Soil Stabilization with Lime Fly Ash, Iowa Highway Research Board Bulletin No. 26, 1961

The sixth in a series, this bulletin further compiles the reports on completed research done for the Iowa State Highway Research Board under its Project HR-1, The loess and glacial till materials of Iowa; an investigation of their physical and chemical properties and techniques for processing them to increase their all-weather stability for road construction. The research, started in 1950, has been conducted by the Iowa Engineering Experiment Station at Iowa State University under its Project 283-S.

Methods for Testing Engineering Soils, Iowa Highway Research Board Bulletin no. 21, 1960

This bulletin is a further compilation of the reports on completed research done for the Iowa State Highway Research Board Project HR-1 The loess and glacial till materials of Iowa; an investigation of their physical and chemical properties and techniques for processing them to increase their all-weather stability for road construction. The research, started in 1950, was done by the Iowa Engineering Experiment Station at Iowa State University under its project 283-S. The project was supported by funds from the Iowa State Highway Commission.

Soil Stabilization with Cement, Iowa Highway Research Board Bulletin No. 23, 1961

This is the fourth publication in a series of compilations of the reports on research completed for the Iowa State Highway Commission. This research was done for the Iowa State Highway Research Board Project HR-1. The Loess and Glacial Till Materials of Iowa; an Investigation of Their Physical and Chemical Properties and Techniques for Processing Them to Increase Their All-Weather Stability for Road Construction. The research, started in 1950, was done by the Iowa Engineering Experiment Station under its project 283-S. The project was supported by funds from the Iowa State Highway Commission.

Soil Stabilization with Lime, Iowa Highway Research Board Bulletin No. 25, 1961

This is the fifth publication in a series of compilations of the reports on research completed for the Iowa State Highway Commission. This research was done for the Iowa State Highway Research Board Project HR-1, "The Loess and Glacial Till Materials of Iowa; an Investigation of Their Physical and Chemical Properties and Techniques for Processing Them to Increase Their All-Weather Stability for Road Construction." The research, started in 1950, was done by the Iowa Engineering Experiment Station under its project 283-S. The project was supported by funds from the Iowa State Highway Commission. The principal objectives of the project may be summed up as follows: 1. To determine by means of both field and laboratory studies the areal and stratigraphic variation in the physical and chemical properties of the loess and glacial till materials of Iowa. 2. To develop new equipment and methods for evaluating physical and chemical properties of soil where needed. 3. To correlate fundamental soil properties with the performance of soils in the highway structure. 4. To develop a scientific approach to the problem of soil stabilization based on the relationships between the properties of the soils and those of the admixtures. 5. To determine the manner in which the loess and glacial till materials of Iowa can be processed for optimum performance as highway embankments, sub-grades, base courses, and surface courses.

Iowa Highway Research Report No. 2, 1950-1951

During the fiscal year, July 1, 1950 to June 30, 1951, the Iowa State Highway Commission expanded its research program by adding to the work under way during the previous fiscal year, fifteen substantial projects recommended to the Commission by the Iowa Highway Research Board. The major portion of the projects under way in the previous fiscal year have been active in this fiscal year. All of the additional projects have gotten under way during this fiscal year. This year, as in the past, the work has been performed partly by Commission forces and partly by outside agencies such as the Institute of Hydraulic Research at Iowa City, the State University of Iowa, Iowa State College, the Iowa Geological Survey and the United States Geological Survey. The major portion of the fifteen new projects has been assigned to these outside agencies.

Factors influencing stability of granular base course mixes, 1969

The objectives of this final report; Iowa Highway Research Board Project HR-99 by J.M. Hoover, was to evaluate the various factors influencing the stability of granular base course mixes.

Development of a Laboratory Durability Test for Asphalts, HR-124, 1967

Fruitful research on durability of paving asphalts may come from two approaches: The improvement of the asphalt for durability; The development of relatively rapid laboratory tests which will enable the design engineer to select or to specify an asphalt based on quality and to make a correct estimate of the service life of a selected asphalt when used in a specific paving mixture. Research Project HR-124, "Development of a Laboratory Durability Test for Asphalts," sponsored by the Iowa Highway Research Board is in the second category and was intended to be the initial stage of an overall study in the development of a durability test for paving asphalts.

Iowa DOT Project Management Peer Exchange, 2016

This project supported the planning and conduct of a two-day Iowa Department of Transportation–hosted peer exchange for state agencies that have implemented some or all of the suggested strategies outlined in the Second Strategic Highway Research Program–sponsored project R10, Project Management Strategies for Complex Projects. Presentations were made by participating states, and several opportunities were provided for directed discussion. General themes emerging from the presentations and discussions were identified as follows: To implement improvements in project management processes, agency leadership needs to decide that a new approach to project management is worth pursuing and then dedicate resources to developing a project management plan. The change to formalized project management and five-dimensional project management (5DPM) requires a culture shift in agencies from segmented “silo” processes to collaborative, cooperative processes that make communication and collaboration high priorities. Agencies need trained project managers who are empowered to execute the project management plan, as well as properly trained functional staff. Project management can be centralized or decentralized with equal effect. After an agency’s project management plan and structure are developed, software tools and other resources should be implemented to support the plan and structure. All projects will benefit from enhanced project management, but the project management plan should specify appropriate approaches for several project levels as defined by factors in addition to dollar value. Project management should be included in an agency’s project development manual.

Validation of Gyratory Mix Design in Iowa, TR-667, 2016

The design number of gyrations (Ndesign) introduced by the Strategic Highway Research Program (SHRP) and used in the Superior Performing Asphalt Pavement (Superpave) mix design method has been commonly used in flexible pavement design throughout the US since 1996. Ndesign, also known as the compaction effort, is used to simulate field compaction during construction and has been reported to produce air voids that are unable to reach ultimate pavement density within the initial 2 to 3 years post-construction, potentially having an adverse impact on long-term performance. Other state transportation agencies have conducted studies validating the Ndesign for their specific regions, which resulted in modifications of the gyration effort for the various traffic levels. Validating this relationship for Iowa asphalt mix designs will lead to better correlations between mix design target voids, field voids, and performance. A comprehensive analysis of current Ndesign levels investigated the current levels with existing mixes and pavements and developed initial asphalt mix design recommendations that identify an optimum Ndesign through the use of performance data tests.

Early History of the Iowa State Highway Commission

A narrative of the early years of the Iowa State Highway Commission from its founding in 1904 to 1921.

X-Ray Diffraction of Highway Materials, HR-128, 1969

X-ray diffraction data during adsorption of water vapor on Na- and Ca-montmorillonites show that interlayer expansion is continuous but nonuniform. X-ray and adsorption isotherm data indicate an ice-like configuration of water molecules is completed with the fourth layer of interlayer water for the Ca-clay; a fifth layer intrudes to give a less ordered structure. Data for the Na-clay indicate a laminar stacking arrangement for up to three layers of interlayer water. The Na-clay adsorbs more than twice as much water and undergoes four times as large a volume change than the Ca-clay. The free energy change during adsorption of water vapor on the Ca-clay is nearly twice that for the Na-clay. Free energy changes with increasing relative pressure reflect interlayer expansion increments.

Comparison Between Leaded and Nonleaded Gasoline as Used in Iowa State Highway Commission Vehicles, HR-1002, 1972

The overall objective of this experimental program was to obtain quantitative comparisons between leaded and nonleaded gasolines as used in a variety of Iowa State Highway Connnission vehicles. These quantitative comparisons were to be made in terms of exhaust emissions, maintenance costs and fuel economy.

Iowa Highway Programs, Finances, and Progress, 1951

(a) Iowa has a total of 101,620 miles of rural roads, both primary and secondary. (b) On January 1, 1951, a total of 68,869 miles of these rural roads were surfaced - mostly with gravel and crushed stone. (c) Additional roads are being surfaced at the rate of 2676 miles per year. (d) Iowa's highway program provides for a surfaced road to every reasonably located rural home and a paved or other type of dustless surface on all primary roads. (e) Iowa's highway funds come 26.0 per cent from property taxes, 63.5 per cent from road use taxes, 10.5 per cent from Federal aid. (f) Annual income under present laws, available for highway construction, is approximately For primary roads ----------------- $24,000,000 For secondary roads---------------- $41,967,000 (g) Iowa's highway improvements are being paid for as built. No new bonds are being issued. (h) Unobligated available farm to market road funds are rapidly being placed under contract. (i) The letting of highway contracts is increasing rapidly. (j)- Iowa's highway program is estimated to cost $945,000,000 and will require twenty years to build. These are the highlights of Iowa's highway program. The details will follow in succeeding paragraphs.

Iowa Highway Programs, Finances, and Progress, 1952

(a) Iowa has a total of 101,620 miles of rural roads, both primary and secondary. (b) On January 1, 1952, a total of 71,493 miles of these rural roads were surfaced - mostly with gravel and crushed stone. (c) Additional roads are being surfaced at the rate of 2662 miles per year. (d) Iowa's highway program provides for a surfaced road to every reasonably located rural home and a paved or other type of dustless surface on all primary roads. (e) Iowa's highway funds come 26.0 per cent from property taxes, 63.5 per cent from road use taxes, 10.5 per cent from Federal aid. (f) Annual income under present laws, available for highway construction, is approximately For primary roads------------------$23,000,000 For secondary roads---------------- 41,967,000 (g) Iowa's highway improvements are being paid for as built. No new bonds are being issued. (h) The surplus of farm to market road funds created during and immediately following the War have now been placed under contract, with only a minimum working balance remaining in the fund. (i) Iowa's highway program was estimated to cost $945,000,000 and to require twenty years to build, by the 1948 Legislative Committee. This estimate would now have to be increased due to price increases and higher required standards. These are the highlights of Iowa's highway program. The details will follow in succeeding paragraphs.

Iowa Highway Program, Finances and Progress, 1954

(a) Iowa has a total of 101,451 miles of rural roads, both primary and secondary. (b) On January 1, l954, a total of 77,024 miles of these rural roads were surfaced - mostly with gravel and crushed stone. This is 5,53l miles greater than on January l, 1952. (c) Additional roads are being surfaced at the rate of 2766 miles per year. (d) Iowa's highway program provides for a surfaced road to every reasonably located rural home and a paved or other type of dustless surface on all primary roads. (e) Iowa's highway funds come 25.4 per cent from property taxes and special taxes......................................$29,708,546.67 63.7 per cent from road use taxes.......... 74,581,080.30 10.6 per cent from Federal Aid (1952 Act).. 12,424,000.00 0.3 per cent from miscellaneous receipts.. 287,922.86 ---- ------------- 100.0 $117,001,549.83 (f) Annual income under present laws, available for highway construction, is approximately, For primary roads $29,420,000.00 For secondary roads $44,328,000.00 In 19_3, $7,299,000 of secondary road construction funds was transferred to the maintenance fund. (g) Iowa's highway improvements are being paid for as built. No new bonds are being issued.