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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>
    <image>
      <title>Transport Research International Documentation (TRID)</title>
      <url>https://trid.trb.org/Images/PageHeader-wTitle.jpg</url>
      <link>https://trid.trb.org/</link>
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    <item>
      <title>RESEARCH ON VIBRATORY MAXIMUM DENSITY TEST FOR COHESIONLESS SOILS</title>
      <link>https://trid.trb.org/View/119516</link>
      <description><![CDATA[THE USE OF RELATIVE DENSITY AS A METHOD OF CONTROL FOR COMPACTION OF COHESIONLESS SOILS IS HAMPERED BY LACK OF AN ADEQUATE METHOD FOR DETERMINING THE MAXIMUM SOIL DENSITY. PREVIOUS INVESTIGATIONS HAVE SHOWN THAT HIGHER DENSITIES ARE OBTAINED FOR MOST COHESIONLESS SOILS BY VIBRATORY METHODS THAN PRESENTED BY THE STANDARD IMPACT COMPACTION METHODS. THE RESULTS ARE PRESENTED OF AN INVESTIGATION OF VIBRATORY METHODS TO DETERMINE THE COMBINATION OF VARIABLES WHICH WOULD GIVE THE HIGHEST DENSITY. FOUR ELECTROMAGNETIC TABLE-TYPE VIBRATORS, AN IMMERSION-TYPE CONCRETE VIBRATOR, AND A PNEUMATIC TABLE-TYPE VIBRATOR WERE USED IN THIS INVESTIGATION. THE EFFECT ON THE SOIL DENSITY OF MAGNITUDE OF SURCHARGE, TIME OF VIBRATION, AMPLITUDE OF VIBRATION, AND WATER CONTENT WERE STUDIED FOR SEVEN COHESIONLESS SOILS REPRESENTING A WIDE RANGE IN GRADATIONS. A SUMMARY OF THE BUREAU OF RECLAMATIONS TEST PROCEDURE FOR DETERMINING THE RELATIVE DENSITY OF COHESIONLESS SOILS USING A VIBRATORY TABLE IS INCLUDED. FOR THE RANGE OF AMPLITUDES INVESTIGATED, MAXIMUM DENSITIES WERE GENERALLY OBTAINED AT THE HIGHER AMPLITUDES. ADDITIONAL RESEARCH IS NEEDED TO DETERMINE THE OPTIMUM DEADWEIGHT SURCHARGE. THE INCREASE IN DENSITY WAS INSIGNIFICANT FOR TIMES OF VIBRATION GREATER THAN 6 MIN, AND 8 MIN SEEMS TO BE A REASONABLE AND SUFFICIENT TIME FOR THE EQUIPMENT AND SOILS TESTED. THE INITIAL DENSITY OF THE SOIL PRIOR TO VIBRATION DID NOT HAVE A SIGNIFICANT EFFECT ON THE FINAL DENSITY. THE DIFFERENCE BETWEEN THE DENSITIES OBTAINED USING OVEN-DRIED SOIL AND INITIALLY SATURATED SOIL WAS NOT SIGNIFICANT FOR MOST OF THE SOILS TESTED. DISCUSSIONS ARE APPENDED. THE PAPER WAS PRESENTED AT THE 67TH ANNUAL MEETING OF THE SOCIETY. /RRL/A/]]></description>
      <pubDate>Sun, 15 Aug 2004 02:22:57 GMT</pubDate>
      <guid>https://trid.trb.org/View/119516</guid>
    </item>
    <item>
      <title>CONCRETE VIBRATION, SEGREGATION, AND SUSCEPTIBILITY TO SEGREGATION /IN FRENCH/</title>
      <link>https://trid.trb.org/View/97086</link>
      <description><![CDATA[PROBLEMS ENCOUNTERED DURING THE VIBRATION OF CONCRETE, ESPECIALLY THE COMPACTION OF CONCRETE USED FOR CONTROL SAMPLES ARE DISCUSSED. A LARGE NUMBER OF TESTS WERE CARRIED OUT IN CONJUCTION WITH THE AFNOR COMMITTEE. RESULTS LED TO THE ESTABLISHMENT OF AN EXPERIMENTAL RULE FOR CALCULATING SAMPLE VIBRATION TIME. BY EXTRAPOLATION, THIS RULE WAS ADAPTED TO NORMAL VIBRATION TIME FOR CONCRETE STRUCTURES. NOMOGRAPHS ARE PRESENTED FOR EACH TYPE OF SAMPLE, ON WHICH WILL BE BASES THE SPECIFICATION NFP 18 422 "PLACING OF CONCRETE BY MEANS OF A VIBRATING NEEDLE." THE SECOND PART IS CONCERNED WITH SEGREGATION AND SUSCEPTIBILITY TO SEGREGATION. A SEGREGATION INDEX FOR MEASURING CONCRETE SEGREGATION ENABLES THE EXPERIMENTAL STUDY OF SEGREGATIONS TO BE CONDUCTED AS A FUNCTION OF MIX- DESIGN, WATER PROPORTIONING, MIXING, TRANSPORT, VIBRATION, ETC. DETAILS ARE GIVEN OF AN APPARATUS DEVELOPED FOR TESTING CONCRETE BY MEASURING ITS SEGREGATION UNDER STANDARDIZED AND REPETITIVE CONDITIONS. /LCPC(A)RRL/]]></description>
      <pubDate>Thu, 29 Jul 2004 17:52:42 GMT</pubDate>
      <guid>https://trid.trb.org/View/97086</guid>
    </item>
    <item>
      <title>BRITISH SYSTEM FOR SLIP-FORMING CONCRETE PAVEMENTS</title>
      <link>https://trid.trb.org/View/102659</link>
      <description><![CDATA[THE SLIP-FORM PAVER DESCRIBED IN THIS ARTICLE IS OF UNUSUAL INTEREST IN TWO ASPECTS OF ITS DESIGN. THE FIRST IS ITS PURPOSE SINCE IT IS INTENDED FOR THE CONSTRUCTION OF MINOR ROADS, SUCH AS LOCAL STREETS FOR SUBDIVISIONS, AS OPPOSED TO MOTORWAYS. RELATIVELY SHORT LENGTHS OF PAVEMENT CAN BE CONVENIENTLY CONSTRUCTED. SLABS ABOUT 12 FT IN WIDTH ARE LAID BY THE NEW PAVING MACHINE. THE SECOND ASPECT OF INTEREST LIES IN THE THEORETICAL BACKGROUND OF ITS DESIGN. A NEW APPROACH TO THE WAY IN WHICH FRESH CONCRETE FLOWS UNDER THE INFLUENCE OF VIBRATION HAS HAD A DECISIVE INFLUENCE ON THE DESIGN OF THIS MACHINE. THE RESULT IS THAT THE KIND OF CONCRETE THAT IS NEEDED FOR SLABS - HARSH MIXES OF POOR WORKABILITY - CAN BE LAID AND COMPACTED BY THE PAVER AT ACCEPTABLE RATES OF PROGRESS. /AUTHOR/]]></description>
      <pubDate>Thu, 28 Apr 1994 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/102659</guid>
    </item>
    <item>
      <title>VIBRATORS RUN ON FEW SIMPLE RULES</title>
      <link>https://trid.trb.org/View/107448</link>
      <description><![CDATA[THE LIFE OF HEAVY-DUTY CONCRETE VIBRATORS IS PROLONGED BY SIMPLE MAINTENANCE. THEY SHOULD BE CLEANED, HUNG UP AFTER USE AND PROPER VOLTAGE SHOULD BE MAINTAINED ON THE JOB. HARDENED CONCRETE OR SOLID OBJECTS SHOULD BE AVOIDED. THE VIBRATOR IS DESIGNED TO OPERATE ON FRESHLY POURED, FAIRLY LIQUID CONCRETE WHICH HAS A COOLING EFFECT AND PREVENTS OVERHEATING. WORN PARTS, SUCH AS THE FLEX AND THE FLEX DRIVE, MUST BE PROMPTLY REPLACED. /CGRA/]]></description>
      <pubDate>Thu, 24 Feb 1994 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/107448</guid>
    </item>
    <item>
      <title>INVESTIGATIONS OF INTERNAL VIBRATION OF CONCRETE</title>
      <link>https://trid.trb.org/View/95415</link>
      <description><![CDATA[A TESTING METHOD HAS BEEN DEVISED FOR DETERMINING THE RADIUS OF ACTION OF INTERNAL VIBRATORS IN FRESH CONCRETE. TESTS HAVE BEEN MADE WITH INTERNAL VIBRATORS WITH VARYING FREQUENCIES, AMPLITUDES, TUBE DIAMETERS, ETC. THE LARGEST RADIUS OF ACTION WAS OBTAINED AT AN OPTIMUM FREQUENCY ABOUT 12000 VIBR.PER MIN. THE RADIUS OF ACTION OF AN INTERNAL VIBRATOR WAS TO A HIGH DEGREE INFLUENCED BY THE CONSISTENCE AND THE COMPOSITION OF THE CONCRETE, THE DIMENSION AND DESIGN OF THE FORM, AND THE REINFORCEMENT. A NUMBER OF TEST SPECIMENS WERE COMPACTED WITH INTERNAL VIBRATORS, WORKING WITH DIFFERENT FREQUENCIES AND AMPLITUDES. AFTER HARDENING 15 CM CUBES WERE SAWED FROM THE TEST SPECIMENS. THE VARIATIONS IN THE COMPRESSIVE STRENGTH AND IN THE UNIT WEIGHT OF THE CUBES WERE FOUND TO BE SMALL. /RRL/A/]]></description>
      <pubDate>Sun, 20 Feb 1994 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/95415</guid>
    </item>
    <item>
      <title>A STUDY OF UNIT WEIGHT, VOLUME AND CEMENT FACTOR OF FRESH CONCRETE</title>
      <link>https://trid.trb.org/View/98395</link>
      <description><![CDATA[TESTS WERE MADE IN THE LABORATORY AND IN THE FIELD TO SHOW THE EFFECT OF VARIOUS METHODS OF COMPACTION ON UNIT WEIGHT, YIELD AND CEMENT FACTOR OF FRESH CONCRETE. THE FOLLOWING CONCLUSIONS ARE BASED ON THE FINDINGS OF TESTS USING VARIOUS CONCRETE MIXES, COMPACTION EFFORTS, AND FIELD SAMPLES: (1) LARGE INCREASES IN THE AMOUNT OF VIBRATION OF CONCRETE IN THE UNIT WEIGHT TEST PRODUCED VERY SMALL CHANGES IN THE ACTUAL UNIT WEIGHT. REVIBRATION OF JOB CONCRETE FOR 20 SECONDS WITH AN INTERNAL VIBRATOR FOLLOWING STANDARD RODDING (WHICH WOULD FAR EXCEED NORMAL JOB VIBRATION) PRODUCED AN INCREASE IN UNIT WEIGHT OF APPROXIMATELY 0.3 PERCENT. (2) THE VIBRATION IN UNIT WEIGHT AND CALCULATED CEMENT FACTOR AS DETERMINED FROM THE UNIT WEIGHT TEST TAKEN IN FRONT OF AND BEHIND A PAVING MACHINE IS VERY MINOR. ON THE TWO PROJECTS TESTED, THE UNIT WEIGHT WAS FOUND TO AVERAGE 0.5 PERCENT AND 0.4 PERCENT GREATER WHEN SAMPLED BEHIND THE PAVING MACHINE. (3) THE LONG-ESTABLISHED SYSTEM OF USING THE UNIT WEIGHT TEST TO DETERMINE YIELD AND CEMENT FACTOR OF CONCRETE DELIVERED TO THE JOB IS MORE ACCURATE THAN ANY OTHER SYSTEM. /BPR/]]></description>
      <pubDate>Sat, 08 Jan 1994 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/98395</guid>
    </item>
    <item>
      <title>ACI MANUAL OF CONCRETE PRACTICE 1990. PART 2. CONSTRUCTION PRACTICES AND INSPECTION PAVEMENTS. BEHAVIOR OF FRESH CONCRETE DURING VIBRATION</title>
      <link>https://trid.trb.org/View/348425</link>
      <description><![CDATA[This report covers the state-of-the-art processes that take place in the consolidation of fresh concrete during vibration.  These processes, rheologicl and mechanical in nature, are discussed to provide better understanding of the principles.  The first chapter presents the historical developments relative to consolidating concrete.  The second chapter deals with the rheological behavior of concrete during consolidation and the associated mechanisms of dynamic compaction.  The third chapter presents the principles of vibratory motion occurring during vibration, vibratory methods, and experimental test results. Continuing research in the field of concrete vibration, as evidenced by the extensive literature devoted to the subject, is addressed.]]></description>
      <pubDate>Thu, 31 Jan 1991 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/348425</guid>
    </item>
    <item>
      <title>VIBRATION OF CONCRETE</title>
      <link>https://trid.trb.org/View/187102</link>
      <description><![CDATA[Optimum compaction of concrete must be achieved if the concrete is going to achieve its strength and durability requirements.  This article discusses the compaction process, tracing the early techniques and reporting on todays's equipment.  The historical background is briefly reviewed, together with the relationship between vibration and compaction.  Characteristics of fresh concrete such as compactability, mobility and stability are outlined and a discussion of vibration mechanisms is presented.  Aspects of vibration and vibrators are discussed under the following headings: types of vibrators, internal vibrators, flexible shaft poker vibrators, pneumatic poker vibrators, external vibrators, vibrating screeds, table vibration, internal vibrators, poker sizes and applications (tabulated data), length of head, using a poker vibrator (detailed guidelines), length of time required for full compaction, revibration and care and maintenance of poker vibrators. External or clamp-on vibrators are dealt with in rather less detail.  It is pointed out that though modern day methods of mechanical vibration provide the economic means of compacting concrete in most construction situations, they cannot make up for human deficiencies in the handling of equipment which usually relates to having insufficient manpower and equipment available to match the speed of concrete placing that can be achieved.  (TRRL)]]></description>
      <pubDate>Mon, 28 Feb 1983 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/187102</guid>
    </item>
    <item>
      <title>UNDERWATER CONCRETING. EXPERIENCES IN THE FIELD</title>
      <link>https://trid.trb.org/View/153181</link>
      <description><![CDATA[The Swedish National Road Administration has followed up the underwater concreting of 46 foundation slabs for bridge piers.  In 35 cases the concrete was pumped directly into concreting pipes, in 11 cases into open funnels on the top of conventional tremie pipes.  In 8 cases the concreteing failed and extensive reinforcement of the foundation slabs became necessary.  Failures were most frequent in the first concreted slabs, but even later on about 10% of the slabs failed.  The main cause of failures was poor consistency and flowing-ability of the concrete.  Often the concreting pipes were badly controlled and became drawn up too much, when poor consistency resulted in high values of the pumping pressure.  Reinforcement bars also sometimes led to failures when the concrete was pumped at a high velocity around them. Good results were obtained with special pumping-equipment (rigid arm link with damping spring, air-driven valve in the bottom of the concreting tube, end-pipe of at least - 5" and end-cone of - 8", pumping capcity strangled to about 1/3 at starting and at critical points) and with good concrete consistency (slump 15-17 cm at the mixing station). Vibrating of underwater concrete seems to be possible and increases the concrete strength.  The mean strength of 178 drilled cores was 33,7 mpa, standard deviation 7,7 mpa, and of 96 standard cubes 46,8 mpa, standard deviation 5,3 mpa. This indicates a loss in strength of about 15 mpa caused by the concreting method. (TRRL)]]></description>
      <pubDate>Tue, 22 Jul 1980 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/153181</guid>
    </item>
    <item>
      <title>VIBRATION IN THE MANUFACTURE OF CONCRETE PRODUCTS</title>
      <link>https://trid.trb.org/View/75901</link>
      <description><![CDATA[Utilisation of vibration for the fabrication of concrete products is very widespread.  A good knowledge of vibration and associated phenomena is necessary to avoid numerous undesirable effects during vibration.  This study provides useful information for the understanding of vibration phenomena and the method of action of vibration on concrete. It also gives indispensable guidelines for the design of vibration equipment.  These guidelines include the choice of vibrator, suspension systems and restraint systems.  Finally the methods of control and measurement of vibration characteristics transmitted to the concrete are examined. /TRRL/]]></description>
      <pubDate>Sun, 03 Dec 1978 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/75901</guid>
    </item>
    <item>
      <title>ENGINE INDUCTION DEVELOPMENTS - ECONOMIC AND REDUCED EXHAUST EMISSIONS: FUEL VAPOURIZATION-ECONOMY WITH REDUCED EXHAUST EMISSION</title>
      <link>https://trid.trb.org/View/53377</link>
      <description><![CDATA[This paper describes a simple system of controlling exhaust emissions from gasoline engined vehicles, using A coolant-heated fuel vaporiser in the inlet system.  The object of complete vaporisation of the fuel is to create A homogeneous inlet charge, giving improved cylinder-to-cylinder distribution and permitting operation with very lean mixtures.  This leads to low exhaust emissions of carbon monoxide, hydrocarbons and nitric oxides.  The effects of vaporisation on the lean limit of operation, exhaust emissions, power output, fuel consumption and optimum spark ignition timing have been investigated, and are discussed in the paper.  Results of tests on A 1.6 litre car are also presented.  It was found that exhaust emissions were effectively controlled, while vehicle driveability remained acceptable.  Engine power was reduced by 25 - 30%, although fuel consumption was not increased. /TRRL/]]></description>
      <pubDate>Thu, 13 Oct 1977 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/53377</guid>
    </item>
    <item>
      <title>POST-TENSIONING PLUS SPECIAL VIBRATION SYSTEM AIDS PRODUCTION OF GIANT PRECAST PRESTRESSED GIRDERS</title>
      <link>https://trid.trb.org/View/109500</link>
      <description><![CDATA[THE REPORT DESCRIBES THE PRODUCTION OF GIANT PRECAST, PRESTRESSED CONCRETE, BRIDGE GIRDERS.  THE HEAVILY REINFORCED SECTIONS HAD TO BE CAST ON A RELATIVELY TIGHT TIME SCHEDULE.  TO CONSOLIDATE THE CONCRETE, SPECIAL EXTERNAL VIBRATORS WERE DEVELOPED WHICH WERE PERMANENTLY MOUNTED TO THE FORMS.  THE VIBRATORS ARE ATTACHED TO THE CHANNELS WELDED TO BOTH SIDES OF THE FORMS BETWEEN THE GUSSETS ON ALTERNATING 60- OR 80-IN. CENTERS MOUNTED HIGH AND LOW.  A SPECIAL BRACKET USED TO MOUNT THE VIBRATORS AFFORDED FAST REMOVAL FOR EASY TRANSFER FROM FORM TO FORM. DETAILS ARE GIVEN OF THE HUGE ANCHOR-CANTILEVER GIRDERS AND ILLUSTRATIVE FIGURES ARE PRESENTED.  THE CASTING METHOD FOR THESE MEMBERS WAS TO PLACE THE CONCRETE IN FIVE OR SIX LIFTS, FILLING FROM THE CENTER TO THE ENDS OF THE FORM. EACH BEAM REQUIRED APPROXIMATELY 30 CU YDS OF CONCRETE AND SIX VIBRATORS WERE OPERATED SIMULTANEOUSLY TO CONSOLIDATE THE MIX.  ONE INTERNAL VIBRATOR WAS REQUIRED TO SATISFY STATE SPECIFICATION.  A FEATURE OF THE CONSTRUCTION WAS THE FIELD SPLICE BETWEEN THE 90 FT, 47-TON ANCHOR GIRDER AND THE 82-FT 6-IN., 58-TON ANCHOR-CANTILEVER GIRDER.  THESE SECTIONS WERE POST-TENSIONED ON A BARGE BEFORE ERECTION. EXTERNAL VIBRATORS MOUNTED ON THE STEEL FORM WERE USED TO CONSOLIDATE THE CONNECTING DIAPHAGM CONCRETE.  THE 120-FT DROP-IN GIRDERS WERE PLACED BETWEEN THE DAPPED ENDS OF THE TWO ERECTED CANTILEVERS AND THEIR CONNECTING DIAPHRAGM WAS MADE.]]></description>
      <pubDate>Wed, 19 Jun 1974 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/109500</guid>
    </item>
    <item>
      <title>CONTINUOUSLY REINFORCED CONCRETE PAVEMENTS IN MISSISSIPPI</title>
      <link>https://trid.trb.org/View/96388</link>
      <description><![CDATA[THIS REPORT COVERS A FIVE YEAR OBSERVATION STUDY OF CONTINUOUSLY-REINFORCED CONCRETE PAVEMENT CONSTRUCTION IN MISSISSIPPI.  MEASUREMENTS FROM THE DESOTO COUNTY AND JONES COUNTY EXPERIMENTAL PROJECTS CONSTRUCTED IN 1961 AND 1962 WERE CONTINUED.  THE BACKGROUND HISTORY OF THE TWO PROJECTS IS REVIEWED BRIEFLY AND THEIR DESIGN FEATURES, DATA ON END MOVEMENT, CRACK WIDTH AND CRACK FREQUENCY ARE PRESENTED AND DISCUSSED.  MISSISSIPPI'S CURRENT DESIGN AND CONSTRUCTION PRACTICE FOR CRCP WERE REVIEWED AND SPECIAL ITEMS SUCH AS SPLICES, TRANSVERSE REINFORCEMENT, TERMINAL TREATMENTS, END CONSTRUCTION ARRANGEMENT, VIBRATION OF CONCRETE, CURING OF CONCRETE AND LONGITUDINAL CENTER JOINT ARE DISCUSSED.  FIELD MEASUREMENTS ON PRESENT SERVICEABILITY INDEX, CRACK SPACING AND DEFLECTION ARE INCLUDED AND EVALUATED.  ALSO INCLUDED IN THE REPORT IS A PROPOSED MAINTENANCE PROCEDURE FOR CRC PAVEMENTS.  /NTIS/]]></description>
      <pubDate>Sat, 23 Mar 1974 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/96388</guid>
    </item>
    <item>
      <title>INVESTIGATION OF VIBRATORY METHOD OF FINISHING CONCRETE PAVEMENT IN ILLINOIS</title>
      <link>https://trid.trb.org/View/102728</link>
      <description><![CDATA[THIS INVESTIGATION WAS CONDUCTED TO STUDY THE PRACTICABILITY OF THE VIBRATORY METHOD OF PLACING CONCRETE ON A REGULAR PAVING CONTRACT. MIXTURES OF STANDARD PROPORTIONS PLACED BY CONVENTIONAL METHODS WERE COMPARED WITH TWO TYPES OF MIXTURES PLACED BY VIBRATION, IN WHICH THE PROPORTION OF FINE TO COARSE AGGREGATE WAS ADJUSTED TO GIVE THE BEST RESULTS. BOTH GRAVEL AND CRUSHED STONE COARSE AGGREGATES WERE USED. IN ONE TYPE MIXTURE, DESIGNED FOR STANDARD YIELD, A REDUCTION IN MIXING WATER OF ABOUT ONE- HALF GALLON PER BAG OF CEMENT AND A CORRESPONDING INCREASE IN STRENGTH WERE OBTAINED. IN THE OTHER, IN WHICH THE STANDARD WATER-CEMENT RATIO WAS MAINTAINED, A SAVING IN CEMENT OF ABOUT 10 PER CENT WAS OBTAINED WITHOUT REDUCTION IN STRENGTH. THE PROGRESS OF THE WORK WAS AS SATISFACTORY AS WITH THE CONVENTIONAL METHODS AND THE SURFACE OF THE PAVEMENT SHOWED NO DEFECTS AFTER ONE YEAR. THE RELATIVE AMOUNTS OF HONEYCOMB IN THE SLABS SHOWED THAT THE VIBRATORY METHOD IS FAR SUPERIOR TO THE ILLINOIS STANDARD METHOD IN CONSOLIDATING THE CONCRETE. CONCRETE OF ONE INCH SLUMP, WHICH WAS ABOUT AS DRY AS COULD BE DISCHARGED AND SPREAD BY THE MIXER BUCKET, WAS CONSOLIDATED VERY SATISFACTORILY AROUND TRANSVERSE METAL JOINTS, WHEN INSTALLATION BARS TO PROTECT THE COPPER SEAL OR BITUMINOUS CAP WERE USED. /AUTHOR/]]></description>
      <pubDate>Mon, 23 Aug 1971 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/102728</guid>
    </item>
    <item>
      <title>METHODS OF VIBRATION OF CONCRETE ACCORDING TO FRENCH PRACTICE</title>
      <link>https://trid.trb.org/View/102724</link>
      <description><![CDATA[FRENCH PRACTICE WENT IN FOR HEAVY VIBRATING OR TAMPING OF PAVEMENT CONCRETE. BRIEF DESCRIPTIONS OF SEVERAL MACHINES WERE GIVEN, SOME OF WHICH RAN ON SIDE RAILS AND OTHERS RESTED DIRECTLY UPON THE FRESH CONCTETE. A FEATURE OF THE PRACTICE WAS A BRUSHING MACHINE FOR ROUGHENING THE SURFACE TO MAKE IT SKID PROOF BY REMOVING THE FINE MATERIAL DURING THE SETTING AND HARDENING PERIOD. ONE BELIEF WAS IN USING LEAN MIXTURES WITH ENOUGH VIBRATION OR RAMMING TO FORCE THE INDIVIDUAL PIECES OF LARGE SIZE AGGREGATE INTO SUCH INTIMATE POSITIONS THAT WERE SECURELY BONDED TO EACH OTHER BY A MINIMUM AMOUNT OF CEMENT. ALMOST NO CRACKING AND LITTLE WEAR WAS OBSERVABLE ON TEN YEAR OLD PAVEMENTS, IN THE HEART OF PARIS, LAID BY THESE METHODS. /AUTHOR/]]></description>
      <pubDate>Sun, 15 Aug 1971 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/102724</guid>
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