22 resultados para colate detritiche, terreni granulari, prove triax ACU e CSD
Resumo:
Many reports have been written concerning investigations of concrete sealants. The primary concern of most investigators is the protection of bridge decks from de-icing chemicals which cause surface scaling and, when allowed to permeate to reinforcing steel, result in deep spalling and general concrete deterioration. The problem of protecting abutments and pier tops from salt solutions entails a significantly different approach than the problem of protecting bridge decks. The epoxy resins become eligible as a protective material since one need not be concerned with slipperiness or its abrasive characteristics. Protection with linseed oil at regular intervals would prove bothersome because of the inaccessibility of pier tops after the deck is placed. The primary purpose of this investigation was to evaluate various commercial products in terms of their ability to prevent concrete scaling of bridge abutments and pier tops which are subject to salt water deterioration.
Resumo:
Research project HR-234 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 Code 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. Because of the broad scope of highway and street work and the many interrelated provisions of Iowa law, and in the interests of keeping this volume in a convenient and usable size, some Code provisions which have some bearing on the principal subject were of necessity omitted. The volume has been compiled in loose leaf form with the expectation that periodic updates will keep the reader informed regarding changes in the law and/or new laws. A general index is provided at the end of the text of this volume. Each major topic is divided into relevant subtopics and are accompanied by appropriate Code sections. 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 system. The reader is cautioned to consult legal counsel on all matters beyond the scope of this text.
Resumo:
The purpose of this Interstate Corridor Plan (plan) is to provide the Iowa Department of Transportation (Iowa DOT) with an initial screening and prioritization of interstate corridors/segments. This process evaluates the entire interstate system, independent of current financial constraints, using a select group of criteria weighted in terms of their relative significance. The resulting segments would then represent those areas that should be considered for further study (e.g., environmental, design, engineering), with the possibility of being considered for programming by the Iowa Transportation Commission. There was a dominant theme present in conversations with those department stakeholders who have a keen interest in the product of this planning effort. A statement that was often heard was that staff needed more information to help answer the question, “Where do we need to be looking to next, and when?” There was a strong desire to be able to use this plan to help populate that initial pool of candidate segments that would progress towards further study, as discussed below. It was this theme that framed the need for this plan and ultimately guided its development. Further study: As acknowledged at the beginning of this section, the product of this planning effort will be an initial screening and prioritization of interstate corridors/segments. While this initial screening will assist the Iowa DOT in identifying those areas that should be considered for further study, the plan will not identify specific projects or alternatives that could be directly considered as part of the programming process. Bridging the gap between this plan and the programming process are a variety of environmental, design, and engineering activities conducted by various Iowa DOT offices. It is these activities that will further refine the priority corridors/segments identified in this plan into candidate projects. In addition, should the evaluation process developed through this planning effort prove to be successful, it is possible that there will be additional applications, such as future primary system highway plans and statewide freight plans.
Resumo:
The issue of corrosion of winter maintenance equipment is becoming of greater concern because of the increased use of liquid solutions of ice control chemicals, as opposed to their application in solid form. Being in liquid form, the ice control chemicals can more easily penetrate into the nooks and crannies on equipment and avoid being cleansed from the vehicle. Given this enhanced corrosive ability, methods must be found to minimize corrosion. The methods may include coatings, additives, cleansing techniques, other methods, and may also include doing nothing, and accepting a reduced equipment lifetime as a valid (perhaps) trade off with the enhanced benefits of using liquid ice control chemicals. In reality, some combination of these methods may prove to be optimal. Whatever solutions are selected, they must be relatively cheap and durable. The latter point is critical because of the environment in which maintenance trucks operate, in which scrapes, scratches and dents are facts of life. Protection methods that are not robust simply will not work. The purpose of this study is to determine how corrosion occurs on maintenance trucks, to find methods that would minimize the major corrosion mechanisms, and to
Resumo:
In the preparation of this compilation of drainage laws of Iowa, an attempt has been made to include those sections of the Code to which reference is frequently required by the State Highway Commission, Boards of Supervisors and County Engineers in the conduct of highway and road administration as it is affected by the Iowa drainage laws. Of necessity some Code provisions which have a bearing on the principal subject were omitted. Enactments of the 56th General Assembly which modify existing code sections have been included as part of the regular text of the Code sections included in this publication. THE USER IS CAUTIONED THAT THESE CODE SECTIONS, AS MODIFIED BY THE 56th GENERAL ASSEMBLY, ARE NOT A PART OF THE 1954 CODE OF IOWA AND ARE OFFICIAL ONLY INSOFAR AS THEY ARE PRINTED IN THE OFFICIAL PUBLICATION ACTS OF THE 56TH GENERAL ASSEMBLY. SINCE THE 57TH GENERAL ASSEMBLY IS IN SESSION DURING THE PRINTING OF THIS PUBLICATION, ENACTMENTS OF THAT BODY WHICH AMEND OR REPEAL SECTIONS SET OUT HEREIN ARE INCLUDED IN THE BACK OF THIS VOLUME ON THE PINK-COLORED PAPER. THE USER IS CAUTIONED IN USING THIS VOLUME TO REFER TO THE TABLE OF SECTIONS REPEALED OR AMENDED, ON THE PINK-COLORED PAPER AT THE BACK OF THIS VOLUME. 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 administering a highway, road and drainage system.
Resumo:
This Phase I report describes a preliminary evaluation of a new compaction monitoring system developed by Caterpillar, Inc. (CAT), for use as a quality control and quality assurance (QC/QA) tool during earthwork construction operations. The CAT compaction monitoring system consists of an instrumented roller with sensors to monitor machine power output in response to changes in soil machine interaction and is fitted with a global positioning system (GPS) to monitor roller location in real time. Three pilot tests were conducted using CAT’s compaction monitoring technology. Two of the sites were located in Peoria, Illinois, at the Caterpillar facilities. The third project was an actual earthwork grading project in West Des Moines, Iowa. Typical construction operations for all tests included the following steps: (1) aerate/till existing soil; (2) moisture condition soil with water truck (if too dry); (3) remix; (4) blade to level surface; and (5) compact soil using the CAT CP-533E roller instrumented with the compaction monitoring sensors and display screen. Test strips varied in loose lift thickness, water content, and length. The results of the study show that it is possible to evaluate soil compaction with relatively good accuracy using machine energy as an indicator, with the advantage of 100% coverage with results in real time. Additional field trials are necessary, however, to expand the range of correlations to other soil types, different roller configurations, roller speeds, lift thicknesses, and water contents. Further, with increased use of this technology, new QC/QA guidelines will need to be developed with a framework in statistical analysis. Results from Phase I revealed that the CAT compaction monitoring method has a high level of promise for use as a QC/QA tool but that additional testing is necessary in order to prove its validity under a wide range of field conditions. The Phase II work plan involves establishing a Technical Advisor Committee, developing a better understanding of the algorithms used, performing further testing in a controlled environment, testing on project sites in the Midwest, and developing QC/QA procedures.
Resumo:
The objective of this research project was to evaluate the construction and service performance of ammonium phosphate/fly ash (APFA) treated base courses of crushed fines and/or unprocessed sand. Specific test results related to construction of the test sections were included in the 1987 construction report by Iowa State University. The performance of the experimental sections is dealt with in this final report. This 1986 project demonstrated that in all cases the control sections utilizing a Type B base experienced dramatically less cracking in the surface than the APFA treated base sections. The cost per mix and subsequent surface maintenance costs for the APFA base sections, especially those having a substantial amount of limestone, were higher than the Type B base control sections. This type of construction may prove to be economical only when petroleum product costs escalate.