Dowel Bar Optimization: Phases I and II, October 2001

America’s roadways are in serious need of repair. According to the American Society of Civil Engineers (ASCE), one-third of the nation’s roads are in poor or mediocre condition. ASCE has estimated that under these circumstances American drivers will sacrifice $5.8 billion and as many as 13,800 fatalities a year from 1999 to 2001 ( 1). A large factor in the deterioration of these roads is a result of how well the steel reinforcement transfers loads across the concrete slabs. Fabricating this reinforcement using a shape conducive to transferring these loads will help to aid in minimizing roadway damage. Load transfer within a series of concrete slabs takes place across the joints. For a typical concrete paved road, these joints are approximately 1/8-inch gaps between two adjacent slabs. Dowel bars are located at these joints and used to transfer load from one slab to its adjacent slabs. As long as the dowel bar is completely surrounded by concrete no problems will occur. However, when the hole starts to oblong a void space is created and difficulties can arise. This void space is formed due to a stress concentration where the dowel contacts the concrete. Over time, the repeated process of traffic traveling over the joint crushes the concrete surrounding the dowel bar and causes a void in the concrete. This void inhibits the dowel’s ability to effectively transfer load across the joint. Furthermore, this void gives water and other particles a place to collect that will eventually corrode and potentially bind or lock the joint so that no thermal expansion is allowed. Once there is no longer load transferred across the joint, the load is transferred to the foundation and differential settlement of the adjacent slabs will occur.

Assessment of Dowel Bar Research, August 2002

This report presents the latest technological gaps in dowel bar research based upon completed and ongoing dowel bar research from across the nation. In order to obtain this collection of information about dowel bars, a search was conducted on a nationwide level. The technological gaps and duplications of the research were then determined. In addition, this report also provides a brief annotated bibliography of all sources used to determine the gaps in technology and knowledge for dowel bar and alternative dowel bar topics as applied to highway pavements.

Long-term Plan for Concrete Pavement Research and Technology: The CP Road Map, November 2004, Volume 1 of 2

An Iowa State University–led team facilitated development of the CP Road Map. They developed a database of existing research. They gathered input, face to face, from the highway community. They identified gaps in research that became the basis for problem statements, which they organized into a cohesive, strategic research plan.

Long-term Plan for Concrete Pavement Research and Technology: The CP Road Map, November 2004, Volume 2 of 2

An Iowa State University–led team facilitated development of the CP Road Map. They developed a database of existing research. They gathered input, face to face, from the highway community. They identified gaps in research that became the basis for problem statements, which they organized into a cohesive, strategic research plan.

Long-term Plan for Concrete Pavement Research and Technology: The CP Road Map, November 2004

An Iowa State University–led team facilitated development of the CP Road Map. They developed a database of existing research. They gathered input, face to face, from the highway community. They identified gaps in research that became the basis for problem statements, which they organized into a cohesive, strategic research plan.

Dowel Bar Optimization: Phases I and II, October 2001

America’s roadways are in serious need of repair. According to the American Society of Civil Engineers (ASCE), one-third of the nation’s roads are in poor or mediocre condition (1). ASCE has estimated that under these circumstances American drivers will sacrifice $5.8 billion and as many as 13,800 fatalities a year from 1999 to 2001 ( 1). A large factor in the deterioration of these roads is a result of how well the steel reinforcement transfers loads across the concrete slabs. Fabricating this reinforcement using a shape conducive to transferring these loads will help to aid in minimizing roadway damage. Load transfer within a series of concrete slabs takes place across the joints. For a typical concrete paved road, these joints are approximately 1/8-inch gaps between two adjacent slabs. Dowel bars are located at these joints and used to transfer load from one slab to its adjacent slabs. As long as the dowel bar is completely surrounded by concrete no problems will occur. However, when the hole starts to oblong a void space is created and difficulties can arise. This void space is formed due to a stress concentration where the dowel contacts the concrete. Over time, the repeated process of traffic traveling over the joint crushes the concrete surrounding the dowel bar and causes a void in the concrete. This void inhibits the dowel’s ability to effectively transfer load across the joint. Furthermore, this void gives water and other particles a place to collect that will eventually corrode and potentially bind or lock the joint so that no thermal expansion is allowed. Once there is no longer load transferred across the joint, the load is transferred to the foundation and differential settlement of the adjacent slabs will occur.

Material and Construction Optimization for Prevention of Premature Pavement Distress in PCC Pavements, September 2004

The chemistry of today’s concrete mixture designs is complicated by many variables, including multiple sources of aggregate and cements and a plethora of sometimes incompatible mineral and chemical admixtures. Concrete paving has undergone significant changes in recent years as new materials have been introduced into concrete mixtures. Supplementary cementitious materials such as fly ash and ground granulated blast furnace slag are now regularly used. In addition, many new admixtures that were not even available a few years ago now have widespread usage. Adding to the complexity are construction variables such as weather, mix delivery times, finishing practices, and pavement opening schedules. Mixture materials, mix design, and pavement construction are not isolated steps in the concrete paving process. Each affects and is affected by the other in ways that determine overall pavement quality and long-term performance. Equipment and procedures commonly used to test concrete materials and concrete pavements have not changed in decades, leaving serious gaps in our ability to understand and control the factors that determine concrete durability. The concrete paving community needs tests that will adequately characterize the materials, predict interactions, and monitor the properties of the concrete.

Strategic Plan for Improved Concrete Pavement Surface Characteristics, July 2006

Surface characteristics represent a critical issue facing pavement owners and the concrete paving industry. The traveling public has come to expect smoother, quieter, and better drained pavements, all without compromising safety. The overall surface characteristics issues is extremely complex since all pavement surface characteristics properties, including texture, noise, friction, splash/spray, rolling resistance, reflectivity/illuminance, and smoothness, are complexly related. The following needs and gaps related to achieving desired pavement surface characteristics need to be addressed: determined how changes in one surface characteristic affect, either beneficially or detrimentally, other characteristics of the pavement, determine the long-term surface and acoustic durability of different textures, and develop, evaluate, and standardize new data collection and analysis tools. It is clear that an overall strategic and coordinated research approach to the problem must be developed and pursued to address these needs and gaps.

Developing a Simple and Rapid Test for Monitoring the Heat Evolution of Concrete Mixtures for Both Laboratory and Field Applications, January 2006

Various test methods exist for measuring heat of cement hydration; however, most current methods require expensive equipment, complex testing procedures, and/or extensive time, thus not being suitable for field application. The objectives of this research are to identify, develop, and evaluate a standard test procedure for characterization and quality control of pavement concrete mixtures using a calorimetry technique. This research project has three phases. Phase I was designed to identify the user needs, including performance requirements and precision and bias limits, and to synthesize existing test methods for monitoring the heat of hydration, including device types, configurations, test procedures, measurements, advantages, disadvantages, applications, and accuracy. Phase II was designed to conduct experimental work to evaluate the calorimetry equipment recommended from the Phase I study and to develop a standard test procedure for using the equipment and interpreting the test results. Phase II also includes the development of models and computer programs for prediction of concrete pavement performance based on the characteristics of heat evolution curves. Phase III was designed to study for further development of a much simpler, inexpensive calorimeter for field concrete. In this report, the results from the Phase I study are presented, the plan for the Phase II study is described, and the recommendations for Phase III study are outlined. Phase I has been completed through three major activities: (1) collecting input and advice from the members of the project Technical Working Group (TWG), (2) conducting a literature survey, and (3) performing trials at the CP Tech Center’s research lab. The research results indicate that in addition to predicting maturity/strength, concrete heat evolution test results can also be used for (1) forecasting concrete setting time, (2) specifying curing period, (3) estimating risk of thermal cracking, (4) assessing pavement sawing/finishing time, (5) characterizing cement features, (6) identifying incompatibility of cementitious materials, (7) verifying concrete mix proportions, and (8) selecting materials and/or mix designs for given environmental conditions. Besides concrete materials and mix proportions, the configuration of the calorimeter device, sample size, mixing procedure, and testing environment (temperature) also have significant influences on features of concrete heat evolution process. The research team has found that although various calorimeter tests have been conducted for assorted purposes and the potential uses of calorimeter tests are clear, there is no consensus on how to utilize the heat evolution curves to characterize concrete materials and how to effectively relate the characteristics of heat evolution curves to concrete pavement performance. The goal of the Phase II study is to close these gaps.

Infrastructure and Transportation Task Force Report, August 2008

The Rebuild Iowa Infrastructure and Transportation Task Force is acutely aware of the critical role infrastructure plays in Iowa’s communities, the lives of the residents, and the economic well-being of the state. With encouragement to the Rebuild Iowa Advisory Commission (RIAC) for its consideration of great need for infrastructure and transportation repairs, the Task Force provides its assessment and recommendations. As the RIAC fulfills its obligations to guide the recovery and reconstruction in Iowa, infrastructure and transportation must be recognized for its impact on all Iowans. The tornadoes, storms, and floods were devastating to infrastructure and transportation systems across the state. The damage did not distinguish between privately-owned and public assets. The significance of the damage emerges further with the magnitude of the damage estimates. Infrastructure includes components that some might initially overlook, such as communication systems, landfills, and water treatment. The miles of damaged roads and bridges are more evident to many Iowans. Given the reliance on infrastructure systems, many repairs are already underway, though gaps have emerged in the funding for repairs to certain infrastructure systems.

Affordable Housing in Iowa: Meeting New Challenges, 2007

Iowa faces a signifi cant challenge over the next decade. In the words of a recent report, “The state faces the danger of worker and skill gaps that could undermine its businesses, erode the earning power of its workers, and slow its economic growth.” (Iowa Works Campaign, 2006) Iowa’s economic and demographic stability depends on attracting new immigrants and slowing the departure of residents. Eroding housing affordability and quality will make this more difficult. Housing alone cannot solve the problem, but it must be part of the solution. This study examines trends in the state’s major housing markets, analyzes the achievements of housing programs in the recent past, and incorporates input from more than 80 housing experts across the state. The second part of this study (included on the attached CD) analyzes housing’s impact on the economy. We developed three major policy recommendations.

Affordable Housing in Iowa: Meeting New Challenges, 2007

Iowa faces a significant challenge over the next decade. In the words of a recent report, “The state faces the danger of worker and skill gaps that could undermine its businesses, erode the earning power of its workers, and slow its economic growth.” (Iowa Works Campaign, 2006) Iowa’s economic and demographic stability depends on attracting new immigrants and slowing the departure of residents. Eroding housing affordability and quality will make this more difficult. Housing alone cannot solve the problem, but it must be part of the solution. This study examines trends in the state’s major housing markets, analyzes the achievements of housing programs in the recent past, and incorporates input from more than 80 housing experts across the state. The second part of this study (included on the attached CD) analyzes housing’s impact on the economy. We developed three major policy recommendations.

Evaluating Direct and Indirect Economic Outcomes of the 2008 Iowa Weather‐Related Disasters

This research seeks to fill some of the gaps in understanding the local, regional, and statewide economic consequences of the disasters of 2008. This report evaluates sets of population, unemployment, employment, business firms, and trade patterns over time in an attempt to discern the household consumption and business productivity disruptions caused by the weather disasters of 2008.

Supplement Information to the August 2008 Infrastructure and Transportation Task Force Report, August 2008

The Rebuild Iowa Infrastructure and Transportation Task Force is acutely aware of the critical role infrastructure plays in Iowa’s communities, the lives of the residents, and the economic well-being of the state. With encouragement to the Rebuild Iowa Advisory Commission (RIAC) for its consideration of great need for infrastructure and transportation repairs, the Task Force provides its assessment and recommendations. As the RIAC fulfills its obligations to guide the recovery and reconstruction in Iowa, infrastructure and transportation must be recognized for its impact on all Iowans. The tornadoes, storms, and floods were devastating to infrastructure and transportation systems across the state. The damage did not distinguish between privately-owned and public assets. The significance of the damage emerges further with the magnitude of the damage estimates. Infrastructure includes components that some might initially overlook, such as communication systems, landfills, and water treatment. The miles of damaged roads and bridges are more evident to many Iowans. Given the reliance on infrastructure systems, many repairs are already underway, though gaps have emerged in the funding for repairs to certain infrastructure systems. Supplement Information to the August 2008

Bureau of HIV, STD, & Hepatitis Quarterly Newsletter, January — March 2011, Vol. 1

This newsletter of the Bureau of HIV, STD, and Hepatitis. The idea of the newsletter was to improve communication between the bureau and those who are delivering HIV, STD, and hepatitis prevention, surveillance, and care programs across the state. More specifically, we would like to use the newsletter as a vehicle through which we can improve prevention and care services in Iowa. We will try to do this by describing the services and programs we fund, and by reflecting on data that we collect to help prevention and care providers make decisions on policies, unmet needs, and service gaps in the state. At the same time, we will try to keep you abreast of new programs, resources, and policies that may affect the work that you do and the lives of those living with or affected by HIV, STDs, and viral hepatitis.