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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>Sustainable Base Courses</title>
      <link>https://trid.trb.org/View/1428733</link>
      <description><![CDATA[At existing airports, re-aligning and replacing taxiways is a common practice due to reconfigurations of the operational area or just normal wear and tear. For example, with the arrival of the new “Super-Jumbo Jet” aircrafts, such as the Airbus A380, the nation’s taxiways will need widening and increased load capacity to accommodate the large aircrafts. It is common practice when removing and re-aligning taxiways to dispose of the material and replace it with new material, either asphalt or other base courses. The authors wanted to try and reuse some of this material to develop sustainable design, and reduce material costs. Preliminary research in the Port Authority of NY & NJ Materials Laboratory investigated the possibilities of reusing existing asphalt pavement (RAP), lime-cement-flay ash base course (LCF) and blending it with Portland cement to create a sustainable base course. This research was successful and lead to the option of using either a new asphalt base or a blend of existing pavement and Portland cement in a contract to upgrade the taxiways at John F. Kennedy International Airport. The low bidder chose to use recycled pavement materials and blend it with cement on-site. This sustainable option not only proved to be economical but efficient as well. The on-site blending of Portland cement with the removed pavement material saved in travel time and reduced truck traffic on the surrounding infrastructure. This paper will discuss in detail the following topics related to sustainable base courses: Preliminary laboratory results; Sustainable base course mix design; Batching and placement methods; QC/QA procedures; and Test results.]]></description>
      <pubDate>Mon, 21 Nov 2016 13:43:34 GMT</pubDate>
      <guid>https://trid.trb.org/View/1428733</guid>
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    <item>
      <title>Evaluation of Fly Ash in Lean Portland Cement Concrete Base "Econocrete"</title>
      <link>https://trid.trb.org/View/1377631</link>
      <description><![CDATA[Fly ash was used in this evaluation study to replace 30, 50 and 70 percent of the 400 lb. of cement currently used in each cu. yd. of portland cement econocrete base paving mix. Two Class "C" ashes and one Class "F" ash from Iowa approved sources were examined in each mix. When Class "C" ashes were used, they were substituted on the basis of 1.0 lb. for each lb. of cement removed. When Class "F" ash was used, it was substituted on the basis of 1.25 lb. of ash for each lb. of cement removed. Compressive strengths with and without fly ash were determined at 7, 28 and 56 days of age. In most cases, strengths were adequate. The freeze/thaw durability of the econocrete mixes studied was not adversely affected by the presence of fly ash. The tests along with erodibility and absorption tests have demonstrated the feasibility of producing econocrete with satisfactory mechanical properties even when relatively low quality and/or locally available aggregate is being used at no sacrifice to strength and/or durability.]]></description>
      <pubDate>Thu, 17 Dec 2015 16:49:10 GMT</pubDate>
      <guid>https://trid.trb.org/View/1377631</guid>
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    <item>
      <title>Thirty-Year Performance Evaluation of Two-Layer Concrete Pavement System</title>
      <link>https://trid.trb.org/View/1091972</link>
      <description><![CDATA[In 1978, an experimental two-layer concrete pavement was opened to traffic on SR-45 near Fort Myers, Florida. The experimental pavement included a series of two-layer concrete pavement sections with various design features placed over either a granular or a cement-treated subbase. These sections consisted of a 3-in. (7.5-cm) portland cement concrete (PCC) surface over a 9-in. (23-cm) lean concrete (commonly referred to as econocrete) layer. The control section consisted of a standard PCC 9 in. (23 cm) thick with joints spaced at 20 ft (6 m) on a cement-treated subbase. After 30 years of service, the sections constructed over a granular base performed better than those placed over a cement-treated subbase. The distresses on the two-layer concrete pavement sections built on the granular subbase were minimal, regardless of their slab lengths. In contrast, the control section experienced greater cracking, greater corner deflections, and moderate-to-severe spalling. The findings validate several features of Florida’s current design policies, such as limiting joint spacing to 15 ft and prohibiting cement-treated subbases directly below concrete pavements. Furthermore, this project has demonstrated that a two-layer concrete system consisting of a relatively thin high-quality PCC surface over a lower-quality econocrete layer and a granular subbase can be a sustainable and long-lasting pavement design alternative.]]></description>
      <pubDate>Mon, 21 Mar 2011 14:13:32 GMT</pubDate>
      <guid>https://trid.trb.org/View/1091972</guid>
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    <item>
      <title>PERMEABLE CONCRETE ECO-PAVING AS BEST MANAGEMENT PRACTICE IN AUSTRALIAN URBAN ROAD ENGINEERING</title>
      <link>https://trid.trb.org/View/665052</link>
      <description><![CDATA[Research into the structural and hydraulic properties of permeable concrete segmental eco-paving has been active in Australia for almost 10 years. Moreover, over the last six years a significant number of projects in Australia have successfully utilized this new form of construction. This paper describes the progress that has been made in the testing, evaluation, design and construction of permeable eco-paving is summarized and critically assessed and a state-of-the-art review is presented. The role and potential of permeable concrete segmental paving in best management practice in Australian urban road engineering is then assessed. This is illustrated by a series of case histories.]]></description>
      <pubDate>Fri, 03 Oct 2003 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/665052</guid>
    </item>
    <item>
      <title>ECONOCRETE IN PAVEMENT DESIGN</title>
      <link>https://trid.trb.org/View/717636</link>
      <description><![CDATA[In many areas of the U.S., the supply of conventional aggregates meeting present specifications is rapidly being depleteed or has already become exhausted. This shortage is partly due to overly restrictive specifications and to a lack of technology and development to utilize those aggregates in a concrete pavement system. With the necessary advances in research and development, previously rejected aggregate sources could furnish a substantial amount of the aggregates needed in pavement construction in some parts of the U.S. With this in mind, the American Concrete Paving Association's Technical Subcommittee on Materials and Mix Design started work in 1973 on the development of a composite concrete pavement structure. The aim was to produce a high quality, skid resistant, durable concrete surfacing on top of a concrete designed for local environmental conditions and made from locally available commercial materials. The term Econocrete was coined to describe the concrete mixtures developed under this program, and this paper focuses on the uses of Econocrete as a composite, subbase, shoulder, and paving material in pavement structures.]]></description>
      <pubDate>Tue, 26 Feb 2002 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/717636</guid>
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      <title>PORTLAND CEMENT CONCRETE UTILIZING RECYCLED PAVEMENTS</title>
      <link>https://trid.trb.org/View/717635</link>
      <description><![CDATA[During 1974 and 1975, the state of Iowa became interested in and began investigations into uses of "Econocrete." That is, the use of locally available materials, or lower quality materials, in base course pavement construction. Further discussions resulted in consideration of recycling an existing portland cement concrete roadway. This paper describes a site where this concept was attempted on a 1.6-mile stretch of a road project in the northwest corner of Iowa. The project was an attempt to remove and crush the existing pavement, use the material as it came from the crusher, hopefully without further processing, perhaps add some concrete sand, and to proportion, mix, place, and finish with conventional slip form paving equipment. The mix design used, an overall discussion of the project, and observations and recommendations are all provided.]]></description>
      <pubDate>Mon, 25 Feb 2002 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/717635</guid>
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    <item>
      <title>RESPONSE OF CONCRETE HIGHWAY PAVEMENTS WITH ECONOCRETE BASES. FINAL REPORT</title>
      <link>https://trid.trb.org/View/356647</link>
      <description><![CDATA[Two computer programs for stress and deflection analysis of concrete highway pavements, FEACONS for plate bending analysis considering a liquid subgrade, thermal curling and joint stiffness, and INPLANE for analysis under in-plane shrinkage, temperature and joint effects, were modified to handle skewed transverse joints.  A series of calculations using FEACONS, under wheel loading and temperature, were performed to study the effect of subgrade stiffness levels and joint stiffness levels on the distribution of stresses in the pavement.  Results were presented as profiles of principal stress and deflection magnitudes.  A number of laboratory pilot tests were performed on plain unreinforced beams to study the fatigue resistance in flexure of Florida concrete.]]></description>
      <pubDate>Mon, 30 Sep 1996 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/356647</guid>
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    <item>
      <title>DEVELOPMENT OF ACCEPTANCE PLANS FOR AIRPORT PAVEMENT MATERIALS. VOLUME I -- DEVELOPMENT. FINAL REPORT</title>
      <link>https://trid.trb.org/View/344143</link>
      <description><![CDATA[The objective of this research is to develop statistically based acceptance/rejection plans and payment adjustment schedules for five specifications covered under the Federal Aviation Administration's Advisory Circular No. 150/5370/10, Standards for Specifying the Construction of Airports, namely:  P-152, Excavation and Embankment; P-209, Crushed Aggregate Base Course; P-304, Cement Treated Base Course; P-306, Econocrete Subbase Course; and P-501, Portland Cement Concrete Pavement.  This report includes the statistical analysis of data, development of payment adjustment plans (PAP), and development of PAP computer diskette system. Test data used for this effort were collected from field sources.  The developed PAP formulas, schedules, and computer diskette system were verified using new pavement construction projects.  This report is divided into two volumes with Volume I, Development, describing the development of PAP, and Volume II, Computer Operator's Manual, describing the operation details of the PAP diskette system.]]></description>
      <pubDate>Wed, 31 Oct 1990 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/344143</guid>
    </item>
    <item>
      <title>FLORIDA ECONOCRETE TEST ROAD: A 10-YEAR PROGRESS REPORT. PROCEEDINGS, 4TH INTERNATIONAL CONFERENCE ON CONCRETE PAVEMENT DESIGN AND REHABILITATION, PURDUE UNIVERSITY, APRIL 18-20, 1989</title>
      <link>https://trid.trb.org/View/303039</link>
      <description><![CDATA[The Florida Econocrete Test Road was designed and constructed in response to the energy crisis of the 1970's. In addition to using econocrete bases with 3-in. concrete pavements, several experimental features were included. Among those were the principle of elastic joints applied to the pavement-base interface, the CRCP, and to specially designed dowels.  Thin unbonded reinforced pavements were also included.  Common variables were joint spacings of 15 ft. and 20 ft., and skewed as well as transverse joints. The 10 year performance study was based on structural response in load-deflection tests and performance rating using the Mays Meter.  All concrete sections were compared to a standard concrete pavement section as then built by the Florida Department of Transportation.  The experimental sections generally performed equivalent or better than the concrete reference section.  The study also included asphalt pavements placed on econocrete base structures.  These sections were compared to an asphalt reference section as presently built by the Department.  Again, the experimental sections fared well when compared to the reference section.]]></description>
      <pubDate>Thu, 31 Aug 1989 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/303039</guid>
    </item>
    <item>
      <title>PERFORMANCE OF CONCRETE PAVEMENT WITH ECONOCRETE BASE. PROCEEDINGS, 4TH INTERNATIONAL CONFERENCE ON CONCRETE PAVEMENT DESIGN AND REHABILITATION, PURDUE UNIVERSITY, APRIL 18-20, 1989</title>
      <link>https://trid.trb.org/View/303050</link>
      <description><![CDATA[A three-lane, 16 mile section of I-85 in Randolph and Davidson Counties, North Carolina, was opened to traffic in 1984.  The spring following the opening of this section of highway, reddish-brown stains were visible on the concrete shoulders.  Water was determined to be flowing under the slabs and blowing out through weak points along the joints. The data collected in an attempt to understand this phenomenon included:  horizontal and vertical movements of the slabs, static and dynamic pavement deflections, temperature gradients of the pavement system, location of dowels in the slabs, concrete and soil material properties, and field observations to identify water movement.  Possible causes of the problems were identified and methods to minimize damage to the pavement were recommended as a result of this study.]]></description>
      <pubDate>Thu, 31 Aug 1989 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/303050</guid>
    </item>
    <item>
      <title>FIELD EVALUATION OF CLASS A SUBBASE USING FLY ASH. FINAL REPORT</title>
      <link>https://trid.trb.org/View/287026</link>
      <description><![CDATA[This project consisted of slipforming a 4-inch thick econocrete subbase on a 6-mile section of US 63.  The project location extends south from one mile south of Denver, Iowa to Black Hawk County Road C-66 and consisted of the reconstruction and new construction of a divided four-lane facility.  The econocrete was placed 27.3 feet wide in a single pass.  Fly ash was used in this field study to replace 30, 45 and 60 percent of the portland cement in three portland cement econocrete base paving mixes.  The three mixes contained 300, 350 and 400 pounds of cementitious material per cubic yard.  Two Class "C" ashes from Iowa approved sources were used.  The ash was substituted on the basis of one pound of ash for each pound of cement removed.  The work was done October 6-29, 1987 and May 25-June 9, 1988.  The twelve subbase mixes were placed in sections 2500 to 3000 feet in length on both the north and southbound roadways.  Compressive strengths of all mixes were determined at 3 and 28 days of age.  Flexural strengths of all mixes were determined at 7 and 14 days.  In all cases strengths were adequate.  The freeze/thaw durability of the econocrete mixes used was reduced by increased fly ash levels but remained above acceptable limits.  The test results demonstrate the feasibility of producing econocrete with satisfactory properties even using fly ash at substitution rates up to 45 percent.]]></description>
      <pubDate>Sat, 31 Dec 1988 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/287026</guid>
    </item>
    <item>
      <title>MICHIGAN MEN TAKE LEAD AT AIRPORT NEEDS CONFO</title>
      <link>https://trid.trb.org/View/289733</link>
      <description><![CDATA[This article briefly summarizes a seminar held in Orlando, Florida, which had the theme "Building to Meet Future Needs."  The seminar was sponsored by the American Concrete Pavement Association and the Portland Cement Association, in cooperation with the Federal Aviation Administration and the Greater Orlando Aviation Authority.  Richard Bonner, Chief Engineer, Orlando Airport Authority, welcomed the group and discussed the development program for the Orlando International Airport.  The paving project underway at the present time is a third runway with apron pavement for a new terminal building under contract.  Robert Blancheau, Greiner, Inc., project engineer for the third runway project, discussed the pavement construction for the Orlando Airport.  The project is being built by Denton Construction Company.  Sam Carman, Project Manager, discussed the paving operations, pointing out that this is a major project, which involves 530,000 sq yd of econocrete base course and 462,000 sq yd of 17-in. PCC pavement.  The seminar included a bus tour to observe the pavement construction operations.  Of added interest was the use of a new CMI 550 slipform paver with dowel bar inserter to implant dowels in the plastic concrete for the transverse contraction joints.  L.E. Denton, Denton Construction Co., discussed the effects of design and specifications on construction costs.  He emphasized the need for uniformity in pavement widths and standardized joint design, because those factors influence pavement cost as well as performance.  Other discussion topics at the seminar included pavement needs and proposed construction program for military airfields, design of general aviation airports, quality control in airport paving projects, airport pavement rehabilitation, innovative technology in concrete pavement construction, design and construction of concrete pavements and overlays to meet the needs of future traffic, and reconstruction and recycling airport pavements.]]></description>
      <pubDate>Wed, 30 Nov 1988 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/289733</guid>
    </item>
    <item>
      <title>EVALUATION OF PORTLAND CEMENT CONCRETE SHOULDERS IN GEORGIA. FINAL REPORT</title>
      <link>https://trid.trb.org/View/281725</link>
      <description><![CDATA[This study, conducted by the Georgia Department of Transportation's Research Bureau, evaluated doweled Portland Cement Concrete (PCC) pavement projects with tied PCC shoulders with reference to design, and compared their load transfer performance against undoweled and doweled PCC pavement projects with asphalt shoulders.  To evaluate PCC pavement performance, PCC pavement projects with asphalt shoulders, tied PCC shoulders, and varying bases were compared.  Figure 5 in the Results section illustrates the progress of PCC pavement performance with changes in base design, addition of dowels in the main line pavement, and exchange of asphalt shoulders for tied PCC shoulders. According to data acquired for this report, the best main line pavement performance was achieved by using asphalt concrete mix design H and/or econocrete for a base material, dowels in the pavement and tied PCC shoulders.  Other benefits of tied PCC shoulders include:  1) structural support to the PCC pavement, 2) distribute loads from PCC pavement, 3) reduce flexural stresses and strains in the extreme outside fibers of the PCC pavement, 4) reduce deflections at PCC pavement edge, 5) when used in conjunction with a joint sealer, decrease surface water infiltration at the longitudinal shoulder joint, reduce base, subbase, subgrade saturation and erosion, and reduce voids, faulting and general pavement deterioration, and 6) reduce shoulder settling and deterioration from repetitive truck loadings by truck encroachment.]]></description>
      <pubDate>Sun, 31 Jul 1988 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/281725</guid>
    </item>
    <item>
      <title>HIGH FLYASH CONCRETE IN PAVEMENTS</title>
      <link>https://trid.trb.org/View/198385</link>
      <description><![CDATA[The increased forecast production of flyash, future pressures of resource utilization and protection of environment will compel the greater utilization of flyash. Recently, high flyash concrete (hfc) has emerged as a material of construction in its own right.  It is proposed that substantial quantities of flyash can be utilized in subbase and/ or base of a pavement structure as rolled concrete or econocrete.  Some potential applications of hfc are reviewed and some recent applications of hfc on the local scene are listed.  A laboratory study is described of hfc mixes using Alberta flyash (air entrained and non-air entrained) of medium to low workability for placement by slip forming and roller compaction, respectively.  The concretes were characterized as to their compressive, indirect tension and flexural strengths, drying shrinkage and freeze-thaw durability.  It is confirmed that cohesive non-segregating concrete can be manufactured containing up to 75 per cent flyash in the cementitious fraction.  These mixes can be effectively air entrained which in turn provides adequate freeze-thaw durability.  The tensile and compressive strength achieved are adequate for the proposed applications.  In particular, the high tensile/ comprehensive strength ratio is most attractive in pavement applications.  (TRRL)]]></description>
      <pubDate>Mon, 30 Apr 1984 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/198385</guid>
    </item>
    <item>
      <title>ANALYSIS OF PAVEMENT STRUCTURES USING DYNAFLECT DEFLECTIONS</title>
      <link>https://trid.trb.org/View/194645</link>
      <description><![CDATA[During the construction of a rigid pavement test road, a series of plate bearing tests were performed to evaluate subgrade support values.  Laboratory and field tests were performed to determine moduli and other properties of the econocrete and high quality concrete paving materials.  PCC and econocrete composite modulus values were transformed into an equivalent modulus.  The dynaflect testing device was used to measure deflection basins at different locations within each section of the completed pavement.  Elastic and liquid subgrade stiffnesses, consistent with the measured deflected basins, were determined using continuous models developed by Hogg and by Westergaard, respectively.  These implied stiffnesses were used to identify an appropriate way to interpret the plate bearing tests performed on each test section.  Plate bearing stiffness values were interpreted from the test data so that they would be compatible to the liquid subgrade stiffness values needed as input into a finite element pavement model.  (Author/TRRL)]]></description>
      <pubDate>Tue, 30 Aug 1983 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/194645</guid>
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