Field Evaluation of Class A Subbase Using Fly Ash, MLR-87-3, 1988

This project consisted of slipforming a 4-inch thick econocrete subbase on a 6-mile section of US 63. The project location extends south from one mile south of Denver, Iowa to Black Hawk County Road C-66 and consisted of the reconstruction and new construction of a divided four-lane facility. The econocrete was placed 27.3 feet wide in a single pass. Fly ash was used in this field study to replace 30, 45 and 60 percent of the portland cement in three portland cement econocrete base paving mixes. The three mixes contained 300, 350 and 400 pounds of cementitious material per cubic yard. Two Class "C" ashes from Iowa approved sources were used. The ash was substituted on the basis of one pound of ash for each pound of cement removed. The work was done October 6-29, 1987 and May 25-June 9, 1988. The twelve subbase mixes were placed in sections 2500 to 3000 feet in length on both the north and southbound roadways. Compressive strengths of all mixes were determined at 3 and 28 days of age. Flexural strengths of all mixes were determined at 7 and 14 days. In all cases strengths were adequate. The freeze/thaw durability of the econocrete mixes used was reduced by increased fly ash levels but remained above acceptable limits. The test results demonstrate the feasibility of producing econocrete with satisfactory properties even using fly ash at substitution rates up to 45 percent.

Black Hawk County, June 30, 2002

County Audit Report

Black Hawk County Criminal Justice Information System, June 30, 2002

Other Audit Reports

Black Hawk County Criminal Justice Information System, June 30, 2003

Other Audit Report - 28E Organization

Black Hawk County, June 30, 2003

County Audit Report

Black Hawk 2004 Annual County Profile, 2004

County Profile

Black Hawk County Criminal Justice Information Systems, Independent Auditor's Reports, Financial Statement and Required Supplementary Information, Schedule of Findings, June 30, 2004

Other Audit Reports - 28E Organizations

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

County Audit Report

Black Hawk County Criminal Justice Information System, Independent Auditor's Reports, Financial Statement and Required Supplementary Information, Schedule of Findings, June 30, 2005

Other Audit Reports - 28E Organization

Soil Survey of Black Hawk County, Iowa, 2005

The general soil map, which is a color map, shows the survey area divided into groups of associated soils called general soil map units. This map is useful in planning the use and management of large areas. To find information about your area of interest, locate that area on the map, identify the name of the map unit in the area on the color-coded map legend, then refer to the section General Soil Map Units for a general description of the soils in your area.

Iowa African-American Journal, February 2006, Black History Month Special Edition

Newsletter for the Iowa Commission on the Status of African-Americans. Black History Month Special Edition.

Iowa African-American Journal, February 2005, Black History Month Special Edition

Newsletter for the Iowa Commission on the Status of African-Americans. Black History Month Special Edition.

Audit report on the Black Hawk County Criminal Justice Information System for the year ended June 30, 2006

Audit report on the Black Hawk County Criminal Justice Information System for the year ended June 30, 2006

Audit report on the Black Hawk County Criminal Justice Information System (CJIS) for the year ended June 30, 2007

Audit report on the Black Hawk County Criminal Justice Information System (CJIS) for the year ended June 30, 2007

Audit report on the Black Hawk County Criminal Justice Information System for the year ended June 30, 2008

Audit report on the Black Hawk County Criminal Justice Information System for the year ended June 30, 2008