13 resultados para 84-566C
em Iowa Publications Online (IPO) - State Library, State of Iowa (Iowa), United States
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Iowa Code § 8D.10 requires certain state agencies prepare an annual report to the General Assembly certifying the identified savings associated with that state agency’s use of the Iowa Communications Network (ICN). This report covers estimated cost savings related to video conferencing via ICN for the Iowa Department of Transportation (DOT). In FY 2008, the DOT did not conduct any sessions utilizing ICN’s video conferencing system. Therefore, no cost savings were calculated for this report.
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Introduction and summary Iowa Code § 8D.10 requires certain state agencies to prepare an annual report to the General Assembly certifying the identified savings associated with that state agency’s use of the Iowa Communications Network (ICN). This report covers estimated cost savings related to video conferencing via ICN for the Iowa Department of Transportation (DOT). In FY 2010, the DOT did not conduct any sessions utilizing ICN’s video conferencing system. Therefore, no cost savings were calculated for this report.
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Bureau of Nutrition and Health Promotion part of the Iowa Department of Public Health produces of weekly newsletter about the Iowa WIC Program for the State of Iowa citizen.
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This report is a brief summary of research on the effect of longitudinal drains on subgrade support. The Iowa DOT began installing longitudinal subdrains at a depth of 24" in 1978. The trend in Iowa has been to deeper longitudinal drains with the present standard being 48" deep. A very limited amount of data would indicate that the deeper longitudinal drains are providing a greater benefit to the subgrade support value. The 24# deep drains of the Poweshiek Interstate 80 project yielded a spring subgrade support value of 165. The 30" deep drains on Pottawattamie Interstate 80 yielded a K value of 170 while the 48"deep drains on Cass County Interstate 80 yielded a K value of 210. This limited amount of data would indicate that the deeper drains provide greater benefit to improvement of the subgrade support values.
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Class A, B, and C concrete paving mixes were tested for compressive strength at 40°F and 73°F, both with and without fly ash substitution for 15% of the portland cement. Two Class C ashes and one Class F ash from Iowa approved sources were examined in each mix. The purpose of the study was to provide data on cool weather strength development of concrete paving mixes utilizing Iowa materials. In all cases except one, the fly ash concretes exhibited lower 7 and 28- day compressive strengths at 40°F than control mixes. The continuation of the October 15 cut-off date for the use of fly ash concrete is recommended.
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Fly ash was used in this evaluation study to replace 15% of the cement in Class D-57 structural concrete containing ASTM C494 Type B, retarding admixtures. Two Class "C" ashes and one Class "F" ash from Iowa approved sources were examined in each mix. When Class "C" ashes were used, they were substituted on the basis of 1.0 pound for each pound of cement removed. When Class "F" ash was used, it was substituted on the basis of 1.25 pounds of ash for each pound of cement removed. Compressive strengths of the retarded mixes, with and without fly ash, were determined at 7, 28 and 56 days of age. In most cases, with few exceptions, the mixes containing the fly ash exhibited higher strengths than the same concrete mix without the fly ash. The exceptions were the 7, 28, and 56 days of the mixes containing Class F ash. The freeze/thaw durability of the concrete studied was not affected by the presence of fly ash. The data obtained suggested that the present Class D-57 structural concrete mix with retarding admixtures can be modified to allow the substitution of 15% of the cement with an approved fly ash when Class III coarse aggregates are used. Setting times of the concretes were not materially changed due to the incorporation of fly ash.
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In recent years the Iowa DOT has shifted emphasis from the construction of new roads to the maintenance and preservation of existing highways. A need has developed for analyzing pavements structurally to select the correct rehabilitation strategy and to properly design a pavement overlay if necessary. This need has been fulfilled by Road Rater testing which has been used successfully on all types of pavements to evaluate pavement and subgrade conditions and to design asphaltic concrete overlays. The Iowa Road Rater Design Method has been simplified so that it may be easily understood and used by the widely diverse groups of individuals which may be involved in pavement restoration and management. Road Rater analysis techniques have worked well to date and have been verified by pavement coring, soils sampling and testing, and pavement removal by block sampling. Void detection testing has also been performed experimentally in Iowa, and results indicate that the Road Rater can be used to locate pavement voids and that Road Rater analysis techniques are reasonably accurate. The success of Road Rater research and development has made deflection test data one of the most important pavement management inputs.
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Des Moines River Plat Maps.
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Des Moines River Plat Maps.
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Des Moines River Plat Maps.
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Des Moines River Plat Maps.
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This past winter the sieve analysis of combined aggregate was investigated. This study was given No. 26 by the Central Laboratory. The purpose of this work was to try and develop a sieve analysis procedure for combined aggregate which is less time consuming and has the same accuracy as the method described in I.M. 304. In an attempt to use a variety of aggregates for this investigation, a request was made to each District Materials Office to obtain at least 3 different combined aggregate samples in their respective districts. At the same time it was also requested that the field technician test these samples, prior to submitting them to the Central Laboratory. The field technician was instructed to test each sample as described in method I.M. 304 and also by a modified AASHTO T27 method which will be identified in the report as Method A. The modified AASHTO Method A was identical to T27 with the exception that a smaller sample is used for testing. The field technicians submitted the samples, test results and also comments regarding the modified AASHTO procedure. The general comments of the modified AASHTO procedure were: The method was much simpler to follow; however, it took about the same amount of time so there was no real advantage. After reviewing AASHTO T27, T164, I.M. 304 and Report No. FHWA-RD-77-53 another test method was purposed. Report No. FHWA-RD-77-53 is a report prepared by FHWA from data they gathered concerning control practices and shortcut or alternative test methods for aggregate gradation. A second test method was developed which also was very similar to AASHTO T27, The test procedure for this method is attached and is identified as Method B. The following is a summary of test results submitted by the Field Technicians and obtained by the aggregate section of the Central Laboratory.
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All noncomplying penetration and absolute viscosity results must be verified before being reported. This verification of test results is done by reheating and retesting the identical sample that is suspect. The District Laboratories are required to submit penetration and absolute viscosity correlation samples to the Central Laboratory. These samples are the identical ones tested by the District Laboratories. When the Central laboratory tests these correlation samples they are also considered to be reheated and retested. Reheating a sample will harden the asphalt to some degree and possibly cause a change in the test results. This investigation was conducted to determine how much change in penetration and absolute viscosity could be expected by reheating and retesting asphalt samples.