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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>
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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>Performance Assessment of Warm Mix Asphalt (WMA) Pavements</title>
      <link>https://trid.trb.org/View/907626</link>
      <description><![CDATA[Warm Mix Asphalt (WMA) is a new technology that was introduced in Europe in 1995. WMA offers several advantages over conventional asphalt concrete mixtures, including: reduced energy consumption, reduced emissions, improved or more uniform binder coating of aggregate which should reduce mix surface aging, and extended construction season in temperate climates. Three WMA techniques, Aspha-min, Sasobit, and Evotherm, were used to reduce the viscosity of the asphalt binder at certain temperatures and to dry and fully coat the aggregates at a lower production temperature than conventional hot mix asphalt. The reduction in mixing and compaction temperatures of asphalt mixtures leads to a reduction in both fuel consumption and emissions. This research project had two major components, the outdoor field study on SR541 in Guernsey County and the indoor study in the Accelerated Pavement Load Facility (APLF). Each study included the application of four types of asphalt surface layer, including standard hot mix asphalt as a control and three warm mixes: Evotherm, Aspha-min, and Sasobit. The outdoor study began with testing of the preexisting pavement and subgrade, the results of which indicated that while the pavement and subgrade were not uniform, there were no significant problems or variations that would be expected to lead to differences in performance of the planned test sections. During construction, the outdoor study included collection of emissions samples at the plant and on the construction site as well as thermal readings from the site. Afterwards, the outdoor study included the periodic collection and laboratory analysis of core samples and visual inspections of the road. Roughness (IRI) measurements were made shortly after construction and after a year of service. The indoor study involved the construction of four lanes of perpetual pavement, each topped with one of the test mixes. The lanes were further divided into northern and southern halves, with the northern halves having a full 16 in (40 cm) perpetual pavement, and with the southern halves with thicknesses decreasing in 1 in. (2.5 cm) increments by reducing the intermediate layer. The dense graded aggregate base was increased to compensate for the change in pavement thickness. The southern half of each lane was instrumented to measure temperature, subgrade pressure, deflection relative to top of subgrade and to a point 5 ft (1.5 m) down, and longitudinal and transverse strains at the base of the fatigue resistance layer (FRL). The APLF had the temperature set to 40°F (4.4°C), 70°F (21.1°C), and 104°F (40°C), in that order. At each temperature, rolling wheel loads of 6000 lb (26.7 kN), 9000 lb (40 kN), and 12,000 lb (53.4 kN) were applied at lateral shifts of 3 in. (76 mm), 1 in. (25 mm), -4 in. (-102 mm), and -9 in. (- 229 mm) and the response measured. Then each plane was subjected to 10,000 passes of the rolling wheel load of 9000 lb (40 kN) at about 5 mph (8 km/h). Profiles were measured after 100, 300, 1000, 3000, and 10,000 passes with a profilometer to assess consolidation of each surface. After the 10,000 passes of the rolling wheel load were completed, a second set of measurements was made under rolling wheel loads of 6000 lb (26.7 kN), 9000 lb (40 kN), and 12,000 lb (53.4 kN) at the same lateral shifts as before. Additionally, the response of the pavement instrumentation was recorded during drops of a Falling Weight Deflectometer (FWD).]]></description>
      <pubDate>Mon, 28 Dec 2009 16:05:05 GMT</pubDate>
      <guid>https://trid.trb.org/View/907626</guid>
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    <item>
      <title>Suitability of Runway Pavement Roughness Indices in Capturing Aircraft Response</title>
      <link>https://trid.trb.org/View/880729</link>
      <description><![CDATA[This paper presents an analysis of the interaction between aircraft responses and runway pavement roughness.  It utilizes the ProFAA software for computing runway pavement statistics and the aircraft simulation model APRas© to simulate the dynamic response of a B737 aircraft. The conventional roughnes indices considered include the International Roughens Index (IRI), the Ride Number (RN), the Profile Index (PI), the Straightedge (SE) index the Boeing Bump Index (BBI) and the Root Mean Square Band-Pass (RMS BP) filter.  In addition, the Normalized Energy (NE) of the pavement profile was computed as an alternative pavement roughness indicator.  The aircraft responses considered included the Center of Gravity Acceleration (CGA), the Pilot Station Acceleration (PSA), the Nose Gear Pavement Loading (NGPL) and the main Gear Pavement Loading (MGPL).  The analysis was carried out through the wavelet approach and summarized in terms of their NE values.  Pearson correlation coefficients were developed between runway roughness statics and aircraft response statistics.  The conventional pavement roughness statistics, with the exception of the PI and the profile roughness NE, were shown unsuitable to describe overall and peak aircraft responses over the full length of runway pavements analyzed. Over shorter runway lengths, such as the 250 m sub-sections analyzed, the profile NE seemed best suited to describe overall aircraft responses, while the IRI seemed best suited to describe peak aircraft responses.]]></description>
      <pubDate>Mon, 30 Mar 2009 13:36:13 GMT</pubDate>
      <guid>https://trid.trb.org/View/880729</guid>
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    <item>
      <title>Evaluation of Slab Shape Under Controlled Environmental Conditions</title>
      <link>https://trid.trb.org/View/758747</link>
      <description><![CDATA[During the curing of Portland cement concrete (PCC) pavements, temperature and moisture gradients in the concrete cause pavement slabs to deform from their initial as-placed shape.  Daily and seasonal environmental cycling can then cause the slabs to expand and contract horizontally with changes in average temperature and moisture conditions, and curl and warp vertically as temperature and moisture gradients change through the slab depth.  This article reports on a study that evaluated slab shape under controlled environmental conditions.  In the study, two 3.66 m (12 ft) wide, by 13.72 m (45 ft) long, by 254 mm (10 in) thick concrete pavements were constructed in the Ohio Accelerated Pavement Loading Facility (APLF). Transverse contraction joints were placed at 4.57 m (15 ft) intervals to create three contiguous 4.57 m (15 ft) long slabs in each pavement. Dowel bars were added to the joints in one pavement, and the other pavement was left undoweled. Results demonstrated large upward vertical deformations along the slab edges early in the curing cycle, and these deformations continued to increase throughout the duration of the tests. The slightly smaller vertical movements observed in the doweled pavement were attributed to the presence of the dowel bars.  The authors conclude that by restraining joint movement, dowel bars transferred load to adjacent slabs and reduced slab deformation.  They note that forces in the dowel bars were smaller than expected from reports on previous investigations, particularly during the curing process.  When modeling PCC pavements, loss of support from the base should be considered as dead and live load stresses are generated in cantilevered slabs.]]></description>
      <pubDate>Tue, 23 Aug 2005 11:26:14 GMT</pubDate>
      <guid>https://trid.trb.org/View/758747</guid>
    </item>
    <item>
      <title>IMPROVING RELIABILITY OF PAVEMENT LOADING ESTIMATES WITH PAVEMENT LOADING GUIDE</title>
      <link>https://trid.trb.org/View/729458</link>
      <description><![CDATA[The development of the Long-Term Pavement Performance (LTPP) Pavement Loading Guide (PLG) was initiated to improve the reliability of traffic load estimates for the LTPP sections that do not have measured axle load data.  The PLG contains extensive traffic data obtained from the LTPP database that may constitute the best available source of traffic data at the national level, a user-friendly graphical interface, and guidelines intended to help the user with the development of axle load spectra. Because of these features, the PLG will also facilitate traffic projections for general pavement design and management purposes. The uncertainty associated with estimating annual axle load spectra was quantified by assuming that the measured data do not exist and must be estimated.  The estimated data were obtained by using axle load spectra obtained at similar sites in the same jurisdiction and utilized prototype PLG software.  The difference between the estimated and the measured traffic loads was quantified by expressing axle load spectra in terms of equivalent single-axle loads.  The results show that reasonable traffic load estimates can be obtained by judiciously selecting replacement traffic data.  Although the PLG can reduce uncertainty of traffic forecasts and facilitate traffic forecasting, surrogate data can never replace site-specific data.]]></description>
      <pubDate>Fri, 19 Dec 2003 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/729458</guid>
    </item>
    <item>
      <title>PERFORMANCE OF PLAIN CONCRETE RUNWAY PAVEMENT</title>
      <link>https://trid.trb.org/View/635856</link>
      <description><![CDATA[This paper investigates the causes of poor performance of plain cement concrete pavement, the most common type of construction for airfield pavements.  Plain concrete pavements are generally cost-effective and durable.  The runway at Zia International Airport at Dhaka, Bangladesh, is a plain concrete pavement, which failed rather prematurely.  Thin longitudinal cracks occurred in the slab panels even before the runway was opened to traffic. With the operation of air traffic, cracks in the pavement became wider, fragmenting the slab panels into several pieces.  This paper is aimed at identifying the causes of poor performance of the plain cement concrete runway pavement at Zia International Airport.  A critical review of the various available documents supported by experimental and numerical investigations is presented to unearth the real causes of failure.  It is shown that improper spacing of the longitudinal and transverse joints and existence of high temperature stresses resulted in cracking of the slab even prior to application of any air traffic loading. This was aggravated with the application of aircraft loadings heavier than those anticipated in the design of the runway.]]></description>
      <pubDate>Mon, 14 Sep 1998 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/635856</guid>
    </item>
    <item>
      <title>THE INFLUENCE OF TEST CONDITIONS AND ASPHALT CONCRETE MIX PARAMETERS ON PERMANENT DEFORMATION COEFFICIENTS ALPHA AND MU (WITH DISCUSSION)</title>
      <link>https://trid.trb.org/View/486833</link>
      <description><![CDATA[In order to achieve a reliable estimate of pavement rutting one must consider loading, material and environmental variables. For asphalt concrete the specific properties of the asphalt mixture provide the greatest uncertainty relative to the cause and degree of rutting. While permanent deformation parameters such as alpha and mu have been used in rut depth calculations, limited research has been undertaken to assess the influence of mix parameters (aggregate type and gradation, binder type and content, and compactive effort) on these coefficients. The overall objective of this research was to investigate the influence of load, environment and mix parameters on the permanent deformation behavior of asphalt concrete.]]></description>
      <pubDate>Thu, 04 Jun 1998 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/486833</guid>
    </item>
    <item>
      <title>KENTUCKY'S EXPERIENCE WITH LARGE SIZE AGGREGATE IN BITUMINOUS HOT-MIX (WITH DISCUSSION)</title>
      <link>https://trid.trb.org/View/486821</link>
      <description><![CDATA[This report discusses Kentucky's experience, from the perspective of practicing engineers, with large size aggregate in bituminous hot-mix in an effort to lessen pavement failures under extreme loading conditions. Kentucky considers "large stone aggregate mixtures" to be those containing aggregate having 100 percent passing the 2-inch sieve and a minimum of ten percent retained on the 1-inch sieve.]]></description>
      <pubDate>Wed, 03 Jun 1998 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/486821</guid>
    </item>
    <item>
      <title>SUBGRADE CRITERIA FOR AIRPORT FLEXIBLE PAVEMENT DESIGN</title>
      <link>https://trid.trb.org/View/475973</link>
      <description><![CDATA[Current mechanistic-empirical airport pavement design procedures use Elastic Layer Programs (ELP) to predict pavement responses (deflections, stresses, strains) generated by the gear load. The procedures incorporate subgrade strain criteria for controlling pavement rutting.  WES/CE/FAA and AI vertical compressive strain criteria were developed from ELP analyses of pavement sections per the revised CBR equation.  The limited scope of pavement test sections and performance data required extrapolation of other subgrade, loading and climatic conditions.  The large and varying rutting criteria used to interpret the test section performance data are not consistent with the more rigorous criteria generally associated with high type airport pavements.  A subgrade stress ratio (SSR = repeated deviator stress/soil strength) approach is presented.  The University of Illinois (U of IL) SSR criteria ensure the pavement exhibits "stable" permanent deformation performance. Subgrade rutting is controlled by limiting SSR to acceptable levels, depending on traffic.  The WES/CE/FAA strain criteria expressed in SSR terms are below about 0.4.  These SSRs are very conservative and result in increased pavement thickness. Permissible SSRs for airport subgrades are probably in the range of 0.5 to 0.7.  Load pulse characteristics (stress level and duration) of multiple-wheel gear configurations and stress history effects (subsequent of stress level applications) on subgrade permanent deformation accumulation need to be further considered in implementing the SSR concept.]]></description>
      <pubDate>Fri, 20 Feb 1998 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/475973</guid>
    </item>
    <item>
      <title>GENERAL OUTLOOK OF PAVEMENT AND VEHICLE DYNAMICS. TECHNICAL NOTE</title>
      <link>https://trid.trb.org/View/475458</link>
      <description><![CDATA[The interaction between vehicle and pavement is complex since pavement roughness excites the dynamic forces generated by vehicles, while these dynamic forces simultaneously increase the pavement roughness.  The objective of this technical note is to provide an overview of the results of recent research related to pavement and vehicle dynamics and their interaction and to evaluate their potential use in the design and management of pavements.  Pavement dynamic models are capable of determining stresses, strains, and deflections in various directions when harmonic, pulse, or transient loads are applied.  Vehicle dynamic models simulate the effect of pavement roughness on the inertia of various vehicle components. These models can predict the dynamic forces produced by different axles and wheels of traveling vehicles at different locations along the pavement. Pavement response computed using dynamic models matches field measurements closer than those computed using static models.  The concept of vehicle-pavement interaction can be applied to weigh-in-motion, pavement design and performance, and vehicle regulations.]]></description>
      <pubDate>Wed, 14 Jan 1998 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/475458</guid>
    </item>
    <item>
      <title>RELATIONSHIP BETWEEN PAVEMENT PERFORMANCE AND ROUTINE MAINTENANCE: MIXED LOGIT APPROACH</title>
      <link>https://trid.trb.org/View/474476</link>
      <description><![CDATA[A mixed logit approach was used to investigate the relationship between routine maintenance and pavement performance.  A discrete model was developed to examine how pavement performance levels affect the probability of performing maintenance on pavement sections.  Another continuous model was formulated to investigate the effect of maintenance on the level of pavement performance.  Maintenance was considered a discrete event representing a binary choice of its being performed on a pavement section or not.  Pavement performance levels were represented by roughness numbers.  Other variables included were pavement thickness, pavement loading, and a regional factor. Pavement thickness was assumed to represent initial construction, and traffic loadings were in the form of equivalent single-axle loads.  The regional factor represented the weather and climatic differences between the northern and southern regions.  A two-stage procedure was applied to evaluate the mixed logit approach.  The data from the Interstate highways in Indiana for 1984 to 1985 were used for model estimation.  The mixed logit approach produced much better results than the single-equation method in specifying the models in terms of coefficient signs and their significances.  The results confirmed that pavement roughness was affected by maintenance and that the decision to undertake maintenance was influenced by the expected level of pavement roughness.]]></description>
      <pubDate>Tue, 09 Dec 1997 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/474476</guid>
    </item>
    <item>
      <title>DYNAMIC RESPONSE EVALUATION OF INCLINED PAVEMENTS WITH INTERFACE SHEAR</title>
      <link>https://trid.trb.org/View/576273</link>
      <description><![CDATA[This paper documents the influence of the pavement-tire interface shear stress and vehicle speed on the response of sloping pavements. An efficient 'finite layer' moving load model has been used to predict the pavement strain response in terms of the principal shear strain and longitudinal tensile strain in the AC layer and the vertical compressive strain on top of the subgrade. The study reveals that, since the increase in the speed of the vehicle decreases the pavement-tire interface shear stress and increases the rate of loading, it plays a major role in decreasing the rate of pavement deterioration.]]></description>
      <pubDate>Thu, 21 Aug 1997 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/576273</guid>
    </item>
    <item>
      <title>ROAD DAMAGE DUE TO DYNAMIC TIRE FORCES MEASURED ON A PUBLIC ROAD</title>
      <link>https://trid.trb.org/View/576271</link>
      <description><![CDATA[This paper describes a series of tests conducted on a UK trunk road, in which the dynamic tire forces generated by over 1500 heavy goods vehicles (HGVs) were measured using a load measuring mat containing 144 capacitive strip sensors. The data was used to investigate the relative road damaging potential of the various classes of vehicles, and the degree of spatial repeatability of tire forces present in a typical highway fleet. Approximately half the vehicles tested were found to contribute to a spatially repeatable pattern of pavement loading. On average, air suspended vehicles were found to generate lower dynamic load coefficients than steel suspended vehicles. However, air suspended vehicles also generated higher mean levels of theoretical road damage (aggregate force) than steel suspended vehicles, indicating that the ranking of suspensions depends on the pavement damage criterion used.]]></description>
      <pubDate>Thu, 21 Aug 1997 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/576271</guid>
    </item>
    <item>
      <title>MEASURING DYNAMIC LOADS FOR HEAVY VEHICLE SUSPENSIONS USING A ROAD SIMULATOR</title>
      <link>https://trid.trb.org/View/576262</link>
      <description><![CDATA[Heavy vehicles apply higher than expected loads to road pavements because of dynamic bouncing. Using vehicle-mounted instrumentation and a variety of truck suspensions, TRL has measured these loads on the TRL research track and on public roads. Work is in progress to develop procedures to enable the road-friendliness of suspensions to be assessed. One possibility is to use a servo-hydraulic road simulator, and the validation of a road simulator as a means of measuring dynamic pavement loads is the subject of this paper. Measurements of dynamic loads during runs over road profiles measured on the TRL track showed discrepancies between the loads on the track and on the road simulator. In many cases there appeared to be more roll motion of the vehicle and its axles on the road simulator than on the track.]]></description>
      <pubDate>Thu, 21 Aug 1997 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/576262</guid>
    </item>
    <item>
      <title>THE USE OF CAPACITIVE SENSORS TO ANALYZE THE DYNAMIC EFFECTS OF VEHICLES ON ROAD PAVEMENTS</title>
      <link>https://trid.trb.org/View/576256</link>
      <description><![CDATA[To analyze the dynamic behavior of vehicles on road pavement, two types of capacitive sensors are examined: one capacitive mat with inductive loops and two capacitive bars with inductive loops, both 'surface-mounted', i.e., installed on top of the road surface. The effects of speed and unevenness are demonstrated for a given vehicle. The effect of vehicle loading is demonstrated at a given speed. Using a known artificial obstacle (bump) placed at a varying distance from the sensors, it has been possible to determine the suspension characteristics of the vehicle.]]></description>
      <pubDate>Wed, 20 Aug 1997 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/576256</guid>
    </item>
    <item>
      <title>PREDICTING HGV ROAD LOADS FROM RIG TESTS WITH INPUTS ON ONE AXLE AT A TIME</title>
      <link>https://trid.trb.org/View/576253</link>
      <description><![CDATA[This paper describes an investigation into the possibility of predicting HGV road (pavement) loads at any speed on a road of known spectral density by measuring the transfer functions relating them to individual axle inputs. The transfer functions of an air-suspension bogie and a rubber walking-beam one were measured on a two-station electro-hydraulic rig, using a variety of input profiles. Two levels of input were used in order to assess nonlinearity effects. Predictions using the transfer functions were compared with existing measurements taken on instrumented vehicles on a test track. The results are sufficiently promising for the method to merit further investigation.]]></description>
      <pubDate>Wed, 20 Aug 1997 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/576253</guid>
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