Iowa Fisheries Research Technical Series No. 75-1 Variations in the abundance of channel catfish year classes in the upper Mississippi River and causative factors Don R. Helms, Fishery Research Biologist Fisheries Section Jerry M. Conley, Superintendent of Fisheries December, 1975

study of channel catfish in the Mississippi River to determine differences in year class abundance and causative factors

Friday Facts, October 15, 2010, Vol. 75

Bureau of Nutrition and Health Promotion part of the Iowa Department of Public Health produces of weekly newsletter about the Iowa WIC Program for the State of Iowa citizen.

Evaluation of the Argentine Nondestructive Test for Determining Concrete Compressive Strength, R-269 and MLR-75-2, 1975

The compressive strength of concrete is an important factor in the design of concrete structures and pavements. To assure the quality of the concrete placed at the project, concrete compressive cylinders are made at the jobsite. These cylinders undergo a destructive test to determine their compressive strength. However, the determination of concrete compressive strength of the concrete actually in the structure or pavement is frequently desirable. For this reason, a nondestructive test of the concrete is required. A nondestructive test of concrete compressive strength should be economical, easily performed by field personnel, and capable of producing accurate, reproducible results. The nondestructive test should be capable of detecting the extent of poor concrete in a pavement or structure due to improper handling, placement, or variations in mixing or materials.

An Investigation of Concrete Setting Time, R-265 (MLR-75-4), 1975

A water reducing and retarding type admixture in concrete is commonly used on continuous bridge deck pours in Iowa. The concrete placed in the negative moment areas must remain plastic until all the dead load deflection due to the new deck's weight occurs. If the concrete does not remain plastic until the total deflection has occurred, structural cracks will develop in these areas. Retarding type admixtures will delay the setting time of concrete and prevent structural cracks if added in the proper amounts. In Section 2412.02 of the Standard Specifications, 1972, Iowa State Highway Commission, it states, "The admixture shall be used in amounts recommended by the manufacturer for conditions which prevail on the project and as approved by the engineer." The conditions which prevail on the project depend on temperature, humidity, wind conditions, etc. Each of these factors will affect the setting rate of the plastic concrete. The purpose of this project is to provide data that will be useful to field personnel concerning the retardation of concrete setting times, and how the of sets will vary with different addition rates and curing temperatures holding all other atmospheric variables constant.

An Evaluation of Concrete Bridge Deck Surfacing in Iowa (with corrections), MLR-75-1, 1975

Iowa has been using low slump concrete for repair and surfacing of deteriorated bridge decks on a routine basis since the mid 1960'2. More than 150 bridges have been resurfaced by this method with good results. A study was initiated in 1973 to evaluate 15 bridges resurfaced with low slump concrete, and one bridge resurfaced with latex modified concrete. The evaluation includes an assessment of concrete physical properties, chloride penetration rates, concrete consolidation, and riding qualities of the finished bridge deck. Results indicate that the overall properties of these two types of concrete are quite similar and have resulted in a contractor option concerning which system shall be used on bridge deck repair/resurfacing projects.

Transportation Research Board 1920-1995 : 75 Years of Excellence...and IOWA was there from the beginning., 1995

"Certainly no one person or state was the sole impetus for something as monumental as the Highway Research Board. Yet Iowa boasts of having provided many of the key people whose vision and energies literally created and sustained the HRB during its first critical years: Anson Marston, Thomas Agg, Thomas MacDonald, and Roy Crum." -- from page 2

Soil-Cement Stabilization, Part 1, Materials and Construction, HR-75, 1962

This report covers the construction in 1961 of the soil-cement base and related pavement structure on Iowa 37 from Soldier to Dunlap, (F-861(6), Crawford, Harrison, Monona). The report also contains an account of the experimental work performed on the same road under research project HR-75.

Mahaska County, Township 75 North Range 15 West

Des Moines River Plat Maps.

Mahaska County, Township 75 North Range 16 West

Des Moines River Plat Maps.

Mahaska County, Township 75 North Range 17 West

Des Moines River Plat Maps.

Marion County, Township 75 North Range 18 West

Des Moines River Plat Maps.

Marion County, Township 75 North Range 19 West

Des Moines River Plat Maps.

Marion County, Township 75 North Range 20 West

Des Moines River Plat Maps.

75 Years on the Move!, 1988

This book was published as part of the Iowa Department of Transportation's celebration of its 75th anniversary (1913-1988). It chronicles and highlights some significant events and achievements during these 75 years. Numerous photographics accompany the text.