Determine Initial Cause for Current Premature Portland Cement Concrete Pavement Deterioration Final Report, 2000

A detailed investigation has been conducted on core samples taken from 17 portland cement concrete pavements located in Iowa. The goal of the investigation was to help to clarify the root cause of the premature deterioration problem that has become evident since the early 1990s. Laboratory experiments were also conducted to evaluate how cement composition, mixing time, and admixtures could have influenced the occurrence of premature deterioration. The cements used in this study were selected in an attempt to cover the main compositional parameters pertinent to the construction industry in Iowa. The hardened air content determinations conducted during this study indicated that the pavements that exhibited premature deterioration often contained poor to marginal entrained-air void systems. In addition, petrographic studies indicated that sometimes the entrained-air void system had been marginal after mixing and placement of the pavement slab, while in other instances a marginal to adequate entrained-air void system had been filled with ettringite. The filling was most probably accelerated because of shrinkage cracking at the surface of the concrete pavements. The results of this study suggest that the durability—more sciecifically, the frost resistance—of the concrete pavements should be less than anticipated during the design stage of the pavements. Construction practices played a significant role in the premature deterioration problem. The pavements that exhibited premature distress also exhibited features that suggested poor mixing and poor control of aggregate grading. Segregation was very common in the cores extracted from the pavements that exhibited premature distress. This suggests that the vibrators on the paver were used to overcome a workability problem. Entrained-air voids formed in concrete mixtures experiencing these types of problems normally tend to be extremely coarse, and hence they can easily be lost during the paving process. This tends to leave the pavement with a low air content and a poor distribution of air voids. All of these features were consistent with a premature stiffening problem that drastically influenced the ability of the contractor to place the concrete mixture. Laboratory studies conducted during this project indicated that most premature stiffening problems can be directly attributed to the portland cement used on the project. The admixtures (class C fly ash and water reducer) tended to have only a minor influence on the premature stiffening problem when they were used at the dosage rates described in this study.

Barriers to Employment, March 2001

During the last five years, Iowa has experienced a shortage of workers and will continue to feel the impact of a short labor supply. As the state prepares to reverse this trend of a declining population, attracting immigrants and refugees has great potential. In addition, released preliminary reports from the 2000 Census are reporting growth of the Latino population in several Iowa counties. This survey was conducted as a way to supplement the information collected about the Latino population by the State Public Policy Group in 1999, Snapshot in Time: A clear view of the importance, value and impacts of the Latino population in central Iowa. (Una Foto Actual de la Comunicad Latina: Un panoramaclaro de la importancia, del valor, y de los impactos de la población Latina en el área central de Iowa.) Although this survey was enlightening, it was broad in scope. It was the goal of the agency to collect more specific data regarding workforce needs and barriers that the Latino population encounter in the State of Iowa. Although it was the desire to broaden the scope of the previous survey, it should be noted that the survey samples were not identical. But it is recognized that because the Latino population within the state is small, some of the respondents could have participated in both surveys. We were also hoping to benefit from the extensive work conducted by SPPG within the community as a way to increase the response rate for this survey. This executive summary highlights some of the most significant findings from the survey of Latinos residing in Central Iowa. This analysis centers on the impact the Latino population can have in filling the labor shortages and how Iowa can best embrace the new Iowan. In addition, some of the key findings could offer insight into removing unnecessary barriers that prevent immigrants from utilizing valuable work skills as they integrate into the workforce. This information may be insightful to community leaders and employers who want to welcome new immigrants into their community. The following diagram collected from the 2000 Census illustrates the percentage of Latinos residing in the state.

Gift of Peace of Mind-The For yourself For your Family,

The purpose of this booklet is to educate the public about advance directives. By doing so, we hope to increase the use of advance directives, as well as the quality and accuracy of the documents themselves. The reader is led through a series of steps that ultimately lead to filling out the advance directive documents in an informed manner.

Gift of Peace of Mind-The For yourself For your Family, 2000, Large Print Edition

The purpose of this booklet is to educate the public about advance directives. By doing so, we hope to increase the use of advance directives, as well as the quality and accuracy of the documents themselves. The reader is led through a series of steps that ultimately lead to filling out the advance directive documents in an informed manner.

Secondary Accident Data Fusion for Assessing Long-Term Performance of Transportation Systems, 2007

Secondary accident statistics can be useful for studying the impact of traffic incident management strategies. An easy-to-implement methodology is presented for classifying secondary accidents using data fusion of a police accident database with intranet incident reports. A current method for classifying secondary accidents uses a static threshold that represents the spatial and temporal region of influence of the primary accident, such as two miles and one hour. An accident is considered secondary if it occurs upstream from the primary accident and is within the duration and queue of the primary accident. However, using the static threshold may result in both false positives and negatives because accident queues are constantly varying. The methodology presented in this report seeks to improve upon this existing method by making the threshold dynamic. An incident progression curve is used to mark the end of the queue throughout the entire incident. Four steps in the development of incident progression curves are described. Step one is the processing of intranet incident reports. Step two is the filling in of incomplete incident reports. Step three is the nonlinear regression of incident progression curves. Step four is the merging of individual incident progression curves into one master curve. To illustrate this methodology, 5,514 accidents from Missouri freeways were analyzed. The results show that secondary accidents identified by dynamic versus static thresholds can differ by more than 30%.

Competency Guide, 2006

On the Human Resource Management Roadmap (see page 7 of the State of Iowa Workforce Planning Guide, February 2006) there is a bar that crosses all four phases of human resource management. That section indicates that competencies are an integral part of the entire employment cycle. Competencies describe job requirements, which means they lay out the expectations for the job incumbent as well as the supervisor as they relate to planning for the job, recruiting and filling the job, developing the incumbent’s skills, assessing the incumbent’s performance, and finally, determining how those same competencies relate, if at all, to refilling the position when it becomes vacant in the future.

Business Sphere, Vol. 21, no.3

Iowa may be known for some of the world’s most fertile cropland, but in recent years, we’ve become fertile ground for rapid growth in information technology as well. From the recent “plug-in” of Google’s $600-million Council Bluffs data center to Microsoft’s planned half-billion-dollar West Des Moines expansion to IBM’s 1,300-job-creating expansion in Dubuque, technology leaders are finding Iowa a place to grow. And why not? Iowa has a supportive business climate and its infrastructure — physical and human — give our technology companies the competitive advantages that allow them to grow and prosper.

Business Sphere, Vol. 18, no.3

Iowa may be known for some of the world’s most fertile cropland, but in recent years, we’ve become fertile ground for rapid growth in information technology as well. From the recent “plug-in” of Google’s $600-million Council Bluffs data center to Microsoft’s planned half-billion-dollar West Des Moines expansion to IBM’s 1,300-job-creating expansion in Dubuque, technology leaders are finding Iowa a place to grow. And why not? Iowa has a supportive business climate and its infrastructure — physical and human — give our technology companies the competitive advantages that allow them to grow and prosper.

Business Sphere, Vol. 19, no.3

Iowa may be known for some of the world’s most fertile cropland, but in recent years, we’ve become fertile ground for rapid growth in information technology as well. From the recent “plug-in” of Google’s $600-million Council Bluffs data center to Microsoft’s planned half-billion-dollar West Des Moines expansion to IBM’s 1,300-job-creating expansion in Dubuque, technology leaders are finding Iowa a place to grow. And why not? Iowa has a supportive business climate and its infrastructure — physical and human — give our technology companies the competitive advantages that allow them to grow and prosper.

A LIBRARY IN THE MAKING: Pioneer History of the Territorial and State Library of Iowa,October 1912

The discovery of early manuscript reports of Territorial and State Librarians, buried in the mass of old official papers transferred from the several departments of State to the new Department of Archives in the Historical Building, has suggested the propriety of completing as far as possible, the historical record of Iowa's State Library, "from the earliest period to the present time." After a thorough research through the papers on file in the Archives Department, the published Journals and departmental reports in the State Library and documents and private papers loaned me by Mr. Newton R. Parvin, librarian of the Iowa Masonic Library, Cedar Rapids. I am now able to present the following historical sketch, Supplemented by the hitherto unpublished papers referred to this filling a gap in the history of a State institution which from very small beginnings has grown to large proportions and has made for itself a firm place in the respect and esteem of every citizen of Iowa.

Low-Cost Rural Surface Alternatives: Literature Review and Recommendations, TR-632, 2013

Freezing and thawing action induces damage to unbound gravel roads in Iowa resulting in maintenance costs for secondary road departments. Some approaches currently used by County Engineers to deal with this problem include temporarily spreading rock on the affected areas, lowering or improving drainage ditches, tiling, bridging the area with stone and geosynthetic covered by a top course of aggregate or gravel, coring boreholes and filling them with calcium chloride to melt lenses and provide drainage, and re-grading the crown to a slope of 4% to 6% to maximize spring drainage. However, most of these maintenance solutions are aimed at dealing with conditions after they occur. This study was tasked with identifying alternative approaches in the literature to mitigate the problem. An annotated bibliographic record of literature on the topic of frost-heave and thaw-weakening of gravel roads was generated and organized by topic, and all documents were assessed in terms of a suitable rating for mitigating the problem in Iowa. Over 300 technical articles were collected and selected down to about 150 relevant articles for a full assessment. The documents collected have been organized in an electronic database, which can be used as a tool by practitioners to search for information regarding the various repair and mitigation solutions, measurement technologies, and experiences that have been documented by selected domestic and international researchers and practitioners. Out of the 150+ articles, 71 articles were ranked as highly applicable to conditions in Iowa. The primary mitigation methods identified in this study included chemical and mechanical stabilization; scarification, blending, and recompaction; removal and replacement; separation, and reinforcement; geogrids and cellular confinement; drainage control and capillary barriers, and use of alternative materials. It is recommended that demonstration research projects be established to examine a range of construction methods and materials for treating granular surfaced roadways to mitigate frost-heave and thaw-weakening problems. Preliminary frost-susceptibility test results from ASTM D5916 are included for a range of Iowa materials.

Reduction of Concrete Deterioration by Ettringite Using Crystal Growth Inhibition Techniques, TR-431, 2001

Many researchers have concluded that secondary or delayed ettringite is responsible for serious premature deterioration of concrete highways. In some poorly performing Iowa concretes, ettringite is the most common secondary mineral but its role in premature deterioration is uncertain since some researchers still maintain that secondary ettringite does not itself cause deterioration. The current research project was designed to determine experimentally if it is possible to reduce secondary ettringite formation in concrete by treating the concrete with commercial crystallization inhibitor chemicals. The hypothesis is such that if the amount of ettringite is reduced, there will also be a concomitant reduction of concrete expansion and cracking. If both ettringite formation and deterioration are simultaneously reduced, then the case for ettringite induced expansion/cracking is strengthened. The experiment used four commercial inhibitors - two phosphonates, a polyacrylic acid, and a phosphate ester. Concrete blocks were subjected to continuous immersion, wet/dry and freeze/thaw cycling in sodium sulfate solutions and in sulfate solutions containing an inhibitor. The two phosphonate inhibitors, Dequest 2060 and Dequest 2010, manufactured by Monsanto Co., were effective in reducing ettringite nucleation and growth in concrete. Two other inhibitors, Good-rite K752 and Wayhib S were somewhat effective, but less so than the two phosphonates. Rapid experiments with solution growth inhibition of ettringite without the presence of concrete phases were used to explore the mechanisms of inhibition of this mineral. Reduction of new ettringite formation in concrete blocks also reduced expansion and cracking of the blocks. This relationship clearly links concrete expansion with this mineral - a conclusion that some research workers have disputed despite theoretical arguments for such a relationship and despite numerous observations of ettringite mineralization in prematurely deteriorated concrete highways. Secondary ettringite nucleation and growth must cause concrete expansion because the only known effect of the inhibitor chemicals is to reduce crystal nucleation and growth, and the inhibitors cannot in any other way be responsible for the reduction in expansion. The mechanism of operation of the inhibitors on ettringite reduction is not entirely clear but the solution growth experiments show that they prevent crystallization of a soluble ettringite precursor gel. The present study shows that ettringite growth alone is not responsible for expansion cracking because the experiments showed that most expansion occurs under wet/dry cycling, less under freeze/thaw cycling, and least under continuous soaking conditions. It was concluded from the different amounts of damage that water absorption by newly-formed, minute ettringite crystals is responsible for part of the observed expansion under wet/dry conditions, and that reduction of freeze resistance by ettringite filling of air-entrainment voids is also important in freeze/thaw environments.

Special Surface Preparation Prior to Bituminous Overlays, HR-231, 1987

Research project HR-231, "Special Surface Preparation Prior to Bituminous Overlay", was initiated in 1982 to study the effectiveness of three different crack fillers in extending pavement life. In particular, this project was designed to determine if any of the fillers could substantially reduce the rate of subsurface deterioration and general deterioration of an asphalt pavement at crack locations. This project also sought to determine the effects of the various crack filling procedures on different thicknesses of bituminous overlays. The three fillers, a fly ash slurry, an emulsion, and a rubberized asphalt mixture, were used along with a control section with no crack filler material on a 2.5 mile section of Cerro Gordo Trunk Route S-25 south of the town of Thornton. This report discusses the construction and performance of each filler material and makes recommendations concerning future use of any of the materials used.

Effects of Deicing Salt Trace Compounds on Deterioration of Portland Cement Concrete, HR-271, 1987

A study was made of the detrimental effects of trace amounts of calcium sulfate (occurring naturally in halite deposits used for deicing) on portland cement concrete pavements. It was found that sulfate introduced as gypsum with sodium chloride in deicing brines can have detrimental effects on portland cement mortar. Concentrations of sulfate as low as 0.5% of the solute rendered the brine destructive. Conditions of brine application were critical to specimen durability. The mechanisms of deterioration were found to be due to pore filling resulting from compound formation and deposition. A field evaluation of deteriorating joints suggests that the sulfate phenomena demonstrated in the laboratory also operates in the field. A preliminary evaluation was made of remedies: limits on sulfates, fly ash admixtures, treatment of existing pavement, and salt treatments. This report gives details of the research objectives, experimental design, field testing, and possible solutions. Recommendations for further study are presented.

Improved Asphalt Surfaces and Asphalt Resurfacing Performance through Crack Maintenance, HR-213, 1987

In 1980, a Vanguard High Pressure Water Blaster capable of providing 10 gallons of water per minute at 2000 psi was purchased to evaluate water blasting as a crack cleaning method prior to crack filling on asphalt concrete pavements. Afer some iniital trials demonstrated its effectiveness of removing dirt, debris and vegetation, it was included in joint and crack maintenance research on Iowa 7 in Webster County. The objective of the research was to evaluate six crack preparation methods and seven "sealant" materials. The cleaning and sealing was performed in the spring of 1983. Visual evaluations of the performance were made in the fall of 1983 and spring of 1985. Compressed air and/or high pressure water did not adequately prepare cracks less than 3/8 inch wide. Routing or sawing was necessary to provide a sealant reservoir. The water blaster was more effective than compressed air in removing dirt, debris and vegetation but this did not yield significant improvement in sealant adhesion or longevity. Periodic crack filling is necessary on ACC surfaces throughout the remaining life of the pavement.