Field Demonstration of Foamed Asphalt Muscatine County, HR-257, 1988

The foamed asphalt concept has been around since the 1950's. Rising oil prices have created a renewed interest in this process. The purpose of this project was to construct an asphalt base using the foamed asphalt process and to evaluate its performance. A 4.2 mile length of Muscatine County road A-91 was selected for the research project. Asphalt contents of 4.5% and 5.5%, moisture contents of 70% and 90% of optimum, and fog, single chip, and double chip seal coats were used in various combinations to lay 9 test sections of 4-inch foamed asphalt base. After five years of service and evaluation, several conclusions can be made concerning the performance of the foamed asphalt bases: (1) the foamed asphalt process can work as shown by the excellent performance of Sections 2 and 3; (2) foamed asphalt base requires a well compacted subgrade and a road profile suitable for good drainage of water--test section failures were mostly due to a poor subgrade and subsurface moisture; and (3) when the base is placed in two or more lifts, extreme care must be exercised to insure adequate bonding is achieved between lifts. Any future research with foamed asphalt should include various asphalt depths in order to determine a thickness/strength relationship for foamed asphalt.

Thermoplastic Pavement Markings, HR-172, 1975

It is difficult to maintain reflectorized lane markings on high-traffic, multi-lane highways. This is particularly true of sections in urban areas where there are frequent lane changes, such as on the Des Moines Freeway, I-235. In spite of the fact that the lane markings are painted on an average of three times a year, they are frequently absent during a considerable portion of the winter period. In the summer of 1973, the office of Highway Maintenance suggested a research project using a new thermoplastic paint developed by the Prismo Universal Corporation. Because of difficulties in scheduling the work, a definite proposal was not submitted until 1974. Upon the recommendation of the Iowa Highway Research Board, the project was approved by the Iowa State Highway Commission on August 7, 1974.

Iowa Drainage Laws (Annotated), HR-46 and Iowa Highway Research Board Bulletin No. 6, 1957

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.

Temporary Traffic Control and Enforcement of Traffic Laws in Closed Road Sections, June 2007

Public travel by motor vehicles is often necessary in road and street sections that have been officially closed for construction, repair, and/or other reasons. This authorization is permitted in order to provide access to homes and businesses located beyond the point of closure. The MUTCD does address appropriate use of specific regulatory signs at the entrance to closed sections; however, direct guidance for temporary traffic control measures within these areas is not included but may be needed. Interpretation and enforcement of common practices may vary among transportation agencies. For example, some law enforcement officers in Iowa have indicated a concern regarding enforcement and jurisdiction of traffic laws in these areas because the Code of Iowa only appears to address violations on roadways open to “public travel.” Enforcement of traffic laws in closed road sections is desirable to maintain safety for workers and for specifically authorized road users. In addition, occasional unauthorized entry by motor vehicles is experienced in closed road areas causing property damage. Citations beyond simple trespass may be advisable to provide better security for construction sites, reduce economic losses from damage to completed work, and create safer work zones.

Investigation of PCC Pavement Sections from I-29 Pottawattamie County, MLR-06-01, 2007

Early deterioration has shown up in a number of Iowa PCC pavements placed between 1986 and 1994. Research has shown that inadequate air content and spacing factors have contributed to the deterioration. Ettringite infilling of air voids is nearly always noted in cores obtained from pavements exhibiting deterioration. This research is to document the early deterioration on I-29 in Pottawattamie county from MP 59 to 72 in both directions.