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Bridges Designed for Minimum Maintenance, TR-791, 2025
No full textService-life based designs of highway bridges have gained significant interest from state DOTs in recent years. The primary purpose of these efforts is to provide durability-based designs for bridges and bridge elements that require minimal maintenance during the targeted service life of the structure. This is achieved by defining different target service lives for bridge design with the assumption that a longer target service life will result in a longer period with no or minimal maintenance. While the importance of durability-based design is highlighted in the report, which aims to achieve varying levels of target service lives that change based on the importance or the criticality of the bridge, the study acknowledges that most common bridges could be replaced due to functional improvements
rather than reaching the end of their service life. Target service lives of 75 years (Normal), 100 years (Enhanced), and 125 years (Maximum) are considered in this report. The study focuses on identifying common types of bridge deterioration and maintenance activities, developing design recommendations suited to various traffic conditions and exposures, and validating the performance and cost-effectiveness of these designs through service life analysis. The report also discusses the challenges of predicting long-term degradation mechanisms and exposure conditions, and the importance of preventive maintenance strategies to prolong bridge life.
Practical recommendations are presented for the considered bridge elements to achieve the different target service lives using economical design considerations. The immediate benefit of this research is implementing cost-effective bridge designs that require little to no maintenance, thereby reducing long-term costs and improving the overall performance of the transportation system in Iowa. The findings of this study could also be used by Iowa DOT to develop a guide for service life design of Iowa bridges
Beneficial Use of Iowa Waste Ashes in Concrete through Carbon Sequestration, TR-807, 2025
No full textA significant amount of waste ash in the United States does not meet the necessary specifications for construction and other uses, and power plants are searching for a way to dispose of surplus waste ashes.
To address this issue, this research aimed to treat waste ashes using CO2 injection in order to modify their properties and enable their beneficial use in concrete. The main tasks of the study were to (1) optimize the carbon treatment procedure (pressure, moisture, and time) for the selected waste ashes, (2) determine the effects of the carbon treatment on the properties of the ashes (surface chemistry, morphology, pore structure, etc.), (3) evaluate the effects of carbon-treated ashes on the properties of cement composites such as paste and mortar (set time, flowability, hydration, strength, etc.), and (4) quantify CO2 sequestration and assess the benefit-to-cost potential of the carbon-curing treatment. Findings indicate that certain types of waste ashes can increase the decarbonation of cement and concrete providing a use for the waste ashes and promoting sustainability
2024 Early Childhood Iowa (ECI) Annual Report, January 2025
No full textEarly Childhood Iowa (ECI) is a statewide initiative housed within the Iowa Department of Health and Human Services (HHS) that unites public and private agencies, organizations, and stakeholders under one common vision, “Every child, beginning at birth, will be healthy and successful.
Report on Dickinson County, Iowa for the year ended June 30, 2024
Get PDFReport on Dickinson County, Iowa for the year ended June 30, 202
Agreed-upon procedures report on the City of Farley, Iowa for the period July 1, 2022 through June 30, 2023
No full textAgreed-upon procedures report on the City of Farley, Iowa for the period July 1, 2022 through June 30, 202
Research Solutions: Using Concrete Grinding Residue to Stabilize Road Shoulders, TR-764, 2025
Get PDFUnpaved gravel shoulders and embankments with little or no vegetation are vulnerable to erosion from wind and rain as well as from wind whip caused by traffic. Because strength and stiffness are critical design criteria for roadway shoulders and embankments, lime, portland cement, and other additives are commonly used to stabilize soils in these areas. While the use of waste byproducts such as CGR can provide an economical and sustainable alternative for stabilizing roadway
embankments and shoulder materials, little research and no full-scale field implementation efforts have been undertaken to assess the use of CGR as a soil amendment for mitigating erosivity. The objective of this study is to evaluate the potential use of concrete grinding residue (CGR) as a soil amendment for stabilizing roadway shoulders and embankments
Agreed-upon procedures report on the City of Raymond, Iowa for the period July 1, 2022 through June 30, 2023
No full textAgreed-upon procedures report on the City of Raymond, Iowa for the period July 1, 2022 through June 30, 202
Agreed-upon procedures report on the City of New Sharon, Iowa for the period July 1, 2023 through June 30, 2024
Get PDFAgreed-upon procedures report on the City of New Sharon, Iowa for the period July 1, 2023 through June 30, 202
Report of the ADLM Counties Environmental Public Health Agency as of and for the year ended June 30, 2024
Get PDFReport of the ADLM Counties Environmental Public Health Agency as of and for the year ended June 30, 202
