Improvement of Longitudinal Joints in Asphalt Pavement, HR-215, 1987

Research is reported which attempted to identify construction procedures that will provide an improved centerline joint on asphalt concrete pavements. Various construction procedures and their evaluation are described. Core densities were made and visual inspections were made 3 years after construction. Center cracking was measured at 4, 5, and 6 years. The only procedure to rank the same when comparing cracking and density (delete the 1:1 slope shoe on the edge) is described. This procedure had the highest average density and also the least cracking through 1985. This method provided the best performance for 4 years after construction and involved the removal of the 1:1 slope shoe from the paver when placing the surface course. This method had 9.0% cracked after 4 years and 100% cracked after 6 years of service.

Healthy Iowans 2010 Mid-Course Revision, July 2005

In the past century, public health has been credited with adding 25 years to life expectancy by contributing to the decline in illness and injury. Progress has been made, for example, in smoking reduction, infectious disease, and motor vehicle and workplace injuries. Besides its focus on traditional concerns such as clean water and safe food, public health is adapting to meet emerging health problems. Particular troublesome are health threats to youth: teenage pregnancies, violence, substance abuse, sexually transmitted diseases, and other conditions associated with high-risk behaviors. These threats add to burgeoning health care costs. A conservative estimate of $69 billion in medical spending could be averted through the impact of public health strategies aimed at heart disease, stroke, fatal and nonfatal occupational injuries, motor vehicle-related injuries, low birth weight, and violence. These strategies require the collaboration of many groups in the public and private sectors. Collaboration is the bedrock of public health and Healthy Iowans planning. At the core of Healthy Iowans 2000 and its successor, Healthy Iowans 2010, is the idea that all Iowans benefit when stakeholders decide on disease prevention and health promotion strategies and agree to work together on them. These strategies can improve the quality of life and hold down health care costs. The payoff for health promotion and disease prevention is not immediate, but it has long-lasting benefits. The Iowa plan is a companion to the national plan, Healthy People 2010. An initiative to improve the health of Americans, the national plan is the driving force for federal resource allocation for disease prevention and health promotion. The state plan is used in the same way. Both plans have received broad support from Republican and Democratic administrations. Community planners are using the state plan to help assess health needs and craft health improvement plans. Healthy Iowans 2010 was written at an unusual point in history – a new decade, a new century, a new millennium. The introduction was optimistic. “The 21st century,” it says, “promises to add life as well as years through improved health habits coupled with medical advances. Scientists have suggested that if these changes occur, the definition of adulthood will also change. An extraordinary number of people will live fuller, more active lives beyond that expected in the late 20th century.” At the same time, the country has spawned a new generation of health hazards. According to Dr. William Dietz of the Centers for Disease Control and Prevention (CDC), it has replaced “the diseases of deficiency with diseases of excess” (Newsweek, August 2, 1999). New threats, such as childhood overweight, can reverse progress made in the last century. This demands concerted action.

Charting Our Own Course: Today’s Challenges, Tomorrow’s Opportunities, December 2008

The Office of Energy Independence presents Iowa’s second annual energy independence plan, which highlights accomplishments achieved thus far and makes recommendations for the coming year. This plan shows that Iowa has made significant progress in building the foundation for reaching energy independence in just the past year. Continued investment and further efforts will enable Iowa to push toward even greater advances, while creating new jobs and diversifying local economies. With those aims in mind, the state has been investing extensively in the new energy economy. One important example is the Iowa Power Fund, an annual appropriation from the Iowa General Assembly administered by the Office of Energy Independence. In less than one year, the Office has received more than 160 project applications totaling more than $308 million in requests. The projects approved thus far will help advance Iowa’s wind and solar industries, foster new energy efficiency practices, and develop the bio fuels industry for a more economically and environmentally sustainable future. Iowa’s position as a leader in the new energy economy is dependent on the success of the Power Fund, and on the success of this plan. This plan clearly states that Iowa must boldly pursue a strong position in the emerging energy economy worldwide.

An Integrated Study of Pervious Concrete Mixture Design for Wearing Course Applications, July 2011

This report presents the results of the largest and most comprehensive study to date on portland cement pervious concrete (PCPC). It is designed to be widely accessible and easily applied by designers, producers, contractors, and owners. The project was designed to begin with pervious concrete best practices and then to address the unanswered questions in a systematic fashion to allow a successful overlay project. Consequently, the first portion of the integrated project involved a combination of fundamental material property investigations, test method development, and addressing constructability issues before actual construction could take place. The second portion of the project involved actual construction and long-term testing before reporting successes, failures, and lessons learned. The results of the studies conducted show that a pervious concrete overlay can be designed, constructed, operated, and maintained. A pervious concrete overlay has several inherent advantages, including reduced splash and spray and reduced hydroplaning potential, as well as being a very quiet pavement. The good performance of this overlay in a particularly harsh freeze-thaw climate, Minnesota, shows pervious concrete is durable and can be successfully used in freeze-thaw climates with truck traffic and heavy snow plowing.

Guide Specification for Highway Construction Texturing Concrete Pavement for Reduced Tire/Pavement Noise using Longitudinal Tining, March 1, 2011

This document provides language that can be used by an Owner-Agency to develop materials and construction specifications with the objective of reducing tire/pavement noise. While the practices described herein are largely prescriptive, they have been demonstrated to increase the likelihood of constructing a durable, quieter concrete surface. Guidance is provided herein for texturing the concrete surface since texture geometry has a paramount effect on tire/pavement noise. Guidance for curing is also provided to improve strength and durability of the surface mortar, and thus to improve texture durability.

Final Report Factors Influencing Stability of Granular Base Course Mixes

To evaluate the various factors influencing the stability of granular base course mixes, three primary goals were included in the project: (1) determination of a suitable and realistic laboratory method of compaction; (2) effect of gradation, density and mineralogy of the fines on sheara ing strength; and (3) possible improvement of the shear strength with organic and inorganic chemical stabilization additives.

An Investigation of the Interstate 80 Rutting in Adair County, October 1983

This investigation was initiated to determine the causes of a rutting problem that occurred on Interstate 80 in Adair County. 1-80 from Iowa 25 to the Dallas County line was opened to traffic in November, 1960. The original pavement consisted of 4-1/2" of asphalt cement concrete over 12" of rolled stone base and 12" of granular subbase. A 5-1/2" overlay of asphalt cement concrete was placed in 1964. In 1970-1972, the roadway was resurfaced with 3" of asphalt cement concrete. In 1982, an asphalt cement concrete inlay, designed for a 10-year life, was placed in the eastbound lane. The mix designs for all courses met or exceeded all current criteria being used to formulate job mixes. Field construction reports indicate .that asphalt usage, densities, field voids and filler bitumen determinations were well within specification limits on a very consistent basis. Field laboratory reports indicate that laboratory voids for the base courses were within the prescribed limits for the base course and below the prescribed limits for the surface course. Instructional memorandums do indicate that extreme caution should be exercised when the voids are at or near the lower limits and traffic is not minimal. There is also a provision that provides for field voids controlling when there is a conflict between laboratory voids and field voids. It appears that contract documents do not adequately address the directions that must be taken when this conflict arises since it can readily be shown that laboratory voids must be in the very low or dangerous range if field voids are to be kept below the maximum limit under the current density specifications. A rut depth survey of January, 1983, identified little or no rutting on this section of roadway. Cross sections obtained in October, 1983, identified rutting which ranged from 0 to 0.9" with a general trend of the rutting to increase from a value of approximately 0.3" at MP 88 to a rut depth of 0.7" at MP 98. No areas of significant rutting were identified in the inside lane. Structural evaluation with the Road Rater indicated adequate structural capacity and also indicated that the longitudinal subdrains were functioning properly to provide adequate soil support values. Two pavement sections taken from the driving lane indicated very little distortion in the lower 7" base course. Essentially all of the distortion had occurred in the upper 2" base course and the 1..;1/2" surface course. Analysis of cores taken from this section of Interstate 80 indicated very little densification of either the surface or the upper or lower base courses. The asphalt cement content of both the Type B base courses and the Type A surface course were substantially higher than the intended asphalt cement content. The only explanation for this is that the salvaged material contained a greater percent of asphalt cement than initial extractions indicated. The penetration and viscosity of the blend of new asphalt cement and the asphalt cement recovered from the salvaged material were relatively close to that intended for this project. The 1983 ambient temperatures were extremely high from June 20 through September 10. The rutting is a result of a combination of adverse factors including, (1) high asphalt content, (2) the difference between laboratory and field voids, (3) lack of intermediate sized crushed particles, (4) high ambient temperatures. The high asphalt content in the 2" upper base course produced an asphalt concrete mix that did not exhibit satisfactory resistance to deformation from heavy loading. The majority of the rutting resulted from distortion of the 2" upper base lift. Heater planing is recommended as an interim corrective action. Further recommendation is to design for a 20-year alternative by removing 2-1/2" of material from the driving lane by milling and replacing with 2-1/2" of asphalt concrete with improved stability. This would be .followed by placing 1-1/2" of high quality resurfacing on the entire roadway. Other recommendations include improved density and stability requirements for asphalt concrete on high traffic roadways.

Your Course to College, 2012-13 Edition

Who better to give advice to a future college student, like you, than current college students! Look throughout this guide for high school, college, and career advice from current students at Iowa’s colleges and universities!

Your Course to College, 2011-12 Edition

We are a state agency dedicated to serving Iowa students by awarding close to 25,000 scholarships and grants each year. You can learn about federal and state college financial aid programs through Iowa College Aid’s valuable information resources. Visit Iowa College Aid’s website at www.IowaCollegeAid.gov or call the Information Service Center at 877-272-4456 for detailed information regarding our programs and services. You can also find us on Facebook, follow us on Twitter, and view our videos on YouTube to help you before, during and after college.

Your Course to College, 2010-11 Edition

This document is produced for the citizens of Iowa from Iowa College Aid for college and career informational purposes. It includes college and career search information, financial aid information and Iowa college and university information for the 2010-11 academic year.

Your Course to College, 2009-10 Edition

This document is produced for the citizens of Iowa from Iowa College Aid for college and career informational purposes. It includes college and career search information, financial aid information and Iowa college and university information for the 2009-10 academic year.

Use of Longitudinal Subdrains in the 3R Program, HR-509, Progress Report #2, 1981

The main consideration for base construction under the pavement, in the design of Iowa's interstate, was structural capacity. The material was dense graded with the aim of supporting the pavement and distributing the load as it is transferred to the underlying grade. The drainage characteristics of the base was apparently not given adequate consideration. On jointed portland cement concrete pavement, the water that is trapped immediately beneath the pavement causes severe problems. The traffic causes rapid movement of the water resulting in the hydraulic pressures or "pumping" (movement and redeposit of base fine material), further resulting in faulting between individual slabs. The objective of this evaluation is to determine if longitudinal subdrains are effective in preventing or reducing pumping, faulting and related deterioration. Results suggest that, based upon the flow from the outlets observed during periodic checks and evidence of water flow at the outlets, it appears that to date the subdrains are effective in draining the subbase and subgrade. Because of the limited data available at this time, however, the pavement condition and faulting results are inconclusive.

Asphalt Cement Concrete Longitudinal Joint Adhesive Crafco PN 34524 (Iowa DOT New Product C-98-7), HR-2084, 2000

The joint between two lanes of asphalt pavement is often the first area of a roadway which shows signs of deterioration and requires maintenance. As the final lift of hot asphalt is being placed in a construction project, it is being forced p against the adjoining lane of cold asphalt, forming the longitudinal joint. The mating of the two lanes, to form a high quality seal, is often not fully successful and later results in premature stripping or raveling as water enters the unsealed joint. The application of a hot poured rubberized asphaltic joint sealant along the joint face in the final stage of construction should help to form a watertight joint seal. A new product, especially formulated for the longitudinal joint in asphalt pavements was proposed to improve joint sealing. The following describes the experimental application of the new product, Crafco, PN 34524.

Metric Short Course for the Office of Bridges and Structures, HR-378, 1995

This metric short course was developed in response to a request from the Office of Bridges and Structures to assist in the training of engineers in the use of metric units of measure which will be required in all highway designs and construction after September 30, 1996 (CFR Presidential Executive Order No. 12770). The course notes which are contained in this report, were developed for a half-day course. The course contains a brief review of metrication in the U.S., metric units, prefixes, symbols, basic conversions, etc. The unique part of the course is that it presents several typical bridge calculations (such as capacity of reinforced concrete compression members, strength of pile caps, etc.) worked two ways: inch-pound units throughout with end conversion to metric and initial hard conversion to metric with metric units throughout. Comparisons of partial results and final results (obtained by working the problems the two ways) are made for each of the example problems.

Dense Concrete Layer as Top Course of Bridge Deck Construction, HR-502, 1990

The use of deicing salts in this part of the country is a necessity to remove ice from our bridges. The use of these salts has always been a problem since the chloride-ions penetrate the concrete and reach the steel and cause corrosion which eventually cause deterioration of both the steel and concrete. One method used to try to prevent this from happening was to apply a waterproof membrane to the concrete after it was placed. This method did help, but was not cost effective as the longevity of the membrane system was of relatively short duration. For this reason, this research project was initiated. After the original deck was placed a second layer of concrete about 1 1/2" thick was placed on top. Biennial evaluation of the decks included testing for delaminations and steel corrosion. Cores were also obtained for a chloride analysis. Testing and observations showed the two-layer bridge deck to be effective in preventing corrosion. Since the time this project was initiated, epoxy steel has been introduced and is a cost effective way to protect the steel from corrosion.