Development of a Durability Test for Asphalts, May 1972

Research Project HR-124, "Development of a Laboratory Durability Test for Asphalts," was initiated in 1966 as a long-range comprehensive program. Its ultimate objective was to develop a simple, rapid laboratory test that could be used by highway engineers to select paving asphalt according to quality, to identify inferior asphalts, and to reasonably predict the useful life of asphalts once they were incorporated in the pavements.

IoWoman, April 1972

Newsletter for Commission on the Status of Women

IoWoman, December, 1972

Newsletter for Commission on the Status of Women

Effects of Cement on Moisture Migration in Concrete, Phase A, Laboratory Study of Moisture Migration in Hardened Cement Paste, HR-141, 1972

The Columbus Laboratories of Battelle Memorial Institute is currently conducting a study of the effect of cement on moisture migration in concrete as related to the problem of D-cracking of portland cement concrete pavements. The study began on December 31, 1970, and is planned as a 3-year program. The work plan, approved by the policy committee of the members of the Iowa, Kansas, and Missouri highway departments and the Federal Highway Administration, is composed of four parts. The first phase (A) of the investigation concerned the movement of moisture into and from hardened cement pastes and the dimensional changes accompanying the moisture changes. Small slab specimens of hardened neat cement pastes were prepared from 32 different cements which were prepared at the same water/cement ratio and hydrated to the same maturity factor.

Evaluation of Gap-Graded Asphalt Concrete Mixtures, Vol. 1. Physical Properties (Part I: Mechanical Properties), HR-157, Volume 1, 1972 (1973)

This report presents the results of a comparative laboratory study between well- and gap-graded aggregates used in asphalt concrete paving mixtures. A total of 424 batches of asphalt concrete mixtures and 3,960 Marshall and Hveem specimens were examined. There is strong evidence from this investigation that, with proper-combinations of aggregates and asphalts, both continuous- and gap-graded aggregates can produce mixtures of high density and of qualities meeting current design criteria. There is also reason to believe that the unqualified acceptance of some supposedly desirable, constant, mathematical relationship between adjacent particle sizes of the form such as Fuller's curve p = 100(d/D)^n is not justified. It is recommended that the aggregate grading limits be relaxed or eliminated and that the acceptance or rejection of an aggregate for use in asphalt pavement be based on individual mixture evaluation. Furthermore, because of the potential attractiveness of gap-graded asphalt concrete in cost, quality, and skid and wear resistance, selected gap-graded mixtures are recommended for further tests both in the laboratory and in the field, especially in regard to ease of compaction and skid and wear resistance.

Evaluation of Gap-Graded Asphalt Concrete Mixtures Vol. 3. Appendix, HR-157, Volume 3 (Part 3), 1972 (1973)

This report presents the results of a comparative laboratory study between well- and gap-graded aggregates used in asphalt concrete paving mixtures. A total of 424 batches of asphalt concrete mixtures and 3,960 Marshall and Hveem specimens were examined. There is strong evidence from this investigation that, with proper combinations of aggregates and asphalts, both continuous- and gap-graded aggregates can produce mixtures of high density and of qualities meeting current design criteria. There is also reason to believe that the unqualified acceptance of some supposedly desirable, constant, mathematical relationship between adjacent particle sizes of the form such as Fuller's curve p = 100 (d/D)n is not justified. It is recommended that. the aggregate grading limits be relaxed or eliminated and that the acceptance or rejection of an aggregate for use in asphalt pavement be based on individual mixture evaluation. Furthermore, because of the potential attractiveness of gap-graded asphalt concrete in cost, quality, and skid and wear resistance, selected gap-graded mixtures are recommended for further tests both in the laboratory and in the field, especially in regard to ease of compaction and skid and wear resistance.

Collective bargaining in U.S. higher education, 1960-1971 : a selective bibliography, 1972.

This document represents a substantial attempt to survey the literature of labor negotiations as it relates to the faculty in higher education.

Floods of July 12, 1972, March 19, 1979, and June 15, 1991, in the Turkey River, Northeast Iowa, HR-140, 1996

Water-surface-elevation profiles and peak discharges for the floods of July 12, 1972, March 19, 1979, and June 15, 1991, in the Turkey River Basin, northeast Iowa, are presented in this report. The profiles illustrate the 1979 and 1991 floods along the Turkey River in Fayette and Clayton Counties and along the Volga River in Clayton County; the 1991 flood along Roberts Creek in Clayton County and along Otter Creek in Fayette County; and the 1972 flood along the Turkey River in Winneshiek and Fayette Counties. Watersurface elevations for the flood of March 19, 1979, were collected by the Iowa Natural Resources Council. The June 15, 1991, flood on the Turkey River at Garber (station number 05412500) is the largest known flood-peak discharge at the streamflow-gaging station for the period 1902-95. The peak discharge for June 15, 1991, of 49,900 cubic feet per second was 1.4 times larger than the 100-year recurrence-interval discharge. The report provides information on flood stages and discharges and floodflow frequencies for streamflow-gaging stations in the Turkey River Basin using flood information collected during 1902-95. Information on temporary bench marks and reference points established in the Turkey River Basin during 1981, 1992, and 1996 also is included in the report. A flood history describes rainfall conditions for floods that occurred during 1922, 1947, 1972, 1979, and 1991.

Summary of Legislation: Iowa General Assembly, 1972

This summary of legislation enacted by the General Assembly has been prepared for the use of legislators and other interested parties. The summary of each legislative enactment has been assigned to a major subject category. This compilation provides interested persons with quick reference to legislation enacted in specific areas and generally informs persons of the contents and effective date of the legislation. NOTE: This is a large file and may take a few minutes to load.

An Estimate of the Cost to Resurface Pavements and Bridges Damaged by Studded Tires, 1972

This report contains an estimate of the cost of highway resurfacing necessitated by damage from studded tires. The total is $95,620,000 for the twenty-five years from 1971 to 1996. This total includes $51,937,000 to resurface pavements and bridges on Interstate routes and $43,683,000 for other Primary highways. The estimate for Interstate routes includes those sections now open to traffic and those planned for completion by November 1974. The estimate for other Primary routes includes rural and municipal sections open to traffic as of November 1970. The estimate was prepared by computing the cost of expected pavement and bridge resurfacing costs for the twenty-five year period assuming continued use of studded tires, then subtracting from this the expected resurfacing ) cost for the same period assuming that the use of' studded tires is prohibited. The total figure, $95,620,000, should be regarded as a conservative estimate of the cost which may be avoided by prohibiting the use of studded tires in Iowa. The conservative nature of the estimate may be demonstrated by the following examples of the guidelines used iri its preparation. 1. Only mainline pavements were included in the cost estimate for the Interstate routes. The connecting loops, exit ramps and entrance ramps at Interstate interchanges contain many additional miles of pavement subject to wear by studded tires. This pavement was omitted from the estimate because reliable ' information about the rate of pavement wear at such locations is not available. As a result, the Interstate resurfacing costs are underestimated. 2. Several other costs were also omitted from the estimate because of a lack of sufficient information. These include the cost of repairing damage caused by studded tires to city streets other than those designated as Primary routes, the damage to pavements and bridges on the more-heavily travelled Secondary roads, and the damage to pavement traffic markings on all highway systems. Experience indicates that portland cement concrete pavements in Iowa have a normal service life of twenty-five years before resurfacing becomes necessary. The service life for asphalt pavements is thirteen years. In making this cost estimate, the need for resurfacing was attributed to wear from studded tires only when the normal service life of the pavement was shortened by that wear. Consequently, this cost estimate does not account for the reduced safety and convenience to Iowa motorists during the time when pavement wear caused by studded tires is significant but less than the critical amount.