field, such a probe should be sufficiently accurate for dmr requirements. If less sensitivity to base moisture is required, the alpha-li source will reduce this sensitivity by a factor of about 1.4.  (Author/TRRL)]]></description>
      <pubDate>Sun, 30 Oct 1983 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/191348</guid>
    </item>
    <item>
      <title>METHODICAL COMPARISON OF NEUTRON DEPTH PROBES AND LONG-TERM SOIL MOISTURE MEASUREMENTS ON LOESS, SANDY LOESS, AND BOULDER CLAY</title>
      <link>https://trid.trb.org/View/190523</link>
      <description><![CDATA[Three measuring instruments were tested.  0.05 mCi Cf-252, 100 mCi Am-241/Be, 500 mCi Am-241/Be.  The advantages--measurement in undisturbed soil profiles, large depths of measurement, reproducibility of measurements in the same place over several years--and the disadvantages--radiation protection, resolution, variations of measured volume in dependence of moisture, background influences etc.--have been critically checked by experiment. In addition, annual soil moisture curves have been measured over two years by parallel use of the free probes on a loess, sandy loess, and boulder clay site.  The results were compared and discussed with a view to the soil water dynamics of these sites.  (Atomindex citation 12:613723).]]></description>
      <pubDate>Tue, 30 Aug 1983 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/190523</guid>
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    <item>
      <title>MOISTURE AND DENSITY MEASUREMENTS IN CLAY SOILS</title>
      <link>https://trid.trb.org/View/167449</link>
      <description><![CDATA[As part of a comprehensive study of soil moisture and density changes in expansive clay soils, neutron moisture and gamma density probes have been used over the past 20 years by the Prairie Regional Station, Division of Building Research, National Research Council of Canada. In order to achieve the desired accuracy levels for these research studies it was necessary to carry out an extensive field calibration program.  Gravimetric moisture and density measurements were compared with the nuclear probe measurements at several field sites in Winnipeg, Manitoba, and in Regina, Saskatoon and Eston, Saskatchewan.  A specially designed concentric power auger sampler was used in these calibration studies.  This paper provides descriptions of the equipment and techniques used, the results of statistical studies of the calibration data, and evaluation of the accuracy of measurements using the derived calibration curves and those supplied by the manufacturer of the nuclear probes.  Thorough calibration for specific soil profiles can make nuclear depth probes suitable for non-destructive testing and monitoring of soil moisture and density and, indirectly, provide information on degree of saturation in situ.  (Author)]]></description>
      <pubDate>Wed, 16 Sep 1981 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/167449</guid>
    </item>
    <item>
      <title>INTERNATIONAL SYMPOSIUM ON GRANULAR MATERIALS - BUDAPEST, 9-12 OCTOBER 1978. STUDY AND INVESTIGATION METHODS FOR PLUTONIC AND LOOSE ROCK DEPOSITS</title>
      <link>https://trid.trb.org/View/160220</link>
      <description><![CDATA[Since 1969 extensive research has been carried out into methods of investigating deposits so as to minimize unexpected drawbacks in quarrying.  New trends arose during the last few years as regards solid rock deposits and alluvial deposits: vprh drilling machine with sampling core drilling device for immersed sand-gravel; - natural and selective radioactive probes (thorium-potassium) for studying the various parameters of a deposit; - mta method. (TRRL)]]></description>
      <pubDate>Wed, 15 Apr 1981 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/160220</guid>
    </item>
    <item>
      <title>DENSITY AND MOISTURE CONTENT LOGGING - FIRST GENERATION OF NUCLEAR PROBES</title>
      <link>https://trid.trb.org/View/154330</link>
      <description><![CDATA[This report summarizes laboratory studies of nuclear logging probes for measuring the in-situ bulk density and moisture content in boreholes.  The measurement of bulk density is effected by means of gamma rays and the moisture content by thermalization of rapid neutrons. To develop the probes the authors used the principle of double detection.  By combining data from two sensors, it is possible to partly ignore the irregularities of the borehole diameter.  The first part of the report deals with the development of the bulk density measuring probe which uses gamma rays: definition of the radio-element sensors used, source-sensor distance, mechanical filters and discrimination thresholds, calibration method.  Part 2 is devoted to the development of the moisture content measuring probe which uses the thermalization of rapid neutrons and facilitates study of the influence of the source-sensor distance and borehole diameter, and the calibration method.  The prototype developed from those tests is presented.  The importance of measurement conditions is examined for the two devices. (TRRL)]]></description>
      <pubDate>Mon, 27 Oct 1980 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/154330</guid>
    </item>
    <item>
      <title>NONDESTRUCTIVE TESTING OF PAVEMENTS AND PAVEMENT BASES. 1964-MARCH, 1980 (CITATIONS FROM THE NTIS DATA BASE)</title>
      <link>https://trid.trb.org/View/155537</link>
      <description><![CDATA[Nondestructive methods for quality assurance of pavements and pavement bases are investigated in these Government-sponsored research reports. Vibration, nuclear activation, radiometry, and acoustic detection are among the various techniques employed. (This updated bibliography contains 151 abstracts, 17 of which are new entries to the previous edition.)]]></description>
      <pubDate>Tue, 22 Jul 1980 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/155537</guid>
    </item>
    <item>
      <title>LONG-LIFE TREATMENT FOR AILING M6</title>
      <link>https://trid.trb.org/View/148275</link>
      <description><![CDATA[The necessary reconstruction of 6.5 km of Midlands Link Motorway including two lengths on viaduct and one on embankment is described in this short article.  The sequence of operations is described, and the vibratory rolling of both sub base and wearing course to increase the density of materials is noted.  On the embankment section, because of water penetration problems, hot rolled asphalt is to replace the original lean concrete base.  A Troxler nuclear gauge is in use to achieve accurate and quick density readings for soil, and pavement layers.  Failed joints on viaduct are being replaced by cementitious epoxy plus steel fibres bridge joints.]]></description>
      <pubDate>Tue, 22 Apr 1980 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/148275</guid>
    </item>
    <item>
      <title>OBSERVATION OF AN EXPANSIVE CLAY UNDER CONTROLLED CONDITIONS</title>
      <link>https://trid.trb.org/View/143086</link>
      <description><![CDATA[Observation of the behavior of a highly expansive clay, heavily fissured by dessication, has been made over extended periods.  Measurements were made of soil heave under sustained ponding as a function of time and depth and thus the effects of progressive absorption of water into the clay were directly observed.  Moisture content and density were monitored by nuclear probes.  Attempts to employ double-junction Spanner-type psychrometers were generally unsuccessful in field observations of changes in soil suction although future use for research purposes in less highly fissured soils remains a possibility.  With adequate calibration, the nuclear equipment was found to be quite successful in monitoring changes in moisture content and density.  The simple and inexpensive heave measurements points, pushed or driven into position, are recommended for regular use in observing movements in highway embankments and foundation soils.  The records are believed to furnish a unique set of data because of swell measurements throughout the depth of the affected soil.  Although the tests were not primarily intended for evaluation of pre-swelling by ponding, they show that, in the type of clay tested, the effects of one or two months of ponding are primarily limited to wetting, and stabilizing, only the top five feet. Such an effect may be quite beneficial, but the continued movement of deeper layers must also be expected. /FHWA/]]></description>
      <pubDate>Mon, 31 Mar 1980 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/143086</guid>
    </item>
    <item>
      <title>NUCLEAR MEASUREMENT OF SUBGRADE MOISTURE</title>
      <link>https://trid.trb.org/View/28528</link>
      <description><![CDATA[In this investigation it was proposed to establish a technique for measuring subgrade moisture under pavements with sufficient accuracy, and minimal effort, interference with traffic, and recalibrations.  Both electrical resistance and nuclear methods were investigated.  The following conclusions were reached: (1) the nuclear depth probe method of measuring subgrade moisture is more reliable and easier to use than is the electric resistance method, it does not require precalibration and a general calibration curve for a given probe design could be developed for Virginia; (2) the use of a split sampler for a 2 inch (50 mm) diameter access tube gives a snug fit between the outside wall of the access tube and the surrounding soil, and thus eliminates possible errors in measurement due to an air gap, and it also gives a semi- undisturbed sample of the subgrade soil which is needed for calibration; (3) the access tube could be driven in all types of soils through which the split sampler could pass, without becoming bent; (4) this investigation satisfactorily resolved the methods of sealing the access tube from the top and bottom and removing moisture from the access tube before testing; and (5) the standard error of estimate in the use of a nuclear calibration curve for moisture content could be reduced by using the dry density and soil sieve analysis data.]]></description>
      <pubDate>Wed, 05 Nov 1975 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/28528</guid>
    </item>
    <item>
      <title>CASE STUDIES OF VARIATIONS IN SUBGRADE MOISTURE AND TEMPERATURE UNDER ROAD PAVEMENTS IN VIRGINIA</title>
      <link>https://trid.trb.org/View/33932</link>
      <description><![CDATA[Changes in moisture under uncovered ground and in the subgrades of pavements were evaluated.  The pavements ranged from new to about 10 years old.  Moisture content was determined by a nuclear probe to determine moisture depth.  The findings were as follows: (a) the higher the compaction and dry density of the subgrade soil were, the lower the moisture content would be; (b) subgrade moisture content increased sharply from the beginning to the end of construction; (c) for 1 or 2 years from the date of the subgrade construction, moisture content increased because of precipitation and after this time the rate of increase in moisture decreased; and (d) after about 10 years, there was little increase in the subgrade moisture content.]]></description>
      <pubDate>Wed, 05 Nov 1975 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/33932</guid>
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