Ultra-Thin Portland Cement Concrete Overlay Extended Evaluation, January 2005

In this day of the mature highway systems, a new set of problems is facing the highway engineer. The existing infrastructure has aged to or past the design life of the original pavement design. In many cases, increased commercial traffic is creating the need for additional load carrying capacity, causing state highway engineers to consider new alternatives for rehabilitation of existing surfaces. Alternative surface materials, thicknesses, and methods of installation must be identified to meet the needs of individual pavements and budgets. With overlays being one of the most frequently used rehabilitation alternatives, it is important to learn more about the limitations and potential performance of thin bonded portland cement overlays and subsequent rehabilitation. The Iowa ultra-thin project demonstrated the application of thin portland cement concrete overlays as a rehabilitation technique. It combined the variables of base preparation, overlay thickness, slab size, and fiber enhancement into a series of test sections over a 7.2-mile length. This report identifies the performance of the overlays in terms of deflection reduction, reduced cracking, and improved bonding between the portland cement concrete (PCC) and asphalt cement concrete (ACC) base layers. The original research project was designed to evaluate the variables over a 5-year period of time. A second project provided the opportunity to test overlay rehabilitation techniques and continue measurement of the original overlay performance for 5 additional years. All performance indicators identified exceptional performance over the 10-year evaluation period for each of the variable combinations considered. The report summarizes the research methods, results, and identifies future research ideas to aid the pavement overlay designer in the successful implementation of ultra-thin portland cement concrete overlays as an lternative pavement rehabilitation technique.

Reaudit letter to the City of Ottumwa for the period July 1, 2005 through June 30, 2006, as well as certain issues applicable to the year ended June 30, 2005 and subsequent periods

Reaudit letter to the City of Ottumwa for the period July 1, 2005 through June 30, 2006, as well as certain issues applicable to the year ended June 30, 2005 and subsequent periods

Report on a review of selected general and application controls over the Iowa Department of Administrative Service’s (DAS) Human Resource Information System (HRIS), Payroll, Integrated Information for Iowa (I/3) and E-Payment Engine Systems for the periods April 13, 2009 through May 15, 2009 and April 5, 2010 through May 7, 2010

Report on a review of selected general and application controls over the Iowa Department of Administrative Service’s (DAS) Human Resource Information System (HRIS), Payroll, Integrated Information for Iowa (I/3) and E-Payment Engine Systems for the periods April 13, 2009 through May 15, 2009 and April 5, 2010 through May 7, 2010

Iowa Traffic Control Devices and Pavement Markings: A Manual for Cities and Counties April 2001

Iowa Traffic Control Devices and Pavement Markings: A Manual for Cities and Counties has been developed to provide state and local transportation agencies with suggestions and examples related to traffic control devices and pavement markings. Both rural and urban applications are included. The primary source of information for this document is the Manual on Uniform Traffic Control Devices (MUTCD), but many additional references have also been used. A complete listing of these is included in the appendix to this manual, and the reader is invited to consult these references for more in-depth information. The contents of this manual are not intended to represent standard practice or to imply legal requirements for installation in any particular manner. This document should be used as a supplement to the MUTCD, not as a substitute for any requirements contained therein. Engineering judgement should be applied to all decisions regarding traffic control devices and pavement markings. All references to the MUTCD in this manual apply to the millennium edition. The reader should be aware that many millennium revisions are allowed phase-in periods by the Federal Highway Administration (FHWA), ranging from two to ten years. These extended compliance periods should be considered when making decisions regarding traffic control devices and pavement markings. A new addition to the MUTCD, Part 5, “Traffic Control Devices for Low-Volume Roads,” also contains valuable recommendations for signing and marking low volume roads. This manual is presented in an easy to use threering format. Topics included in the complete guide manual may not apply to all jurisdictions and can easily be removed or modified as desired. Desired millennium MUTCD sections may be added for quick reference using the divider at the end of this document. Contents may also be available on CD-ROM in the future.

Ultrathin Portland Cement Concrete Overlay Extended Evaluation, Construction Report, TR-432, 2000

In recent years, ultra-thin whitetopping (UTW) has evolved as a viable rehabilitation technique for deteriorated asphalt cement concrete (ACC) pavement. Numerous UTW projects have been constructed and tested, enabling researchers to identify key elements contributing to their successful performance. These elements include foundation support, interface bonding condition, portland cement concrete (PCC) overlay thickness, synthetic fiber reinforcement usage, joint spacing, and joint sealing. The interface bonding condition is the most important of these elements. It enables the pavement to act as a composite structure, thus reducing tensile stresses and allowing an ultra-thin PCC overlay to perform as intended. The Iowa Department of Transportation (Iowa DOT) UTW project (HR-559) initiated UTW in Iowa. The project is located on Iowa Highway 21 between Iowa Highway 212 and U.S. Highway 6 in Iowa County, near Belle Plaine, Iowa. The objective of this research was to investigate the interface bonding condition between an ultra-thin PCC overlay and an ACC base over time, considering the previously mentioned variables. This research lasted for five years, at which time it was extended an additional five years. The new phase of the project was initiated by removing cracked panels existing in the 2-inch thick PCC sections and replacing them with three inches of PCC. The project extension (TR 432) will provide an increased understanding of slab bonding conditions over a longer period, as well as knowledge regarding the behavior of the newly rehabilitated areas. In order to accomplish the goals of the project extension, Falling Weight Deflectometer (FWD) testing will continue to be conducted. Laboratory testing, field strain gage implementation, and coring will no longer be conducted. This report documents the planning and construction of the rehabilitation of HR 559 and the beginning of TR 432 during August of 1999.

Ultrathin Portland Cement Concrete Overlay Extended Evaluation, Interim Report, TR-432, 2002

The Iowa Department of Transportation (Iowa DOT) UTW Project (HR-559) initiated Ultra-Thin Whitetopping in Iowa. The project is located on Iowa Highway 21 between Iowa Highway 212 and U.S. Highway 6 in Iowa County, near Belle Plaine, Iowa. The above listed research project lasted for five years, and then was extended for another five year period. The new phase of the project (TR 432) was initiated by removing cracked panels existing in the 2-inch thick PCC sections and replacing them with three inches of PCC. The project extension provides an increased understanding of slab bonding conditions over a longer period, as well as knowledge regarding the behavior of the newly rehabilitated areas. This report documents the rehabilitation of the PCC patching of all fractured panels and several cracked panels, taking place in September of 2001.