A Laboratory Investigation into the Effects of the Aggregated Related Facts of Critical VMA in Asphalt Paving Mixtures, June 2000

This report summarizes research conducted at Iowa State University on behalf of the Iowa Department of Transportation, focusing on the volumetric state of hot-mix asphalt (HMA) mixtures as they transition from stable to unstable configurations. This has raditionally been addressed during mix design by meeting a minimum voids in the mineral aggregate (VMA) requirement, based solely upon the nominal maximum aggregate size without regard to other significant aggregate-related properties. The goal was to expand the current specification to include additional aggregate properties, e.g., fineness modulus, percent crushed fine and coarse aggregate, and their interactions. The work was accomplished in three phases: a literature review, extensive laboratory testing, and statistical analysis of test results. The literature review focused on the history and development of the current specification, laboratory methods of identifying critical mixtures, and the effects of other aggregate-related factors on critical mixtures. The laboratory testing involved three maximum aggregate sizes (19.0, 12.5, and 9.5 millimeters), three gradations (coarse, fine, and dense), and combinations of natural and manufactured coarse and fine aggregates. Specimens were compacted using the Superpave Gyratory Compactor (SGC), conventionally tested for bulk and maximum theoretical specific gravities and physically tested using the Nottingham Asphalt Tester (NAT) under a repeated load confined configuration to identify the transition state from sound to unsound. The statistical analysis involved using ANOVA and linear regression to examine the effects of identified aggregate factors on critical state transitions in asphalt paving mixtures and to develop predictive equations. The results clearly demonstrate that the volumetric conditions of an HMA mixture at the stable unstable threshold are influenced by a composite measure of the maximum aggregate size and gradation and by aggregate shape and texture. The currently defined VMA criterion, while significant, is seen to be insufficient by itself to correctly differentiate sound from unsound mixtures. Under current specifications, many otherwise sound mixtures are subject to rejection solely on the basis of failing to meet the VMA requirement. Based on the laboratory data and statistical analysis, a new paradigm to volumetric mix design is proposed that explicitly accounts for aggregate factors (gradation, shape, and texture).

Iowa Results First: Return on Investment for Corrections Programs - 2012, May 2012

The Iowa Department of Management requested the Iowa Department of Corrections to accept the Pew Center on the States’ invitation to be trained in assessing the return on investment to taxpayers from criminal justice programs utilized by the State of Iowa. Using the Results First model, a nationally recognized, peer-reviewed tool developed by the Washington State Institute for Public Policy (WSIPP), the Department of Corrections has calculated the rate of return on investment for Iowa adult offender programs for each program area included in the model.

Washington County, June 30, 2002

County Audit Report

Washington County, June 30, 2003

Independent auditor's reports, basic financial statements & supplementary information, and schedule of findings and questioned costs for the fiscal year ending June 30, 2003

Washington County, Independent Auditor's Reports, Basic Financial Statements and Supplementary Information, Schedule of Findings and Questioned Costs, June 30, 2004

County Audit Report

A Review of the Revitalize Iowa's Sound Economy Program, Administered by the Department of Transportation, July 1, 1986 through June 30, 2004

Other Audit Reports - Review

Washington County, Independent Auditor's Reports, Basic Financial Statements and Supplementary Information, Schedule of Findings, June 30, 2005

County Audit Report

Special investigation of the Washington Community School District for the period June 1, 2003 through October 31, 2006

Special investigation of the Washington Community School District for the period June 1, 2003 through October 31, 2006

Audit report on Washington County, Iowa for the year ended June 30, 2007

Audit report on Washington County, Iowa for the year ended June 30, 2007

Audit report on Washington County, Iowa for the year ended June 30, 2008

Audit report on Washington County, Iowa for the year ended June 30, 2008

Audit report on Washington County, Iowa for the year ended June 30, 2009

Audit report on Washington County, Iowa for the year ended June 30, 2009

Audit report on Washington County, Iowa for the year ended June 30, 2010

Audit report on Washington County, Iowa for the year ended June 30, 2010

Audit report on Washington County, Iowa for the year ended June 30, 2011

Audit report on Washington County, Iowa for the year ended June 30, 2011

Audit report on Washington County, Iowa for the year ended June 30, 2012

Audit report on Washington County, Iowa for the year ended June 30, 2012

Air Formed Arch Culvert Construction - Washington County, HR-313, 1994

Iowa's secondary roads contain nearly 15,000 bridges which are less than 40 ft (12.2 m) in length. Many of these bridges were built several decades ago and need to be replaced. Box culvert construction has proven to be an adequate bridge replacement technique. Recently a new bridge replacement alternative, called the Air-O-Form method, has emerged which has several potential advantages over box culvert construction. This new technique uses inflated balloons as the interior form in the construction of an arch culvert. Concrete was then shotcreted onto the balloon form. The objective of research project HR-313 was to construct an air formed arch culvert to determine the applicability of the Air-O-Form technique as a county bridge replacement alternative. The project had the following results: The Air-O-Form method can be used to construct a structurally sound arch culvert; and the method must become more economical if it is to compete with box culverts. Continued monitoring should be conducted in order to evaluate the long-term performance of the Air-O-Form method.