Council Bluffs Interstate System Improvements Project Pottawattamie County, IA and Douglas County, Nebraska, July 19, 2005

The Iowa Department of Transportation (Iowa DOT), Nebraska Department of Roads (NDOR), and the Federal Highway Administration (FHWA) are proposing improvements to the interstate system in the Omaha/Council Bluffs metropolitan area, extending across the Missouri River on Interstate 80 (I-80) to east of the Interstate 480 (I-480) interchange in Omaha, Nebraska (see Figure 1-1). The study considers long-term, broad-base transportation improvements along Interstate I-29 (I-29), I-80, and I-480, including approximately 18 mainline miles of interstate and 14 interchanges (3 system1, 11 service), that would add capacity and correct functional issues along the mainline and interchanges and upgrade the I-80 Missouri River Crossing. These improvements, once implemented, would bring the segments of I-80 and I-29 up to current engineering standards and modernize the roadway to accommodate future traffic needs.

Pavement Surface on Macadam Base: Adair County Final Report, Iowa Highway Reserach Board Project HR-209

The quality and availability of aggregate for pc concrete stone varies across Iowa. Southwest Iowa is one area of the state that is short of quality aggregates. The concrete stone generally available in the area is limestone from the Argentine or Winterset ledges with an overburden of up to 150 feet. This concrete stone is classified as Class 1 durability and is susceptible to 'ID"-cracking. In addition, the general engineering soil classification rates the soils of southwest Iowa as having the poorest subgrade bearing characteristics in the state. 1 The combination of poor soils and low quality aggregate has contributed to premature deterioration of many miles of portland cement concrete pavement. Research project HR-209 was initiated in 1979 to explore alternative construction methods that may produce better pavements for southwest Iowa.

Iowa Research with Chem-Crete Bitumen: Final Report Iowa Highway Research Board Project HR-226, June 1986

With the spiraling cost of construction, coupled with inflation, engineers must develop and research new techniques to better utilize the public's dollar. One area i n which these new technologies must be researched is in the field of highway construction; more specifically, asphalt products. There are areas within the state of Iowa which do not have Class I aggregate readily available for asphalt concrete road construction. The cost of transporting higher quality aggregate specified in the "Standard Specifications for Highway and Bridge construction"' for construction projects is escalating on a yearly basis. Many counties will be squeezed out of the construction of new roadways if an alternative to the high costs is not identified. The same high costs will curtail adequate upkeep on the existing paved system and will result in decreased serviceability. For this reason, a product is needed to better utilize the local aggregates for road construction and maintenance. There i s a product on the market which the promoters claim will improve the prer?nt asphalt to such a degree as to "upgrade deficient aggregates" to the level they can be used in today's standard construction techniques. This product is "Chem-Crete Bitumen," a'kpecially refined asphalt" that was promoted by Chem-Crete Corporation of Menlo Park, California. Chemkrete Technologies, Inc. of Wickliffe, Ohio; a wholly owned subsidiary of the Lubrizol Corporation has since purchased the U.S.

An Engineering Study to Update the Iowa Transportation Laws Annotated: HR 324a January 1995

Research project HR-234A was sponsored by the Iowa Highway Research Board and the Iowa Department of Transportation. In the preparation of this compilation of highway and street laws of Iowa, an attempt has been made to include those sections of the Iowa Code Annotated and Iowa Digest to which reference is frequently required by the Department of Transportation, counties, cities and towns in their conduct of highway and street administration, construction and maintenance. This publication is offered with the hope and belief that it will prove to be of value and assistance to those concerned with the problems of establishing, maintaining and administering a highway and street program. Because of the broad scope of highway and street work and the many interrelated provisions of Iowa law, and usable size, some Code provision which are insignificant to the principal subject were omitted out of necessity; others were omitted to avoid repetition. A general index is provided at the end of the text of this volume. Each major topic is divided into subtopics and is accompanied by appropriate Code sections. Specific section numbers as they appear in the Code are in.

Engineering Study for Reducing Sign Vandalism Final Report Highway Research Advisory Board Projec HR 246, June 1992

Sign vandalism has traditionally been a vexing problem for Iowa counties. The extent of the cost and incidence of these acts have never been fully ascertained, but a 1990 survey indicated that they cost Iowa counties more than 1.5 million dollars annually. In 1990, the Iowa Legislature recognized the seriousness of the problem and strengthened the existing sign vandalism law by increasing the penalty for illegal possession of a traffic control device from a simple to a serious misdemeanor. However, the courts must be willing to prosecute vandals to the magnitude provided in the Iowa Code. An educational campaign begun in 1987 involving over 200 Iowa school districts to educate students on the seriousness of the problem evidently did not have the effect of dramatically reducing the overall cost of sign vandalism in Iowa. This study sought to define the scope of the problem and possibly offer some effective countermeasures to combat sign vandalism and theft in Iowa.

Signing on Very Low Volume Rurd Roads Iowa DOT Project HR-262, July, 1984

Research was undertaken to define an appropriate level of use of traffic control devices on rural secondary roads that carry very low traffic volumes. The goal of this research was to improve the safety and efficiency of travel on the rural secondary road system. This goal was to be accomplished by providing County Engineers with guidance concerning the cost-effective use of traffic control devices on very low volume rural roads. A further objective was to define the range of traffic volumes on the roads for which the recommendations would be appropriate. Little previous research has been directed toward roads that carry very low traffic volumes. Consequently, the factual input for this research was developed by conducting an inventory of the signs and markings actually in use on 2,069 miles of rural road in Iowa. Most of these roads carried 15 or fewer vehicles per day. Additional input was provided by a survey of the opinions of County Engineers and Supervisors in Iowa. Data from both the inventory and the opinion survey indicated a considerable lack of uniformity in the application of signs on very low volume rural roads. The number of warning signs installed varied from 0.24 per mile to 3.85 per mile in the 21 counties in which the inventory was carried out. The use of specific signs not only varied quite widely among counties but also indicated a lack of uniform application within counties. County officials generally favored varying the elaborateness of signing depending upon the type of surface and the volume of traffic on different roads. Less elaborate signing would be installed on an unpaved road than on a paved road. A concensus opinion was that roads carrying fewer than 25 vehicles per day should have fewer signs than roads carrying higher volumes. Although roads carrying 0 to 24 vehicles per day constituted over 24% of the total rural secondary system, they carried less than 3% of the total travel on that system. Virtually all of these roads are classified as area service roads and would thus be expected to carry only short trips primarily by local motorists. Consequently, it was concluded that the need for warning signs rarely can be demonstrated on unpaved rural roads with traffic volumes of fewer than 25 vehicles per day. It is recommended that each county designate a portion of its roads as an Area Service Level B system. All road segments with very low traffic volumes should be considered for inclusion in this system. Roads included in this system may receive a lesser level of maintenance and a reduced level of signing. The county is also afforded protection from liability arising from accidents occurring on roads designated as part of an Area Service Level B system. A uniform absence of warning signs on roads of this nature is not expected to have any discernible effect on the safety or quality of service on these very low volume roads. The resources conserved may be expended more effectively to upgrade maintenance and traffic control on roads carrying higher volumes where the beneficial effect on highway safety and service will be much more consequential.

Design and Performance Verifcation of Ultra-High Performance Concrete Piles for Deep Foundations Final Report, November 2008

The strategic plan for bridge engineering issued by AASHTO in 2005 identified extending the service life and optimizing structural systems of bridges in the United States as two grand challenges in bridge engineering, with the objective of producing safer bridges that have a minimum service life of 75 years and reduced maintenance cost. Material deterioration was identified as one of the primary challenges to achieving the objective of extended life. In substructural applications (e.g., deep foundations), construction materials such as timber, steel, and concrete are subjected to deterioration due to environmental impacts. Using innovative and new materials for foundation applications makes the AASHTO objective of 75 years service life achievable. Ultra High Performance Concrete (UHPC) with compressive strength of 180 MPa (26,000 psi) and excellent durability has been used in superstructure applications but not in geotechnical and foundation applications. This study explores the use of precast, prestressed UHPC piles in future foundations of bridges and other structures. An H-shaped UHPC section, which is 10-in. (250-mm) deep with weight similar to that of an HP10×57 steel pile, was designed to improve constructability and reduce cost. In this project, instrumented UHPC piles were cast and laboratory and field tests were conducted. Laboratory tests were used to verify the moment-curvature response of UHPC pile section. In the field, two UHPC piles have been successfully driven in glacial till clay soil and load tested under vertical and lateral loads. This report provides a complete set of results for the field investigation conducted on UHPC H-shaped piles. Test results, durability, drivability, and other material advantages over normal concrete and steel indicate that UHPC piles are a viable alternative to achieve the goals of AASHTO strategic plan.

Evaluation of Low Cost Traffic Calming for Rural Communities – Phase II, April 2013

The main goal of the research described in this report was to evaluate countermeasures that agencies can use to reduce speeds as drivers enter rural communities located on high-speed roadways. The objectives of this study were as follows: * Identify and summarize countermeasures used to manage speeds in transition zones * Demonstrate the effectiveness of countermeasures that are practical for high- to low-speed transition zones * Acquire additional information about countermeasures that may show promise but lack sufficient evidence of effectiveness * Develop an application toolbox to assist small communities in selecting appropriate transition zones and effective countermeasures for entrances to small rural communities The team solicited small communities that were interested in participating in the Phase II study and several communities were also recommended. The treatments evaluated were selected by carefully considering traffic-calming treatments that have been used effectively in other countries for small rural communities, as well as the information gained from the first phase of the project. The treatments evaluated are as follows: * Transverse speed bars * Colored entrance treatment * Temporary island * Radar-activated speed limit sign * Speed feedback sign The toolbox publication and four focused tech briefs also cover the results of this work.

A Comparison of Mobile Scanning to a Total Station Survey at the I-35 and IA 92 Interchange in Warren County, Iowa, August 15, 2012

The purpose of this project was to investigate the potential for collecting and using data from mobile terrestrial laser scanning (MTLS) technology that would reduce the need for traditional survey methods for the development of highway improvement projects at the Iowa Department of Transportation (Iowa DOT). The primary interest in investigating mobile scanning technology is to minimize the exposure of field surveyors to dangerous high volume traffic situations. Issues investigated were cost, timeframe, accuracy, contracting specifications, data capture extents, data extraction capabilities and data storage issues associated with mobile scanning. The project area selected for evaluation was the I-35/IA 92 interchange in Warren County, Iowa. This project covers approximately one mile of I-35, one mile of IA 92, 4 interchange ramps, and bridges within these limits. Delivered LAS and image files for this project totaled almost 31GB. There is nearly a 6-fold increase in the size of the scan data after post-processing. Camera data, when enabled, produced approximately 900MB of imagery data per mile using a 2- camera, 5 megapixel system. A comparison was done between 1823 points on the pavement that were surveyed by Iowa DOT staff using a total station and the same points generated through the MTLS process. The data acquired through the MTLS and data processing met the Iowa DOT specifications for engineering survey. A list of benefits and challenges is included in the detailed report. With the success of this project, it is anticipate[d] that additional projects will be scanned for the Iowa DOT for use in the development of highway improvement projects.

Development of Performance Properties of Ternary Mixtures: Field Demonstrations and Project Summary, TPF-5(117), 2012

Supplementary cementitious materials (SCM) have become common parts of modern concrete practice. The blending of two or three cementitious materials to optimize durability, strength, or economics provides owners, engineers, materials suppliers, and contractors with substantial advantages over mixtures containing only portland cement. However, these advances in concrete technology and engineering have not always been adequately captured in specifications for concrete. Users need specific guidance to assist them in defining the performance requirements for a concrete application and the selection of optimal proportions of the cementitious materials needed to produce the required durable concrete. The fact that blended cements are currently available in many regions increases options for mixtures and thus can complicate the selection process. Both Portland and blended cements have already been optimized by the manufacturer to provide specific properties (such as setting time, shrinkage, and strength gain). The addition of SCMs (as binary, ternary, or even more complex mixtures) can alter these properties, and therefore has the potential to impact the overall performance and applications of concrete. This report is the final of a series of publications describing a project aimed at addressing effective use of ternary systems. The work was conducted in several stages and individual reports have been published at the end of each stage.

Evaluation of Low Cost Traffic Calming for Rural Communities – Phase II [Updated], TR-630, October, 2013

The main goal of the research described in this report was to evaluate countermeasures that agencies can use to reduce speeds as drivers enter rural communities located on high-speed roadways. The objectives of this study were as follows: * Identify and summarize countermeasures used to manage speeds in transition zones * Demonstrate the effectiveness of countermeasures that are practical for high- to low-speed transition zones * Acquire additional information about countermeasures that may show promise but lack sufficient evidence of effectiveness * Develop an application toolbox to assist small communities in selecting appropriate transition zones and effective countermeasures for entrances to small rural communities The team solicited small communities that were interested in participating in the Phase II study and several communities were also recommended. The treatments evaluated were selected by carefully considering traffic-calming treatments that have been used effectively in other countries for small rural communities, as well as the information gained from the first phase of the project. The treatments evaluated are as follows: * Transverse speed bars * Colored entrance treatment * Temporary island * Radar-activated speed limit sign * Speed feedback sign The toolbox publication and four focused tech briefs also cover the results of this work.

Soft Photogrammetry for Highway Engineering, HR-387, 1998

The SoftPlotter, a soft photogrammetric software and Silicon Graphics workstation, was used to evaluate the accuracy of soft photogrammetry and identify applications of this technology to highway engineering. A comparative study showed that SoftPlotter compares well with other software such as Socket and Integraph. The PC software TNTMips is inexpensive but needs further development to be comparable to SoftPlotter. The Campus Project showed that soft photogrammetry is accurate for traditional photogrammetric applications. It is also accurate for producing orthophoto and base maps for Geographic Information Systems (GISs). The Highway Project showed that soft photogrammetry is accurate for highway engineering and that the technical staff at the Iowa Department of Transportation (IA DOT) can be easily trained in this new technology. The research demonstrated that soft photogrammetry can be used with low-flight helicopter photography for large-scale mapping in highway engineering. The researchers recommend that research be conducted to test the use of digital cameras instead of the traditional aerial cameras in helicopter photography. Research that examines the use of soft photogrammetry with video logging imagery for inventory and GIS studies in highway maintenance is also recommended. Research is also warranted into the integration of soft photogrammetry with virtual reality, which can be used in three-dimensional designing and visualization of highways and subdivisions in real time. The IA DOT owns one analytical plotter and two analogue plotters. The analytical plotter is used for aerial triangulation, and the analogue plotters are used for plotting. However, neither is capable of producing orthophotos. Therefore, the researchers recommend that the IA DOT purchase soft photogrammetric workstations for orthophoto production, and if and when required, use it for aerial triangulation and plotting. In the future, the analogue plotters may become obsolete. At that time, the researchers recommend that the analogue plotters be phased out and replaced by soft photogrammetric workstations.

Engineering Study for the Evaluation of Public Road Administration and Maintenance Alternatives, HR-265, 1985

Iowa's public road system of 112,000 miles is one of the largest and the best in the nation. It represents a considerable financial investment of taxpayer revenues over the years. And, it requires a sustained investment to preserve an economical level of transport service into the future. In 1982, a Governor's Blue Ribbon Transportation Task Force evaluated the effectiveness of Iowa's entire transportation system. Four important Task Force recommendations dealt with public road administrative issues in Iowa. These issues were related to: (1) Design criteria and levels of maintenance; (2) Consistency in the use of standards among jurisdictions; (3) Consolidation of maintenance operations at one jurisdiction level; and (4) Jurisdicational authority for roads; The issues formed the background for Research Project HR-265.

Asphalt Emulsions for Highway Construction, HR-216, 1985

A 5.8 mile section of Dubuque County (Iowa) Road D-53 was selected for this project, the objective of which were to: 1. identify a cost effective asphalt emulsion bound macadam typical cross section; 2. determine the effectiveness of engineering fabric placed under macadam roadbeds; and 3. evalaute the use of emulsions in surface seal coats. A number of conclusions were reached: 1. The minus #200 sieve material for the macadam stone should be held to a minimum. For the emulsion used on this project, the minus #200 material had less than 4 percent to achieve satisfactory coating of the macadam stone. 2. The placement of the emulsion treated macadam required no additional equipment or time than the plain macadam placement. 3. Emulsion treating the macadam stone for the shoulder base appears unnecessary. 4. The emulsion treated macadam base beneath an asphaltic concrete wearing surface yielded a higher structural rating than the plain macadam beneath a comparable ashaltic concrete surface. 5. The performance of the fabric between the subgrade and the macadam base to prevent soil intrusion into the base could not be determined by the non-destructive testing conducted. 6. When no choke stone is used over the macadam base, allowance for ac mix overrun should be made. 7. Use of an emulsion instead of a cutback asphalt saved money and energy. However, the poor performance of the seal coat negated any real savings.

Low Cost Techniques of Base Stabilization, HR-312, 1994

This project was initiated in 1988 to study the effectiveness of four different construction techniques for establishing a stable base on a granular surfaced roadway. After base stabilization, the roadway was then seal coated, eliminating dust problems associated with granular surfaced roads. When monies become available, the roadway can be surfaced with a more permanent structure. A 2.8 mi (4.5 km) section of the Horseshoe Road in Dubuque County was divided into four divisions for this study. This report discusses the procedures used during construction of these different divisions. Problems and possible solutions have been analyzed to better understand the capabilities of the materials and construction techniques used on the project. The project had the following results: High structural ratings and soil K factors for the BIO CAT and Consolid bases did not translate to good roadway performance; the macadam base had the best overall performance; the tensar fabric had no noticeable effect on the macadam base; and the HFE-300 performed acceptably.