| Abstract XXI |
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| Shale Embankment |
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Evaluation of Shale Embankment Construction Criteria
A 1.5 mile section of the Coos Bay-Roseburg Highway in Oregon was reconstructed in 1983. The project was located in an area where degradable fine-grained siltstone and sandstone would be encountered in the through cuts. After the construction of the adjacent Slater-Mystic Creek section in 1974, it was recognized that significant settlement and stability problems were developing as a result of the use of these degradable rocks in the construction of embankments. The Oregon Department of Transportation (ODOT) completed a demonstration study described herein to evaluate the use of these materials for embankments and riprap revetment at nine structures.
The study concluded that use of visual classification, aided by slake durability testing, was reliable in the selection of rock-like materials for use in slope revetments. Where rock was determined to be nondurable, it was physically broken down and placed and compacted as soil. The performance of the embankments in the five years following construction has been very good and no appreciable settlement is evident. The rock placed as revetment has performed as anticipated, with about 25 percent of the material degrading. This is attributable to limitations in sorting the durable and nondurable material during excavation. As a result of this demonstration study, ODOT has implemented a practical and effective embankment specification for selection and treatment of degradable rock materials in highway construction.
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| METRO RUMAC |
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Rubber Modified Asphalt Concrete (METRO RUMAC) Evaluation
This report covers the construction in 1992 of test sections on two projects using asphalt concrete modified with tire rubber. One project's test sections are part of a single lift overlay on a lightly traveled two-lane road south of Klamath Falls, Oregon. The other project's test sections are part of the base course of a three-lift overlay on a heavily traveled four-lane divided highway between Eugene and Springfield.
All test sections use a dense-graded rubber modified asphalt concrete developed for the METRO agency of the Portland, Oregon urban area (METRO RUMAC). Control sections were paved with conventional asphalt concrete adjacent to the test sections. The test sections are compared to these control sections.
The METRO RUMAC was successfully blended for both projects by adding unopened bags of the rubber to the pugmill of the mix supplier's batch plants. The rubberized mixes could be placed and compacted by conventional equipment. One project's test sections could not be rolled to the desired density. An improper mix gradation may have prevented compaction. The other project's test sections could be compacted to the desired density. Immediately after compaction, construction traffic traveled on one project's hot METRO RUMAC pavement, and the vehicle's tires adhered to and damaged the surface.
Experience on these projects indicate that the specification limits for crumb rubber need to be revised, and in some cases, the percentage of rubber required in the METRO RUMAC needs to be lowered to obtain satisfactory mix properties. In addition, solvent extractions were successfully used on one project to determine the overall gradation of the METRO RUMAC.
Sampling and testing methods were developed to see if the crumb rubber added to these pavements met the MEIT0 RUMAC specifications.
After construction, both project's METRO RUMAC and conventional pavement sections had similar appearances and surface friction values. On one project, the test and control section's ride quality was compared, and the METRO RUMAC and conventional mixes had similar characteristics.
The METRO RUMAC mixes cost 1.3 to 2.0 times as much as their conventional counterparts. Much of this cost was due to the addition of the rubber, and the extra asphalt required by the rubberized mixes.
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| Corbett-Swarbrick Procedure |
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Experiences in Implementing the Corbett-Swarbrick Procedure for Separation of Asphalt into Four Gene
This paper presents an evaluation of the Corbett-Swarbrick procedure for separation of asphalt into four generic fractions. The Corbett-Swatbrick procedure, currently accepted as an ASTM standard (ASTM D4124-82) has been submitted for revision to the ASTM committee. The revised procedure involves considerable modifications to the existing standard.
Oregon State University together with Oregon State Highway division have implemented both procedures (current RSTM standard and the revised procedure) and used them on a routine basis in an ongoing research program. The implementation of both procedures created a number of difficulties. Most of these difficulties were related to the interpretation of the standard and the lack of more complete information associated with the severa1 steps to follow when performing the entire test.
The purpose of the paper is to present the major difficulties encountered with the implementation of the test and present some recommendations for future revisions of the current standard. Several aspects of the test procedure are analyzed, such as: the method used for asphaltene prescription, filtration, solvent concentration and some
Problems related to the use of alumina and the chromatographic column.
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| Travel Time Estimation |
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Dynamic Travel Time Estimation Using Regression Trees
The report presents a methodology for travel time estimation by using regression trees. The dissemination of travel time information has become crucial for effective traffic management, especially under congested road conditions. In the absence of collected actual observations on travel time, the vehicle speed can be predicted by using regression trees, which in turn is used as a proxy to estimate the travel time. To maintain stable prediction ability in both free flow conditions and near-capacity flow conditions on freeways, the regression tree model developed for this study includes thirteen explanatory variables, categorized in four variable types: traffic flow, incident related, weather data, and time of day. A total of four characterization standards (outliers, weather, incidents, and weekday/weekend) are used to characterize the daily traffic data sets to determine the best regression tree model(s) to predict a day in certain characterization. The results show that not only do the regression tree models have accurate prediction ability of vehicle speed and promising ability to estimate travel time, but also the regression tree models built upon other characterizations are preferred to predict a certain characterization. The loop-detector data on PORTAL (Portland Oregon Regional Transportation Archive Listing) system, for the I5-I205 loop in Portland, Oregon, is used to demonstrate the applicability of regression trees in this report.
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| Blowing Dust Final Report |
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An Expiramental Blowing Dust Alarm System for Highways - Interim Report
Blowing dust storms pose a visibility hazard to highway motorists. An experimental alarm which senses electrification of a metal antenna by blowing dust particles is described. The metal antenna can be an ordinary radio whip antenna or an insulated top strand of barbed-wire right of way fence to monitor a greater area. The sensor responded favorably under conditions of half mile visibility and 20 mph winds. Field tests were conducted by telemetry to an office microcomputer.
Dust related radio noise which blanks out broadcast reception is attributed to electrification of metallic objects and subsequent corona or spark discharge.
An experimental acoustic sensor for blowing sand is also described, along with comment on application of an ionization chamber to detect motionless dust.
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| Deck Joint Seals - Interim |
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Experimental Deck Joint Seals - Interim
In 1971, the Oregon State Highway Division began to participate in the National Experimental and Evaluation Program (NEEP) Project No. 11 – “Development of Watertight Bridge Deck Joint Seals.” The purpose of this program was to evaluate several new proprietary bridge deck expansion joint seals which were claimed to prevent unsightly and structural damaging moisture leakage.
A work plan was developed whereby inspections were to be made at final inspection when the structure was completed, at six months after installation and annually thereafter for a minimum of three years. The latter requirement was changed to two annual inspections, specifically during the months of January and July. This change ensured inspections during extreme weather conditions.
The performance of the joints was rated in four general areas:
1. Did the joint leak?
2. Was the joint damaged?
3. Was the joint noisy under traffic?
4. What was the ride-ability quality?
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| Deck Joints - Final |
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Experimental Deck Joint Seals - Final Report
The problems resulting from the failure to obtain durable watertight bridge deck joint seals prompted the Oregon State Highway Division in 1970 to participate in Project 11 of the National Experimental and Evaluation Program. This project was initiated to evaluate both proprietary and nonproprietary deck joint seals on a nationwide basis. Thirty-six states agreed to participate in this study, which promised to save maintenance costs of repairing bridge bearings and other structural elements due to non-functioning deck joint seals. Preventing the loss of esthetics because of unsightly water stains increased the appeal of this study.
In Oregon, the study of bridge deck joint seals consisted of semi-annual inspections of a select group of seals by regional bridge inspectors. These inspections were scheduled for times of extreme weather conditions. The joint seals selected for examination varied from nonproprietary single cell units to elaborate proprietary modular and reinforced molded units.
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| Expansion Bearing Study - Interim |
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Experimental Expansion Bearing Study - Interim
The Oregon State Highway Division has undertaken an inspection program to gather data on several expansion devices. To date, six bearings have been included in the Category 2 Experimental Expansion Bearing Study. Three of the six bearings have been appraised as operating well, two have been found to be damaged and one was not evaluated since it had just been installed.
The information recorded during the inspections covered the amount of movement of the bearing, weather conditions during inspection, condition of the bearing and remarks pertinent to any repairs that were made or were to be made to the bearing. The inspections were scheduled during January and July in an attempt to record data during extreme weather conditions.
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| Expansion Bearing Study - Final |
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Experimental Expansion Bearing Study
A study to evaluate the effectiveness and serviceability of bridge expansion bearings was undertaken by the Oregon State Highway Division in 1972. The evaluation was conducted under the provisions of the Experimental Features Program of the Federal Highway Administration. Initially, a work plan containing four bearing assemblies and outlining the proposed evaluation method was submitted to the Federal Highway Administration for inclusion in their Experimental Features Program. Subsequently, two additional bearing assemblies were added shortly after the study began.
To accomplish the evaluation, a detailed inspection of each bearing was specified to be performed by the Regional Bridge Inspectors on an annual basis. This inspection frequency was later changed to twice a year and specifically during the months of January and July in order to witness performance during extreme weather conditions. The data requested during each inspection included the following items:
- Condition of the bearing.
- Performance of the bearing.
- Specific repairs to the bearing.
- Ambient temperature and weather conditions during the inspection.
- Amount of bearing movement.
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| Flexible Guideposts |
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Experimental Use of Flexible Guideposts in Oregon
During the early months of 1971 the Oregon State Highway Division requested and received FHWA approval to install flexible guideposts in locations where sight post losses from collisions would be expected to be high. The request was to install the flexible posts as an experimental feature under the provisions of PPM 20-6.3 as a Category 2 Project. Limited use of the posts was initiated in contracts let during the spring of 1971. When used, they were installed in exit gore areas and on interchange ramps having curvature of 11 degrees or more. Also, at flared and channelized intersections having heavy turning movements, flexible guideposts have been used to delineate the turning radii in each quadrant.
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| Shredded Tires |
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Experimental Project Use of Shredded Tires for Lightweight Fill
Shredded rubber tires have been used as Lightweight fill in repair of a landslide that occurred under a highway embankment in mountainous terrain on Highway US 42 (Oregon state route #35). The force driving the slide was decreased by removing the soil embankment and replacing it with a lighter weight embankment constructed with shredded tire chips. The tire embankment has a three-foot-thick compacted soil cap on the top and side-slopes and supports a conventional aggregate base and asphalt pavement. 5800 tons of shredded tires were used - approximately 580,000 tires. Cost of the tires delivered to the site was $30/ton reduced by a $20/ton reimbursement from Oregon DEQ; net $l0/ton ($7/yd). Cost of placing and compacting the tires was $8.33/ton: ($5.85/yd). Total cost of the tire fill at final in-place density was $18.33/ton ($12.87/yd). Surface monuments, settlement plates, and slope inclinometers have been installed to monitor the performance of the embankment.
Shredded tire chips were transported to the project site in “live-bottom" trailers from vendors located 150 to 200 miles from the project. The trailers each carried 28 tons of tires. The tire chips were placed and compacted in three-foot lifts using a D-8 dozer. Density (unit weight) of the tire chips was on the order of 30 per when "loose" in the haul vehicle, 45 pcf compacted in-place, and 52 pcf when compressed under the soil cap and pavement. The 12.5-foot-thick section of compacted tire embankment compressed 20 inches (13.4%) under the capping load. Few construction problems were encountered. Exposed wires in the tire chips caused tire punctures on dump trucks.
Pavement surface deflections were measured using a falling weight deflectometer. Deflections were twice as great as would be expected of the same pavement over an earth embankment. Vibrations similar to those felt when standing on a bridge can be felt by a person standing on the embankment when a heavy truck crosses it.
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| Fabric Reinforcement |
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Experimental Use of Fabric Reinforcement in Flexible Pavement Overlay of Deteriorated Asphalt Paveme
Many Oregon highways are in need of an asphalt overlay treatment to correct deficiencies such as fatigue cracking, deformation and other distresses and provide an acceptable riding surface. These asphalt concrete overlays tend to experience reflective cracking. It was proposed to use a full width geo-textile fabric to retard reflective cracking.
The purpose of this study was to evaluate the effectiveness of a Non-woven polypropylene fabric to retard or eliminate reflective cracking. The product chosen was Petromat Non-woven Fabric produced by Phillips Fibers Corporation. This is the final report describing the performance of the Petromat fabric membrane which was installed in July 1978.
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| Traffic Delineators |
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Experimental Use of Temporary Traffic Delineators
During construction, there is a safety need to provide highly visible channelizing delineation for temporary protection and direction of traffic. "Super Duck" Surface Mounted Delineator (SDR-328, Rounded) by Carsonite is marketed to meet that safety need.
The purpose of this study was to evaluate "Super Duck's" visibility and ability to remain in-place after vehicular impact thus not requiring any maintenance. This is the final report describing the performance of "Super Duck" which was installed on the Sutton Lake-Florence Project in January 1988.
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| Hot-In-Place Recycling |
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Exploratory Study of Hot-In-Place Recycling of Asphalt Pavements Volume II
Hot-in-place recycling (HIR) is a method for rehabilitation of asphalt pavements. Potential for cost savings and resource preservation are high because existing pavement materials are processed on-site, with only the addition of small amounts of recycling agent.
The Oregon Department of Transportation (ODOT) constructed HIR projects in 1992 and 1993. In September 1992, ODOT contracted with Oregon State University (OSU) to evaluate the HIR projects, synthesize existing information on HIR, and develop guidelines for HIR use. This report summarizes the information developed during the study:
- Construction equipment used on ODOT HIR projects is discussed.
- Field data tom six HIR projects are presented.
- Results of a limited laboratory investigation of HIR are presented.
- Proper project selection was found to be extremely critical to HIR success. A selection procedure is presented.
- Based on information from the field studies and a limited laboratory testing program, a recommended mix design procedure is presented.
This report is in two volumes. Volume I includes the body of the report, Volume II includes the appendices.
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| Fiberoptic Signs - Ladd |
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Fiberoptic Variable Message Signs - Ladd Canyon
The SYLVIA® fiber optic variable message signs (VMS) were installed on the Old Oregon Trail Highway (1-84) at milepost 263.4 near La Grande and at milepost 286.7 near North Powder. The purpose of the signs is to warn motorists of fog, winter blizzard conditions and high wind conditions.
The evaluation of the SYLVIA® fiber optic VMS was conducted by the Oregon Department of Transportation staff as part of an Experimental Features Program research project. The issues of reliability and ease of operation were investigated. These signs have functioned well, overall. Legibility of the signs is excellent in the conditions evaluated, the maintenance requirements have been minor, the cost of operation has been reasonable, and driver compliance has been excellent. An additional benefit is that the length of time required to close the highway is significantly lower, since the signs aid maintenance personnel with informing drivers of the closure.
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| Fiberoptic Signs - Swift |
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Fiberoptic Variable Message Signs - Swift Interchange
The SYLVIA® fiber optic variable message signs (VMS) were installed on the Pacific Highway (I-5) as a part of the "Swift Interchange - Delta Park Interchange" project at milepost 298.47 and at milepost 305.66 in January 1991. Initially, during project construction, the signs were used to provide road construction and delay information to the motoring public. Currently, the signs are being utilized to provide event information, and/or road delay conditions as part of the Freeway Management System.
The evaluation of the SYLVIA® fiber optic VMS was conducted by the Oregon Department of Transportation staff as part of an Experimental Features Program research project. The issues of reliability and ease of operation were investigated. These signs have functioned well, overall. Legibility of the signs is excellent in the conditions evaluated, the maintenance requirements have been minor, and the cost of operation has been reasonable.
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| Concrete Detention Pond |
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Fiber Reinforced Concrete Detention Pond
This project involves the construction of two polypropylene fiber reinforced concrete lined detention ponds. The detention ponds are located on the north side of the 181st Avenue Interchange on the Columbia River Highway 0-84) approximately ten miles east of Portland in Multnomah County, Oregon. The project was completed in the autumn of 1991. The original design called for the detention ponds to be constructed with six inch thick, continuous, welded wire, fabric reinforced concrete over an impermeable geomembrane. An alternate to this design, replacing the welded wire fabric reinforced concrete with polypropylene fiber reinforced concrete, was proposed by the contractor through a no cost price agreement. The decision was made by Oregon Department of Transportation (ODOT) and Federal Highway Administration (FHWA) staff to accept the contractor's proposal and to evaluate the material as an experimental features project.
The replacement of welded wire fabric reinforced concrete with polypropylene fiber reinforced concrete created no problems with respect to mixing, placement, workability, finish-ability, or visual appearance. The use of fiber reinforced concrete on this project resulted in a small cost reduction relative to the use of welded wire fabric reinforced concrete.
The fiber reinforced concrete should continue to be monitored to ensure that its functional performance is acceptable. If no problems with long-term functional performance are encountered, fiber reinforced concrete should be considered as an alternate to the welded wire fabric reinforced concrete for similar projects in the future.
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| Soil Nailing Construction Report |
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Soil Nailing of a Bridge Fill Embankment Construction Report
Soil nailing as an alternative lateral earth support method has recently been introduced in Oregon to build the first permanent Soil -Nailed Wall on the State's Highway System.
The soil nailing technique was used for an underpass widening to provide for additional traveling lanes under the existing Oregon Slough Bridge in Portland,
Oregon. The project required removal of the existing south end slope and the construction of a Soil-Nailed Wall in front of the pile-supported end bent to permanently retain the existing bridge fill embankment.
Construction and post-construction monitoring was performed t o study the new wall's performance.
This is the first of a five-paper sequence describing the results of ODOT's extensive investigation into the soil nailing technique as an alternative to more conventional bridge embankment retention methods.
Based on the results of our study, it may be concluded that:
- The soil nailing technique is a viable lateral earth support system to retain an existing bridge fill embankment and to allow for a roadway widening under a bridge.
- The selection of the soil nailing support system was based on economic considerations.
This technique enabled
- considerable cost savings to the owner,
- the project to proceed without disrupting overhead bridge or adjacent roadway traffic,
- the Contractor to work in low overhead clearance conditions, and
- the Contractor to quickly alter his construction procedure to fit soil conditions.
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