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Research Report Abstracts

Overlay Design Procedure Volume II

Development of an Improved Overlay Design Procedure for Oregon Volume II

This report is the second in a three-volume series dealing with the development of an improved overlay design procedure for Oregon.  This report presents the results of the second year findings.  Data from five projects were collected and analyzed using both NDT methods 1 and 2 from the 1986 AASHTO Guides.  The overlay thickness using the AASHTO procedure were compared with those using the Caltrans and Oregon DOT methods. 
 
Though the results indicate there are reasonable comparisons between the various methods, the authors have concluded that: 
 

  1. NDT method 1 still needs further work, particularly in developing reliable back calculation methods.
  2. NDT method 2 can be used now with reasonable confidence.

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Overlay Design Procedure Volume III

Development of an Improved Overlay Procedure for Oregon Volume III
This report is the third in a three-volume series dealing with the development of an improved overlay design procedure for Oregon.  This report presents technical guidelines for using the proposed overlay design procedure.
 
Four areas are described, including preliminary work for an overlay design, deflection data analysis methods, overlay design procedures for four types of pavement combination (AC/AC, AC/PCC, PCC/AC, and PCC/PCC) and a guideline for the use of the design procedure.
 
Detailed descriptions of AASHTO NDT method 1 and method 2 have been included.  Three computer programs necessary to implement the NDT method 1 are described.  Computerized approach for the NDT method 2 has been developed.  Examples of overlay design using the proposed procedure are also provided.


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Quick Dry Asphalt Paving Seal

Evaluation of Quick-Dry Asphalt Paving Seal (QDAPS)
Quick-Dry Asphalt Paving Seal (QDAPS) manufactured for Texas.  Refinery Corp. Fort Worth, Texas.  According to the manufacturer, the primary use for this product is "a moisture resistant preventative maintenance asphalt coating for coating and sealing and protecting black-top surface." A secondary use is to penetrate and rejuvenate existing pavements that may have aged excessively due to lack of compaction.  The manufacturer's suggested application rate is 1-1 ½ gallons per 100 square feet.  This will provide 12.03 mil. thickness dry coverage.


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CCRL Concrete Reference

Analysis of CCRL Concrete Reference Sample to Determine Strength Differences Caused by Mold Type

The Oregon State Highway division has conducted several research studies to determine the nature and extent of differences in Portland cement concrete strength caused by types of cylinder mold materials, consolidation, curing, transportation, and testing.  To date, the most significant finding has been the consistent difference found between the compressive strength of cylinders cast in steel, plastic, and tin molds.  The difference ranges from 5%--25%, with steel-molded cylinder being higher in strength than either plastic-molded or tin molded cylinders.  The average difference is from 6%--10%.  These differences have been confirmed for a number of different concrete classes and sources of materials.  No cause for this difference has yet been determined, although several potential causes were evaluated and disproved.  It is not known if this difference is unique to Oregon materials and test procedures, or it is prevalent throughout the United States.  The purpose of this study is to determine the extent of this problem by examining data collected by the Cement and Concrete Reference Laboratory (CCRL), National Bureau of Standards, in their routine concrete reference sample testing program.


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High-Strength Concrete

Morse Brothers, Inc. Harrisburg Plant - High-Strength Concrete Research Study
This report is the seventh in a series of research studies designed to determine the difference in strength of concrete cylinders cast in steel molds vs. cylinders cast in plastic molds. Prior to this report, six other studies on the difference in compressive strength of Portland cement concrete cylinders cast in steel and plastic molds were conducted by the Oregon State Highway Division (OSRD) Materials Section. The purpose of these reports was to determine the quantity of strength difference for different classes of concrete from different suppliers, as well as the possible cause of the strength difference such as mold flexibility, method of vibration, method of transport, curing conditions, etc.  The results of these six studies m summarized in Concrete Cylinder Mold Investigation Summary Report, Oregon State Highway Division Materials Section, March 12, 1987.
This research study was designed to determine which mold (steel, plastic, or tin) produces concrete strength that is most representative of actual strength in a concrete slab structure as determined from concrete cores and tin molds embedded in the slab.  In addition, further comparison of the strength difference in mold type and method of field curing were made.


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DMSO Aggregate Degradation Test

Applicability of the DMSO (Dimethyl Sulfoxide) Aggregate Degradation Test to Determine Moisture Induced Distress in Asphalt Concrete Mixes 
ODOT employs the dimethyl Sulfoxide accelerated weathering test (DMSO test) to identify the potential for degradation of aggregates under high-moisture environmental conditions. A laboratory investigation was conducted to evaluate the effectiveness of the DMSO test to predict moisture-induced distress in asphalt concrete mixtures. Asphalt concrete specimens were fabricated using aggregates from three quarries. The specimens were conditioned using vacuum saturation and a series of five freeze/thaw cycles. The resilient modulus (Mr) was obtained before and after each conditioning cycle and the Index of Retained resilient modulus (IRMr) was determined. The results indicate the DMSO test may be used to identify the potential for moisture-induced distress in asphalt concrete mixtures. However, no correlation was determined between the DMSO test results and the IRMr or fatigue lift test results.
 
The strain and temperature dependencies of the Mr were determined for a dense-graded asphalt concrete mixture.  It was concluded that constant stress testing may result in a misinterpretation of the IRMr, and further, tests conducted within the currently accepted temperature range may result in a (give or take) 20% deviation in the IRMr.  In an accompanying analytical program, the effect of diametral test boundary conditions on the measured value of Mr was evaluated using two- and three-dimensional finite element models.  The results indicate that the resilient modulus diametral test is adequately represented by elastic theory and an assumed plane stress condition.
 
 
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Air Content Study

Portland Cement Concrete Air Content Study
This study was undertaken to review current Oregon State Highway Division specifications, other state specifications, and other available literature to determine:
 

  1. If changes to current specified air content levels should be recommended,
  2. If adjustments to specified air content levels should be made for certain geographic or climatological areas, and
  3. If a price reduction should be assessed against concrete with low air content, and if so, how much.

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Concrete Cylinder 1987

Concrete Cylinder Mold Investigation
In 1985, Oregon State Highway Division (OSHD) began using single use plastic cylinder molds in the field and in pre-stress yards for acceptance testing.  Before this time, field inspectors had been using steel, paper, and tin molds, while the pre-stress yards had been using re-usable steel cylinder molds.  A major reason for changing to plastic molds was that the tin and steel molds were producing cylinders that were out of round and not in compliance with specifications.
 
By the end of the 1985 construction season, one of the pre-stress yards challenged the compressive strength test results of the cylinders cast in plastic molds.  The pre-stress yard felt that the plastic molds produced lower compressive strengths than the steel molds.  In December 1985, the OSHD Materials Section began a research study to determine the cause for the observed differences in strengths of cylinders cast by the pre-stress yard vs. cylinders cast by OSHD inspectors.  Several factors affecting strength were considered, including types of molds, method of curing, method of transporting, flexibility of molds, and thermal conductivity of molds.  The major emphasis of the research was to be on the difference in the compressive strengths between cylinders cast in the plastic molds and steel molds.


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Thin Surface Treatments Interim Report #1

Evaluation of Performance and Cost-Effectiveness of Thin Surface Treatment Interim Report #1
The Oregon Department of Transportation (ODOT) has increased their use of open-graded paving mixtures.  During the last five years, ODOT has constructed several hundred miles of highways with open-graded "F" asphalt concrete mixtures. These pavements have performed well, with no known failures attributable to moisture damage.
 
In 1992, many "F" mixtures failed the Index of Retained Strength (IRS) test used by ODOT to evaluate the water damage potential of asphalt concrete mixtures.  Although "F" mixtures had difficulty passing the IRS test, ODOT engineers felt that the problem was not with the "F" mixtures, but with the test itself.
 
This study investigated the suitability of implementing the Strategic Highway Research Program's (SHRP) Environmental Conditioning System (ECS) procedure for evaluating the water sensitivity of "F" mixtures.  As a part of this study, test data was collected using the IRS test and the ECS test for several different "F" mixtures.  The IRS procedure is more severe that the ECS, indicating potential pavement failure problems where they don't exist and that are not predicted by the ECS. The IRS test may not be suitable for "F" mixtures. The ECS procedure shows promise as a test method for evaluating water sensitivity of "F" mixtures, but further evaluation and correlation with field performance is required.


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Cold In-Place Recycled Volume1

Development of Improved Mix Design and Construction Procedures for Cold In-Place Recycled Pavements Volume 1
This is the first of a three-volume report prepared to document the results of the cold in-place recycling (CIR) effort in Oregon.  The overall objectives of the project are to develop improved design and construction procedures for cold recycles pavements.  Volume I of this report describes the efforts to accomplish this objective over the period 1984-86.  Specific guidelines are given for design, construction, and field control.
 
Volume II contains the supporting data for the research effort.  In particular, it contains a review of selected mix and thickness design procedures, mix design, and field data for the 1986 projects, and the proposed construction specifications for the 1987 projects.
 
Volume III will develop later and will include data documenting the performance of the 1986 projects over a three-year period (1986-89).


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Cold In-Place Recycled Volume 2

Development of Improved Mix Design and Construction Procedures for Cold In-Place Recycled Pavements Volume 2

This is the second of a three-volume report prepared to document the results of the cold in-place recycling (CIR) effort in Oregon.  The overall objectives of the project are to develop improved design and construction procedures for cold recycles pavements.  Volume I of this report describes the efforts to accomplish this objective over the period 1984-86.  Specific guidelines are given for design, construction, and field control.
 
Volume II contains the supporting data for the research effort.  In particular, it contains a review of selected mix and thickness design procedures, mix design, and field data for the 1986 projects, and the proposed construction specifications for the 1987 projects.
 
Volume III will develop later and will include data documenting the performance of the 1986 projects over a three-year period (1986-89).


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Concrete Cylinder Mold - Salem

River Bend, Salem Concrete Cylinder Mold Investigation
OSHD Materials Section has been involved in an on going investigation of differences in compressive strength between plastic and steel cylinder molds.  All prior comparisons have been made using high strength concrete from pre-stress yards.  In this report the comparison is being made using a low strength (4.67 sack 3000 3/4) concrete mix.  The guideline for selecting and preparing cylinder molds will be AASHTO M205-83 (ASTM C470-81).


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Soffit Cathodic Protection Interim Report

Demonstration Project Soffit Cathodic Protection System in a Coastal Environment

This demonstration project evaluates a contractor executed below deck cathodic protection system on two spans of a coastal structure.  The first part of the project evaluated the construction phase and found that the contractor, working under the guidance of a technical representative, very adequately completed the project.  The materials, with the exception of the rectifier, were readily incorporated into the project and resulted in a good operating system.
 
In addition to the contractor implementation of a cathodic protection system, materials and methods are evaluated.  Specifically, design, construction, construction materials for cathodic production systems, evaluation criteria, rectifiers and top of deck behavior are discussed.
 
The ongoing phase of the project is to evaluate the durability of the construction materials and the operating parameters of the system for both protection of the soffit areas and the effect of below deck application on the remote or top of deck area.


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Overlay Design Procedure

Development of an Improved Overlay Design Procedure for Oregon

This report is the first in a three-volume series dealing with the development of an improved overlay design procedure for Oregon. This report presents the results of the first-year findings and includes:
 

  1. a detailed review of the literature
  2. the development of the framework for an improved procedure
  3. an evaluation of data from three projects using several procedures including the proposed AASHTO procedures (NDT methods 1 and 2)
 
The results of this report indicated the following:

  1. The AASHTO procedures have several advantages over the presently used ODOT procedure
  2. The major limitation of the AASHTO procedure is lack of reliable back calculation procedure (NDT method 1)
  3. NDT method 2 appears to work well for low-volume roads and should be tested on high-volume roads

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Oxidative Aging Procedures

Development of Laboratory Oxidative Aging Procedures for Asphalt Cements and Asphalt Mixtures

This paper presents an evaluation of an oxidative aging procedure for asphalt materials.  Test results and the effectiveness of the aging device used are presented.  The study was performed by Oregon State University and the Oregon Department of Transportation.  This study involved laboratory tests on field core samples as well as laboratory mixture samples and asphalt cements used for three projects constructed in Oregon.
 
The procedure selected for aging laboratory mixtures involved using a Pressure Oxidation Bomb (POB), a sealed container in which asphalt mixtures and/or asphalt samples were subjects to pure oxygen at 100 psi pressure at 60 c, for periods of up to 5 days.  Resilient modules and fatigue tests were performed to measure the properties of cores and laboratory mixtures (before and after aging).  The asphalt samples were aged on a Fraass plaque to achieve minimum disturbance of the sample, and the degree of aging was assessed by changes in the Fraass breaking temperature.
 
The results of this study showed that the POB was an effective means of producing measurable changes in both mixtures and asphalt samples.  However, the mixture properties were substantially different from those measured for the field core samples, while the asphalt properties were similar.    As evaluation parameters, the modulus ratio and Fraass breaking temperature are good indicators of aging rate of mixtures and asphalt cement, respectively.  The study also indicated that aging rate is a function of the air voids in the mixture and asphalt properties.


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Polymer Concrete Overlay

Clackamas River Bridge Polymer Concrete Overlay
During the week of August 15, 1983, and experimental methyl methacrylate polymer concrete overlay was placed on a portion of Oregon City’s fifty-two year old Clackamas River Bridge on Highway 99E.  The purpose was to determine the skid number (1) of this thin overlay and observe the wearing characteristics of a Federal Highway Administration (FHWA) formulated polymer concrete.



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Concrete Cylinder Mold 1986

Concrete Cylinder Mold Investigation 1986
Oregon State Highway Department began using plastic single-use concrete cylinder molds as early as 1983 for trial mixes at OSHD using plastic molds for acceptance testing in the summer of 1984, and two additional plants switched to plastic molds in August of 1985.
 
In December of 1985, OSHD Material Laboratory began an investigation into the compressive strength difference between cylinders cast in steel molds versus plastic molds. 


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Standard Accelerated Weather

Development of a Standard Accelerated Weathering Test for Aggregates Using Dimethyl Sulfoxide (DMSO)

A standard accelerated weathering test using Dimethyl Sulfoxide (DMSO) was developed to simulate the chemical degradation of basaltic rocks.  After a thorough study of the parameters affection the current procedure, such as container geometry, aggregate particle size, sample weight, and immersion time, a standard test was developed.  The recommended procedure consists of immersing a sample of aggregate in the size range between 2.38 mm (#8) and 4.76 mm (#4), weighing 1000g, for a period of five (5) days.  At the end of the immersion time the aggregate is re-screened over the 2.38 mm (#8) sieve and the percent weight loss is calculated.  The acceptable weight loss limit for the DMSO Accelerated Weathering Test was established by correlating the test results to those obtained through petrographic analysis.  The petrographic analysis consisted of determining the percentages of deleterious secondary minerals and their textural distribution within the rock matrix.  With these two parameters, a Secondary Mineral Rating for each quarry rock.  A second indirect test, the Clay Index, was presented as a simple method to determine the likelihood of DMSO to overreact, since it was found to be insensitive to the type of minerals present in the rock.


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