26 resultados para consistency
em Iowa Publications Online (IPO) - State Library, State of Iowa (Iowa), United States
Resumo:
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.
Resumo:
A two-stage mixing process for concrete involves mixing a slurry of cementitious materials and water, then adding the slurry to coarse and fine aggregate to form concrete. Some research has indicated that this process might facilitate dispersion of cementitious materials and improve cement hydration, the characteristics of the interfacial transition zone (ITZ) between aggregate and paste, and concrete homogeneity. The goal of the study was to find optimal mixing procedures for production of a homogeneous and workable mixture and quality concrete using a two-stage mixing operation. The specific objectives of the study are as follows: (1) To achieve optimal mixing energy and time for a homogeneous cementitious material, (2) To characterize the homogeneity and flow property of the pastes, (3) To investigate effective methods for coating aggregate particles with cement slurry, (4) To study the effect of the two-stage mixing procedure on concrete properties, (5) To obtain the improved production rates. Parameters measured for Phase I included: heat of hydration, maturity, and rheology tests were performed on the fresh paste samples, and compressive strength, degree of hydration, and scanning electron microscope (SEM) imaging tests were conducted on the cured specimens. For Phases II and III tests included slump and air content on fresh concrete and compressive and tensile strengths, rapid air void analysis, and rapid chloride permeability on hardened concrete.
Resumo:
This report describes how Iowa compares to other states in the nation. To promote consistency, the Iowa totals and the other states’ information have been taken entirely from the FBI’s national publication called Crime in the United States; 1999. The Iowa information in Crime in the United States; 1999 is based upon actual summary totals for selected reporting jurisdictions and produced by the U.S. Department of Justice, F.B.I. These Iowa totals cannot be compared to the 1999 Incident-Based Iowa Uniform Crime Reports, which are based on actual totals for all reporting Iowa law enforcement jurisdictions.
Resumo:
This report describes how Iowa compares to other states in the nation. To promote consistency, the Iowa totals and the other states’ information have been taken entirely from the FBI’s national publication called Crime in the United States; 2000. The Iowa information in Crime in the United States; 2000 is based upon actual summary totals for selected reporting jurisdictions and produced by the U.S. Department of Justice, F.B.I. These Iowa totals cannot be compared to the 2000 Incident-Based Iowa Uniform Crime reports, which are based on actual totals for all reporting Iowa law enforcement jurisdictions.
Resumo:
This report describes how Iowa compares to other states in the nation. To promote consistency, the Iowa totals and the other states’ information have been taken entirely from the FBI’s national publication called Crime in the United States; 2001. The Iowa information in Crime in the United States; 2001 is based upon actual summary totals for selected reporting jurisdictions and produced by the U.S. Department of Justice, F.B.I. These Iowa totals cannot be compared to the 2001 Incident-Based Iowa Uniform Crime Reports, which are based on actual totals for all reporting Iowa law enforcement jurisdictions.
Resumo:
This report describes how Iowa compares to other states in the nation. To promote consistency, the Iowa totals and the other states’ information have been taken entirely from the FBI’s national publication called Crime in the United States; 1998. The Iowa information in Crime in the United States; 1998 is based upon actual summary totals for selected reporting jurisdictions and produced by the U.S. Department of Justice, F.B.I. These Iowa totals cannot be compared to the 1998 Incident-Based Iowa Uniform Crime Reports which are based on actual totals for all reporting Iowa law enforcement jurisdictions.
Validation of the New Mix Design Process for Cold In-Place Rehabilitation Using Foamed Asphalt, 2007
Resumo:
Asphalt pavement recycling has grown dramatically over the last few years as a viable technology to rehabilitate existing asphalt pavements. Iowa's current Cold In-place Recycling (CIR) practice utilizes a generic recipe specification to define the characteristics of the CIR mixture. As CIR continues to evolve, the desire to place CIR mixture with specific engineering properties requires the use of a mix design process. A new mix design procedure was developed for Cold In-place Recycling using foamed asphalt (CIR-foam) in consideration of its predicted field performance. The new laboratory mix design process was validated against various Reclaimed Asphalt Pavement (RAP) materials to determine its consistency over a wide range of RAP materials available throughout Iowa. The performance tests, which include dynamic modulus test, dynamic creep test and raveling test, were conducted to evaluate the consistency of a new CIR-foam mix design process to ensure reliable mixture performance over a wide range of traffic and climatic conditions. The “lab designed” CIR will allow the pavement designer to take the properties of the CIR into account when determining the overlay thickness.
Resumo:
This Manual is designed to help targeted communities organize and train local steering groups and task force leaders. The Ongoing Covenant with Black Iowa (OCBI) model will engage and empower African Americans in various communities to work together in developing strategies that bridge local priorities to statewide goals. Trained Task Force Leaders play a critical role in establishing productive dialogue and planning that is essential to moving the OCBI forward in meeting its goals. They must ensure consistency within each Task Force as the OCBI is a multilevel partnership and collaboration among local communities, the Commission on the Status of African Americans and the Covenant with Black America. Task Force Leaders assist with constructive dialogue among local residents to engage and focus on the issues, and work collectively towards a solution. Patience in developing a strategy and trained Task Force Leaders are essential to the success of the OCBI. It is our hope that this Manual will serve as a guide to assist you in all aspects of building your local strategic plan.
Resumo:
Per legislative requirement, attached is the Iowa Department of Transportation’s summary of project status for infrastructure projects that have been appropriated revenue from various funds including Rebuild Iowa Infrastructure, Health Restricted Capitals, Bridge Safety, Revenue Bonds Capitals, and Revenue Bonds Capitals II. Although a status report for the Bridge Safety Fund was already submitted to the directors of LSA and DOM, a status report on those projects is also included within this attachment for consistency with last year’s reporting. In addition, per request from LSA, status reports for the FY 2011 passenger rail appropriation from the Underground Storage Tank Fund and the FY 2010 Commercial Service Vertical Infrastructure appropriation from the General Fund are also listed in this report.
Resumo:
Executive Summary I. Survey The Task Force conducted a wide-ranging survey of more than 9,000 licensed Iowa attorneys and judges to obtain their input on a variety of civil justice system topics. The survey results helped inform the Task Force of problem areas in Iowa’s civil justice system. II. Two-Tier Justice System The Task Force recommends a pilot program based on a two-tier civil justice system. A two-tier system would streamline litigation processes—including rules of evidence and discovery disclosures—and reduce litigation costs of certain cases falling below a threshold dollar value. III. One Judge/One Case and Date Certain for Trial Some jurisdictions in Iowa have adopted one judge/one case and date certain for trial in certain cases. The assignment of one judge to each case for the life of the matter and the establishment of dates certain for civil trials could enhance Iowans’ access to the courts, improve judicial management, promote consistency and adherence to deadlines, and reduce discovery excesses. IV. Discovery Processes Reforms addressing inefficient discovery processes will reduce delays in and costs of litigation. Such measures include adopting an aspirational purpose for discovery rules to “secure the just, speedy, and inexpensive determination of every action,” holding discovery proportional to the size and nature of the case, requiring initial disclosures, limiting the number of expert witnesses, and enforcing existing rules. V. Expert Witness Fees The Task Force acknowledges the probable need to revisit the statutory additional daily compensation limit for expert witness fees. Leaving the compensation level to the discretion of the trial court is one potential solution. VI. Jurors Additions to the standard juror questionnaire would provide a better understanding of the potential jurors’ backgrounds and suitability for jury service. The Task Force encourages adoption of more modern juror educational materials and video. Rehabilitation of prospective jurors who express an unwillingness or inability to be fair should include a presumption of dismissal. VII. Video and Teleconferencing Options When court resources are constrained both by limited numbers of personnel and budget cuts, it is logical to look to video and teleconferencing technology to streamline the court process and reduce costs. The judicial branch should embrace technological developments in ways that will not compromise the fairness, dignity, solemnity, and decorum of judicial proceedings. VIII. Court-Annexed Alternative Dispute Resolution(ADR) Litigants and practitioners in Iowa are generally satisfied with the current use of private, voluntary ADR for civil cases. There is concern, however, that maintaining the status quo may have steep future costs. Court-annexed ADR is an important aspect of any justice system reform effort, and the Task Force perceives benefits and detriments to reforming this aspect of the Iowa civil justice system. IX. Relaxed Requirement of Findings of Fact and Conclusions of Law A rule authorizing parties to waive findings of fact and conclusions of law could expedite resolution of nonjury civil cases. X. Business (Specialty) Courts Specialty business courts have achieved widespread support across the country. In addition, specialty courts provide excellent vehicles for implementing or piloting other court innovations that may be useful in a broader court system context. A business specialty court should be and could be piloted in Iowa within the existing court system framework of the Iowa Judicial Branch. Appendix included as a separate document, is 176 pages.
Resumo:
The present research project was designed to determine thermal properties, such as coefficient of thermal expansion (CTE) and thermal conductivity, of Iowa concrete pavement materials. These properties are required as input values by the Mechanistic-Empirical Pavement Design Guide (MEPDG). In this project, a literature review was conducted to determine the factors that affect thermal properties of concrete and the existing prediction equations for CTE and thermal conductivity of concrete. CTE tests were performed on various lab and field samples of portland cement concrete (PCC) at the Iowa Department of Transportation and Iowa State University. The variations due to the test procedure, the equipment used, and the consistency of field batch materials were evaluated. The test results showed that the CTE variations due to test procedure and batch consistency were less than 5%, and the variation due to the different equipment was less than 15%. Concrete CTE values were significantly affected by different types of coarse aggregate. The CTE values of Iowa concrete made with limestone+graval, quartzite, dolomite, limestone+dolomite, and limestone were 7.27, 6.86, 6.68, 5.83, and 5.69 microstrain/oF (13.08, 12.35, 12.03, 10.50, and 10.25 microstrain/oC), respectively, which were all higher than the default value of 5.50 microstrain/oF in the MEPDG program. The thermal conductivity of a typical Iowa PCC mix and an asphalt cement concrete (ACC) mix (both with limestone as coarse aggregate) were tested at Concrete Technology Laboratory in Skokie, Illinois. The thermal conductivity was 0.77 Btu/hr•ft•oF (1.33 W/m•K) for PCC and 1.21 Btu/hr•ft•oF (2.09 W/m•K) for ACC, which are different from the default values (1.25 Btu/hr•ft•oF or 2.16 W/m•K for PCC and 0.67 Btu/hr•ft•oF or 1.16 W/m•K for ACC) in the MEPDG program. The investigations onto the CTE of ACC and the effects of concrete materials (such as cementitious material and aggregate types) and mix proportions on concrete thermal conductivity are recommended to be considered in future studies.
Resumo:
The Federal Highway Administration (FHWA) and the Iowa and Illinois Departments of Transportation (Iowa DOT and IDOT) have identified the Selected Alternative for improving Interstate 74 (I-74) from its southern terminus at Avenue of the Cities (23rd Avenue) in Moline, Illinois to its northern terminus one mile north of the I-74 interchange with 53rd Street in Davenport, Iowa. The Selected Alternative identified and discussed in this Record of Decision is the preferred alternative identified in the Final Environmental Impact Statement (FEIS). The purpose of the proposed improvements is to improve capacity, travel reliability, and safety along I-74 between its termini, and provide consistency with local land use planning goals. The need for the proposed improvements to the I-74 corridor is based on a combination of factors related to providing better transportation service and sustaining economic development.
Resumo:
In the last decade, Intelligent Transportation Systems (ITS) have increasingly been deployed in work zones by state departments of transportation. Also known as smart work zone systems they improve traffic operations and safety by providing real-time information to travelers, monitoring traffic conditions, and managing incidents. Although there have been numerous ITS deployments in work zones, a framework for evaluating the effectiveness of these deployments does not exist. To justify the continued development and implementation of smart work zone systems, this study developed a framework to determine ITS effectiveness for specific work zone projects. The framework recommends using one or more of five performance measures: diversion rate, delay time, queue length, crash frequency, and speed. The monetary benefits and costs of ITS deployment in a work zone can then be computed using the performance measure values. Such ITS computations include additional considerations that are typically not present in standard benefit-cost computations. The proposed framework will allow for consistency in performance measures across different ITS studies thus allowing for comparisons across studies or for meta analysis. In addition, guidance on the circumstances under which ITS deployment is recommended for a work zone is provided. The framework was illustrated using two case studies: one urban work zone on I-70 and one rural work zone on I-44, in Missouri. The goals of the two ITS deployments were different – the I-70 ITS deployment was targeted at improving mobility whereas the I-44 deployment was targeted at improving safety. For the I-70 site, only permanent ITS equipment that was already in place was used for the project and no temporary ITS equipment was deployed. The permanent DMS equipment serves multiple purposes, and it is arguable whether that cost should be attributed to the work zone project. The data collection effort for the I-70 site was very significant as portable surveillance captured the actual diversion flows to alternative routes. The benefit-cost ratio for the I-70 site was 2.1 to 1 if adjusted equipment costs were included and 6.9 to 1 without equipment costs. The safety-focused I-44 ITS deployment had an estimated benefit-cost ratio of 3.2 to 1.
Resumo:
The objectives of this research were the collection and evaluation of the data pertaining to the importance of concrete mixing time on air content and distribution, consolidation and workability for pavement construction. American Society for Testing and Materials (ASTM) standard C 94 was used to determine the significance of the mixing time on the consistency of the mix being delivered and placed on grade. Measurements of unit weight, slump, air content, retained coarse aggregate and compressive strength were used to compare the consistency of the mix in the hauling unit at the point of mixing and at the point placement. An analysis of variance was performed on the data collected from the field tests. Results were used to establish the relationship between selected mixing time and the portland cement concrete properties tested. The results were also used to define the effect of testing location (center and side of truck, and on the grade) on the concrete properties. Compressive strength test concepts were used to analyze the hardened concrete pavement strength. Cores were obtained at various locations on each project on or between vibrator locations to evaluate the variance in each sample, between locations, and mixing times. A low-vacuum scanning electron microscope (SEM) was used to study air void parameters in the concrete cores. Combining the data from these analysis thickness measurements and ride in Iowa will provide a foundation for the formulation of a performance based matrix. Analysis of the air voids in the hardened concrete provides a description of the dispersion of the cemtitious materials (specifically flyash) and air void characteristics in the pavement. Air void characteristics measured included size, shape and distribution.
Resumo:
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.