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Research Report Abstracts II

Triaxial and Diametral Test

Determination of Resilient Properties of Unbound Materials with Repeated Load Triaxial and Diametral
Repeated load diametral test systems are experiencing increased use to determine resilient properties of asphalt concrete and admixture stabilized materials; they have not been used extensively to determine the resilient properties of unbound materials.  This is due in part to the fact that comparative studies between the properties obtained with the diametral test system and the repeated load triaxal test system have not been made.  In response to the need to establish a correlative data base between resilient properties determined with diametral and repeated load triaxial test systems, a laboratory test program was conducted.  Specifically, resilient properties of two-base course and two subgrade materials were determined using both repeated load triaxial and diametral test systems.  The resilient properties of duplicate specimens (with respect to water content, dry density method of compaction) were compared over the rage of material conditions considered.  The resilient properties determined with either the repeated load diametral or triaxial test systems were approximately equivalent.  The differences between resilient moduli for comparable states of stress were +80%.   Correlations between resilient moduli can only be made for a specific material at a given water content, dry density, and method of general correlation factors between resilient properties determined with diametral or triaxial test systems with those of the conventional R-valve test.  The differences between resilient moduli determined with either the diametral or triaxial test system led to negligible differences in the design thickness of materials in representative pavement structures.


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Warren-Scappoose Asphalt Life

Impact of Variations in Material Properties on Asphalt Pavement Life - Evaluation of Warren-Scappoose

Several changes have occurred in recent years, in the type of highway materials, and in the asphalt paving technology.  New asphalt sources have been brought on line, introducing changes in asphalt properties.  New equipment has also been developed, affecting mixing (dryer drum mixers, more efficient dust collector systems), storage (mix storage silos) and compaction (vibratory compactors).  In the same period, economical constraints have resulted in increasing use of lower quality aggregate.  As a result, there has been an increase in construction or short-term performance problems throughout the Pacific Northwest (1). The impact of such changes on the mix properties is, however, difficult to evaluate. Table 1 summarizes the main changes observed and their expected influence on the mix behavior.
 
A recent project is located on the Columbia River Highway between Warren and Scappoose. The base course was constructed in 1979 and the wearing surface in 1980. Progressive pavement raveling and potholing were noticed in the base course during the months following construction. Evaluation of the reduction in pavement life resulting from the variations in mix and pavement properties (e.g., aggregate quality, gradation, density, asphalt content) resulted in a study of the mix dynamic properties under controlled conditions.  A new approach was used to assess the effects of these mix variables on pavement life.


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Asphalt Life - Castle Rock

Impact of Variation in Material Properties on Asphalt Pavement Life - Evaluation of Castle Rock-Cedar

Construction and short-term pavement performance problems were noted in the Pacific Northwest and throughout the United States during the past five years.  Several reasons have been suggested to explain this sudden change in pavement performance, such as recent variabilities in asphalt properties and new developments in paving technology.  Using the data and construction materials issued from a recent project built in 1979, Oregon State Highway Department and Oregon State University conducted a laboratory study t o determine the relationship between asphalt concrete pavement performance and mix level of compaction, asphalt content, and mix gradation.
 
Conventional tests and improved dynamic tests were run on laboratory compacted samples to determine mix stiffness, fatigue life and permanent deformation characteristics.  Based on fatigue and permanent deformation test results, preliminary pay adjustment factors were developed by comparing performance of mix specimens prepared at the design optimum with the performance of mix out of specifications.  It was found that performance is primarily affected by the mix level of compaction.  Fatigue data corroborated the design optimum asphalt content (6%), and showed a strong interaction between the asphalt content and the amount of fines.  Mix susceptibility to permanent deformation decreased when increasing the amount of fines and decreasing the asphalt content.  A summary table giving the most critical pay adjustment factors between the fatigue and the permanent deformation criteria is developed in the conclusions and recommendations chapter.


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Concrete Overlay Test Final Report

Polymer Concrete Overlay Test Program - Final Report

The results in this report were obtained during the test program which began in 1973.  Physical properties of various polymer concretes are listed.  They include compressive strength, splitting tensile strength, bond strength, the modulus of elasticity, shrinkage and thermal coefficients. A description is also presented of three polymer concrete overlays and one polymer chip seal that were placed on bridge decks.


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Pavement Life - N Oakland

Impact of Variation in Material Properties on Asphalt Pavement Life: Evaluation of N Oakland-Sutherlin Project 
Construction and short-term pavement performance problems were noted in the Pacific Northwest and throughout the United States during the past five years.  Several reasons have been suggested to explain this sudden change in pavement performance, such as recent variabilities in asphalt properties and new developments in paving technology. 
 
Using the data and construction materials from a recent project built in 1978-1979, Oregon Department of Transportation and Oregon State University initiated a laboratory study to determine the relationship between asphalt concrete pavement performance and mix level of compaction, asphalt content, gradation, and aggregate quality.
 
Conventional tests and improved dynamic tests were made on laboratory compacted samples to determine mix stiffness, fatigue life and permanent deformation characteristics.  Based on fatigue and permanent deformation test results, preliminary pay adjustment factors were developed by comparing performance of mix prepared at the design optimum with the performance of mix out of specifications.  It was found that performance was primarily affected by the mix level of compaction. Both the fatigue and permanent deformation tests indicated that an optimum asphalt content and optimum passing the No. 200 (074 mm) exist.  Fatigue data also showed that anti-strip agents are effective when added to the asphalt before mixing with aggregate.  A summary of the most critical pay adjustment factors is developed in the conclusions and recommendations chapter.


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Lebanon Ditch Bridge

Polymer Concrete Overlay of Lebanon Ditch Bridge

On Wednesday, August 26, 1981, a polymer concrete overlay was placed on the Lebanon Ditch Bridge on Highway 16 at milepost 13.56W.  This bridge was selected for the experimental overlay because the deck had exposed and polished aggregate in the wheel tracks which reduced the skid resistant texture and moderate transverse cracking which allowed water to penetrate the concrete.  The bridge was constructed in 1947.


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High Mast Luminaire

Evaluation of High Mast Luminaire Lowering Devices in Oregon
High mast luminaire lowering devices were installed on two projects in Oregon following approval by the Department of Transportation, Federal Highway Administration, of the installations as experimental features projects.  Holophane Company, Inc., supplied 23 units that were installed in the Seventh Avenue - Willamette River Section of 1-105 near Eugene in 1973. Valmont Industries, Inc., furnished 38 units that were installed on the South Tigard Interchange - East Portland Freeway Interchange section of 1-5 south of Portland. The latter installations were made in 1976. Before these lowering devices were specified, high mast illumination was serviced by using a portable elevator. These fixed installations had several disadvantages.  Principal among them was the reluctance of maintenance personnel to ride maintenance cars to the heights involved in servicing high mast lighting. Other disadvantages involved the difficulty of getting the elevator to the pole where access is not convenient and the potential hazard where the public has access to the pole and steps, cables and cabinets.
 


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Pay Adjustment Factors

Evaluation of Questionnaire on Pay Adjustment Factors for Asphalt Concrete Mixtures
In an effort to collect information on the status of quality control procedures and the use of pay adjustment factors, a questionnaire was distributed to all state agencies, the District of Columbia, and the Federal Highway Administration.  Each agency was asked to respond to questions describing their current method for acceptance or rejection of asphalt concrete paving materials and related pay adjustment factors. 
 
This report summarizes the results of the questionnaire. Analyses of results indicate:
 
1) Most state agencies will accept one or more property characteristics of asphalt concrete that are outside specification tolerances.
2) Most state agencies apply a pay adjustment factor to accepted materials which are outside specification tolerances.
3) Only 26 percent of the state agencies consider their pay factors to be proportional to reduced pavement serviceabi1ity.
4) Approximately one-ha1f of the agencies consider the use of pay factor plans as effective in encouraging compliance with specifications.
5) There is a wide disparity in the pay adjustment factors used by the different agencies.
 


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Flexible Glare Shield

Evaluation of Flexible Plastic Glare Shield in Oregon 
 This experimental features project was approved by the Department of Transportation, Federal Highway Administration, on July 11, 1973.  A four-mile section of flexible plastic glare screen was installed on top of the existing concrete median barrier on the Baldock Freeway in September of 1974. This is a six-lane, high-volume section with lineal illumination and a designated speed o f 55 mph. Amber reflectors were installed at the same time.  The purpose of this report is to summarize the data collected when flexible plastic glare screen was installed on the concrete median barrier on the 1-5 Baldock Freeway in Portland, Oregon.


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Materials on Asphalt Question

Impact of Variation in Materials Properties on Asphalt Pavement Life Evaluation of a Questionnaire
In an effort to collect information on the status of quality control procedures and the use of pay adjustment factors, a questionnaire was distributed to all state agencies, the District of Columbia, and the Federal Highway Administration.  Each agency was asked to respond to questions describing their current method for acceptance or rejection of asphalt concrete paving materials and related pay adjustment factors.
 
This report summarizes the results of the questionnaire.  Analyses of results indicate:
 

  1. Most state agencies will accept one or more property characteristics of asphalt concrete that are outside specification tolerances.
  2. Most state agencies apply a pay adjustment factor to accepted materials which are outside specification tolerances.
  3. Only 26 percent of the state agencies consider their pay factors to be proportional to reduced pavement serviceability.
  4. Approximately one-half of the agencies consider the use of pay factor plans as effective in encouraging compliance with specifications.
  5. There is a wide disparity in the pay adjustment factors used by the different agencies.
 
This is the first of several reports to be prepared in connection with this project.


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Overview on Pay Adjustment Factors

An Overview on Pay Adjustment Factors for Asphalt Concrete Mixtures

In the fall of 1979, the Oregon State Highway Division and Oregon State University with participation from the University o f Washington initiated a research project to study the impact of variations in material properties on asphalt pavement life. This study is aimed at developing a rational approach to assess the effects of variations from specification limits so a firm basis can be established for the development of pay factors.
 
In an effort to collect information on the status of quality control procedures and the use of pay adjustment factors, a questionnaire was distributed to all state agencies, the District of Columbia, and the Federal Highway Administration. Each agency was asked to respond to questions describing their current method for acceptance or rejection of asphalt concrete paving materials and related pay adjustment factors.
 
This report summarizes the results o f the questionnaire. Analyses of results indicate:
 

  1. Most state agencies will accept one or more property characteristics of asphalt concrete that are outside specification tolerances.
  2. Most state agencies apply a pay adjustment factor to accepted materials which are outside specification tolerances.
  3. Only 26 percent of the state agencies consider their pay factors to be proportional to reduced pavement serviceability.
  4. Approximately one-half o f the agencies consider the use of pay factor plans as effective in encouraging compliance with specifications.
  5. There is a wide disparity in the pay adjustment factors used by the different agencies.
 


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Pavement Patching

The Evaluation of Pavement Patching Materials in Oregon
This report describes the installation and evaluation of trial pavement patching materials in Oregon. The patches were placed in Portland cement concrete and bituminous concrete pavements and evaluated for periods ranging from four to twelve months.
 
Of the five products used in patching the Portland cement concrete pavement, the epoxy concrete and the acrylic polymer concrete materials were found to have greater durability than the other products tested.  Their costs were considered high at between $1350 t o $1675 per cubic yard.
 
The evaluation of patching materials for bituminous concrete pavements was limited to cold-mixed, cold-applied products. Of the four materials examined, Sta-Fil was rated superior.  Its cost at $450/ton was a major disadvantage.


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Materials in Marine Piling

An Evaluation of Improved Structural Materials in Marine Piling
A study to evaluate the production and field performance of marine piling fabricated with improved structural materials is currently being performed by the Oregon State Highway Division under the sponsorship of the Federal Highway Administration. In this study, materials that were developed mainly for bridge deck protection and rehabilitation were used in fabricating pre-cast pre-stressed concrete piling. During this project, 23 test piles measuring 12" x 12" x 65' long were fabricated and placed in a dolphin for pier protection in Yaquina Bay at Newport, Oregon.
 
The special materials incorporated into the study included polymer concrete, polymer impregnated concrete, latex modified concrete, and internally sealed concrete. Five piles were fabricated using each system. In addition, six miniature piles measuring 8" x 8" x 20' containing epoxy coated reinforcing steel bars were constructed and attached to three conventional pre-cast pre-stressed concrete piles.
 
This project was unique in several ways. It was the first time all four of the experimental materials were tested in a single study and the first time three of the systems were used in a pre-stressed element in the United States.  Because each of the systems had to be modified to some degree, an accelerated laboratory study was conducted to prepare specifications for construction of the piles and their installation. After a six month study, enough data was generated to write specifications and to let a contract. Due to the complexity of the project, only one pre-stressed concrete plant submitted a bid to fabricate the piles. That company was Morse Bros. Pre-stress Inc. of Harrisburg,
Oregon.


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Modified Fibrous Concrete

Latex Modified Fibrous Concrete Sundial - Sandy River Section
In November 1980, the Siuslaw Construction Company requested permission to substitute a 1.5 inch Latex Modified Fibrous Concrete (LMFC) overlay for either a 2.5 inch low slump concrete (Iowa System) or a 2.5 inch un-reinforced latex modified concrete overlay on four bridge decks within the Sundial - Sandy River Section. At that time a presentation was made by OBEC consulting engineers on the benefits of using this new material. The greater flexural strength of the concrete due to the presence of the fiber was the reason cited for reducing the overlay thickness.
 
The request was studied by state highway engineers before conditional approval was granted.  Oregon's problems with cracking in previously placed deck overlays greatly influenced the decision to allow an alternate overlay system.


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Steel Stringer Tops

Membrane Protection for Steel Stringer Tops
The Yaquina Bay Bridge on the Oregon Coast Highway at Newport, Oregon has direct coastal exposure to the Pacific Ocean, which has resulted in serious corrosion problems related to structural and reinforcing steel in the structure. This problem is particularly concentrated in steel members under the deck where salt-laden moisture condenses and is not washed away by the rain. Corrosion of the steel reinforcing bars in the bottom of the concrete deck had caused spalling of the concrete to the extent that the entire deck and sidewalk throughout the three steel arch spans had to be completely replaced. The deck replacement utilized steel grid decking over the existing steel stringers.



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Construction and Short-term

Evaluation of Construction and Short-Term Performance Problems for Asphalt in Oregon
During the three-year period from 1974 to 1977, an increased occurrence of asphalt concrete pavement problems were noted throughout the United States during and after construction. In Oregon, construction and performance problems that were seldom experience prior to 1974 developed, and include:
 
(1) Incompactible mixes,
(2) Slow setting mixes,
(3) Flushing mixes,
(4) Low mix cohesion, and
(5) High incidence of ''blue smoke" during mixing and lay down.
 
In an effort to determine the causes of these problems, questionnaires were sent to regional and field construction engineers in 1975 and 1976 to establish the type and extent of problems and to collect information for each job, such as construction procedures, material properties, and mix designs, which may be related to the observed problems. Based on these results, fourteen projects with and without problems were selected for additional study and evaluation. These evaluations included: 
 
(1) Conducting performance surveys,
(2) Obtaining cores of good and bad sections,
(3) Performing test on the mixes, and
(4) Performing tests on the asphalt.
 
This report summarizes the results of the questionnaire, field survey and laboratory testing. Analysis of the results indicates:
 
(1) Many of the reported problems in Oregon were due to extreme variations in material properties, such as high fines, high asphalt content, and low asphalt viscosity.
(2) Variations in asphalt temperature susceptibility between grade and between suppliers, as well as use of drum dryer type paving plants and in consistent addition of dust collector materials may also have contributed to the observed variations in material properties.
 
The study addresses a significant problem which has been observed throughout the United States. Hopefully, it will indicate to others that many factors can contribute to construction and performance problems and that all factors need to be carefully considered.


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Hot Mix Asphalt Recycling

Evaluation of Oregon's First Hot Mix Asphalt Recycling Project -- Woodburn, Oregon, 1977
Pavement recycling has been suggested as a viable alternative to more conventional methods of pavement rehabilitation as a means of offsetting some of the problems resulting from spiraling energy costs and shortages of raw materials.  This paper presents a discussion of the Woodburn Asphalt Recycling Paving Project, Oregon's first experience at large-scale asphalt concrete recycling utilizing a hot-mix process.  The project is described briefly and overlay and mix designs are indicated. The construction program and specific equipment utilized are reviewed.  The program of material sampling and testing and data collection is described. Test results are summarized. Special emphasis is given to an investigation of possible changes in material properties through the construction process. A summary of those factors most affecting emission production is presented.  Costs and fuel consumption are summarized and possible savings over a similar conventional paving project are highlighted. Specific recommendations are presented to other agencies proposing similar projects. Finally, future research needs are outlined.


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Polymer Concrete Dev. and Use

Polymer Concrete Development and Use in Oregon
Oregon first became interested in polymer concrete in 1973 when the Federal Highway Administration offered to sponsor a polymer concrete overlay in this state. Because of the need to find a durable, quick setting, high early strength concrete for use in overlaying bridge decks in the Portland area, the offer was accepted.
 
The original work plan specified that laboratory tests would be conducted to determine the most suitable resins for overlay work. It must be pointed out that the Oregon State Highway Division was not set up to do polymer research, but only to test existing resin formulations that were readily available from chemical companies.  After a literature search, two generic resins were chosen for study. They were methyl methacrylate and polyester styrene.


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