Electronic Bulletin Board System, HR-345, 1998

The primary objectives of the Electronic Bulletin Board System (BBS) project were to: (1) Provide an electronic communication tool which would link city and county engineering offices to each other and to other governmental agencies for messaging and data sharing; (2) Provide a dial-up site for reference information or files accessible on-demand; and (3) Provide a "stepping stone" to the world of electronic data transfer, recognizing that most local government employees face a huge complex of technology with limited knowledge of computers and communications tools. The system was designed to be as simple as possible, and to require minimal equipment and software cost to the users. The original system was an Apex 386/25 computer with MS-DOS 5.0 software and the final configuration was an HP Vectra XM Pentium 90 with MS-NT 3.51 and Mustang - Wildcat 5.0 software. The users of the BBS were county engineers and their staff, offices in the central office of the Iowa Department of Transportation (DOT) and Resident Construction Engineers at the Iowa DOT. Much of the activity was between the county engineers, and their staffs, and the Iowa DOT offices with which they have ongoing business activities. The BBS contained files for mapping, Internet e-mail service, Accident Location Analysis System (ALAS) data, Iowa DOT bid lettings, and Autocad and Intergraph maps and standards. The 800 line calls were recorded and gave the best indication of the usage and the trends that were being followed. The usage tended to be higher in the winter months when design activities are occurring and lower in the summer months when the construction is in progress. The project was judged a success. The BBS did provide a "stepping stone" to the world of electronic data transfer.

A Statistical Analysis of Iowa Premature Concrete Pavement Deterioration, Supplementary Study, HR-1063, 1997

This supplementary project has been undertaken as an effort to continue work previously completed in the Pooled Fund Study of Premature Concrete Pavement Deterioration. As such, it shares the objective of "Identifying the variables that are present in those pavements exhibiting premature deterioration," by collecting additional data and performing statistical analysis of those data. The approach and philosophy of this work are identical to that followed in the above project, and the Pooled Fund Study Final Report provides a detailed description of this process. This project has involved the collection of data for additional sites in the state of Iowa. These sites have then been added to sites collected in the original study, and statistical analysis has been performed on the entire set. It is hoped that this will have two major effects. First, using data from only one state allows for the analysis of a larger set of independent variables with a greater degree of commonality than was possible in the multi-state study, since the data are not limited by state to state differences in data collection and retention. Second, more data on additional sites will increase the degrees of freedom in the model and hopefully add confidence to the results.

Iowa's CHLOE Profilometer Correlation Procedure, MLR-87-10, 1987

The Iowa DOT has been correlating its roadmeters to the CHLOE Profilometer since 1968. The same test method for the Present Serviceability Index (PSI) deduction from the pavement condition (crack and patch) survey has also been used since 1968. Resulting PSI measurements on the Interstate and Primary Highway Systems have had good continuity through the years due to these test procedures. A computer program called PSITREND has been developed to plot PSI versus year tested for every rural pavement section in the State of Iowa. PSITREND provides pavement performance trends which are very useful for prediction of rehabilitation needs and for evaluation of new designs or rehabilitation techniques. The PSITREND data base should be maintained through future years to expand on nineteen years of historical PSI test information already collected.

Factors Influencing Stability of Granular Base Course Mixes, Progress Report, HR-99, 1965

The problems of laboratory compaction procedures, the effect of gradation and mineralogy on shearing strength, and effect of stabilizing agents on shearing strength of granular base course mixes are discussed. For the materials tested, a suitable laboratory compaction procedure was developed which involves the use of a vibratory table to prepare triaxial test specimens. A computer program has been developed to facilitate the analysis of the test data of the effect of gradation and mineralogy on shearing strength of soils. The effects of the following materials have been selected for evaluation as stabilizing agents’ portland cement, sodium and calcium chloride, lime organic cationic waterproofer, and asphaltic materials.

Factors Influencing Stability of Granular Base Course Mixes, Progress Report, HR-99, 1964 (April)

The problems of laboratory compaction procedures, the effect of gradation and mineralogy on shearing strength, and effect of stabilizing agents on shearing strength of granular base course mixes are discussed. For the materials tested, a suitable laboratory compaction procedure was developed which involves the use of a vibratory table to prepare triaxial test specimens. A computer program has been developed to facilitate the analysis of the test data of the effect of gradation and mineralogy on shearing strength of soils. The effects of the following materials have been selected for evaluation as stabilizing agents’ portland cement, sodium and calcium chloride, lime organic cationic waterproofer, and asphaltic materials.

Void Ratio and Shear Strength of Two Compacted Crushed Stones, Progress Report, HR-99

Triaxial compression tests of two crushed limestones of differing highway service records indicate a fundamental difference in their shear strength -- void ratio relationship. Analyses were based on stress parameters at minimum sample volume, i.e., before there was significant sample dilation due to shear. The better service record sample compacted to higher density, and had a high effective angle of internal friction and zero effective cohesion. The other sample compacted to lower density and had a lower friction angle, but gained significant stability from effective cohesion. Repeated loading-unloading cycles reduced the cohesion, apparently due to modification of the sample structure. Extrapolations of the results to zero void ratio agree with sliding friction data reported on calcite, or with triaxial parameters reported on carbonate rocks.

Accelerated Testing Track, HR-7, 1951

In May 1950 a proposal for a research project was submitted to the newly formed Iowa Highway Research Board for consideration and action. This project, designated RPSl by the Board, encompassed the study, development, preparation of preliminary plans and specifications for the construction of a wheel track to be used in the accelerated testing of highway pavements. The device envisioned in the proposal was a circular track about seventy-five feet in diameter equipped with a suitable automobile-tired device to test pavements about five feet in width laid into the track under regular construction practices by small scale construction equipment. The Board, upon review, revised and expanded the basic concepts of the project. The project as revised by the Board included a study of the feasibility of developing, constructing and operating an accelerated testing track in which pavements, bases and subgrades may be laid one full lane, or at least ten feet, in width by full size construction equipment in conformity with usual construction practices. The pavements so laid are to be subjected, during test, to conditions as nearly simulating actual traffic as possible.

A Study to Correlate Soil Consistency Limits with Soil Moisture Tensions, HR-27, 1965

The liquid and plastic limits of a soil are consistency limits that were arbitrarily chosen by Albert Atterberg in 1911. Their determination is by strictly empirical testing procedures. Except for the development of a liquid limit device and subsequent minor refinements the method has remained basically unchanged for over a half century. The empirical determination of an arbitrary limit would seem to be contrary to the very foundations of scientific procedures. However, the tests are relatively simple and the results are generally acceptable and valuable in almost every conceivable use of soil from an engineering standpoint. Such a great volume of information has been collected and compiled by application of these limits to cohesive soils, that it would be impractical and virtually impossible to replace the tests with a more rational testing method. Nevertheless, many believe that the present method is too time consuming and inconsistent. Research was initiated to investigate the development of a rapid and consistent method by relating the limits to soil moisture tension values determined by porous plate and pressure membrane apparatus. With the moisture tension method, hundreds of samples may be run at one time, operator variability is minimal, results are consistent, and a high degree of correlation to present liquid limit tests is possible.

A History of Particle-Size Limits, Special Report, HR-99

Soils consist largely of mineral particles in a wide range of sizes. It is advantageous to assign names, such as "sand", etc., to describe particles which lie between certain size limits. These names are convenient to use and give more information than merely stating that the particles fit certain size limitations. Many systems of particle-size limits have been proposed and used, and have many discrepancies. For example, depending on the system used, a term such as "sand" may designate very different materials. Since no clear-cut divisions can be made between members of a continuous series all particle-size limit schemes are arbitrary. The originators of the various systems were influenced by many factors: convenience of investigation, methods and equipment available for analysis, ease of presenting data, convenience for statistical analysis, previous work, and systems in use. The complications were further compounded because of widely varying fields of endeavor with varying background, outlook, and goals. For example, many inconsistencies are found in engineering depending on whether the size limits are used to differentiate soils, or characterize aggregates for concrete. Some of the investigators have tried to place limits to correspond with the various properties of the soil components; others were more interested in the ease and convenience of obtaining and presenting data. The purpose of this paper is to review many of the systems which have been proposed and used, and if possible, to suggest what may have been the reasons for the selection of the particle-size limits.

Effect of CA-Montmorillonite Expansion on X-Ray Diffraction Intensities, Progress Report, HR-111, 1966

The most abundant clay mineral group in Iowa soils is montmorillonite, most commonly calcium-saturated (Hanway et al, 1960). The calcium montmorillonite-water system was therefore selected for detailed X-ray study. Montmorillonite is unusual among minerals in that it has an expanding lattice in the c direction. That is, upon wetting with water, the individual silicate layers separate to allow entry of water, and the mineral expands. Characteristics of this expansion are readily studied by means of X-ray diffraction: the X-ray diffraction angle gives the average layer-to-layer "d001" spacing for any given moisture condition; the sharpness of the diffraction peak is a measure of uniformity of the d001 spacing; and the intensity of the peak relates to uniformity of the d001 spacing and in addition to the electron density distribution within the repeating elements. The latter is embodied in the "structure factor".

Quantitative X-Ray Diffraction Measurements by Fast Scanning, HR-111

Two goals were pursued in this research: first, to evaluate statistically some effects of sample preparation and instrument geometry on reproducibility of X-ray diffraction intensity data; and second, to develop a procedure for finding minimum peak and background counting times for a desired level of accuracy. The ratio of calcite to dolomite in limestones was determined in trials. Ultra-fine wet grinding of the limestone in porcelain impact type ball mill gave most consistent X-ray results, but caused considerable line broadening, and peaks were best measured on an area count basis. Sample spinning reduced variance about one third, and a coarse beam-medium detector slit arrangement was found to be best. An equation is developed relating coefficient of variation of a count ratio to peak and background counts. By use of the equation or graphs the minimum coefficient of variation is predicted from one fast scan, and the number and optimum arrangement of additional counting periods to reduce variation to a desired limit may be obtained. The calculated coefficient is the maximum which may be attributed to the counting statistic but does not include experimental deviations.

A Computer Based Information System for County Equipment Cost Records, Interim Report, HR-173, 1975

This report describes the work accomplished to date on research project HR-173, A Computer Based Information System for County Equipment Cost Records, and presents the initial design for this system. The specific topics discussed here are findings from the analysis of information needs, the system specifications developed from these findings, and the proposed system design based upon the system specifications. The initial system design will include tentative input designs for capturing input data, output designs to show the output formats and the items to be output for use in decision making, file design showing the organization of information to be kept on each piece of equipment in the computer data file, and general system design explaining how the entire system will operate. The Steering Committee appointed by Iowa Highway Research Board is asked to study this report, make appropriate suggestions, and give approval to the proposed design subject to any suggestions made. This approval will permit the designer to proceed promptly with the development of the computer program implementation phase of the design.

Floods of September 15-16, 1992, in the Thompson, Weldon, and Chariton River Basins, South-Central Iowa, HR-140, 1997

Water-surface-elevation profiles and peak discharges for the floods of September 15-16, 1992, in the Thompson, Weldon, and Chariton River Basins, south-central Iowa, are presented in this report. The profiles illustrate the 1992 floods along the Thompson, Weldon, Chariton, and South Fork Chariton Rivers and along Elk Creek in the south-central Iowa counties of Adair, Clarke, Decatur, Lucas, Madison, Ringgold, Union, and Wayne. Water-surface-elevation profiles for the floods of July 4, 1981, along the Chariton River in Lucas County and along the South Fork Chariton River in Wayne County also are included in the report for comparative purposes. The September 15-16, 1992, floods are the largest known peak discharges at gaging stations Thompson River at Davis City (station number 06898000) 57,000 cubic feet per second, Weldon River near Leon (station number 06898400) 76,200 cubic feet per second, Chariton River near Chariton (station number 06903400) 37,700 cubic feet per second, and South Fork Chariton River near Promise City (station number 06903700) 70,600 cubic feet per second. The peak discharges were, respectively, 1.7, 2.6, 1.4, and 2.1 times larger than calculated 100-year recurrence-interval discharges. The report provides information on flood stages and discharges and floodflow frequencies for streamflow-gaging stations in the Thompson, Weldon, and Chariton River Basins using flood information collected through 1995. Information on temporary bench marks and reference points established in the Thompson and Weldon River Basins during 1994-95, and in the Chariton River Basin during 1983-84 and 1994-95, also is included in the report. A flood history summarizes rainfall conditions and damages for floods that occurred during 1947, 1959, 1981, 1992, and 1993.

Examination of Highway Maintenance Garages in the U.S. 30 Corridor between Ames and Cedar Rapids, 1988

A linear programming model is used to optimally assign highway segments to highway maintenance garages using existing facilities. The model is also used to determine possible operational savings or losses associated with four alternatives for expanding, closing and/or relocating some of the garages in a study area. The study area contains 16 highway maintenance garages and 139 highway segments. The study recommends alternative No. 3 (close Tama and Blairstown garages and relocate new garage at Jct. U.S. 30 and Iowa 21) at an annual operational savings of approximately $16,250. These operational savings, however, are only the guidelines for decisionmakers and are subject to the required assumptions of the model used and limitations of the study.

Technology News, April 1983

Technology News is a newsletter produced by the Iowa Department of Transportation to provide information to the transportation specialist in Iowa's cities and counties. Technology News is one of CTRE's primary avenues for exchanging transportation-related information with local agencies. The bimonthly newsletter gives an up-to-date look to the up-to-date information our 2,500+ readers have grown to expect.