Evaluation of bituminous surfaces produced by the turbulent-mass process

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Date Created
1976
Description
The new turbulent-mass process for mixing asphaltic concrete paving mixtures has been under study since its recent introduction in 1970. It is increasing in popularity with contractors because of two reasons: the mixing plant requires less equipment; and the process itself appears to result in a significant reduction in polluting emissions. All of this should reduce the cost of production. Field and laboratory tests and observations indicate that a satisfactory product can be produced by this process, one that is at least equal to conventional plant-mix

Deflection study of flexible pavement overlays

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Date Created
1973
Description
Beginning in 1968, Benkelman beam deflection tests were run on 25 bituminous roadways located throughout the state. Tests were run before overlay, just after these projects were overlayed, one year after, and two years after. The results were analyzed to determine the strengthening effect of the bituminous overlay. In conjunction with this study, Benkelman beam tests were run at various short intervals on a number of randomly selected flexible pavements. These results were used to develop a testing schedule (number and location of test points required) in order to assess the deflection characteristics of a flexible pavement within a given degree of accuracy.

Field trial of the calcium carbide gas pressure method of determining moisture content

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Date Created
1963
Description
On highway construction projects it is necessary to determine moisture contents of soils and aggregates in connection with earthwork, subbase, base, concrete, and bituminous construction. This determination by the present conventional methods is time consuming, and there has been increasing criticism by contractors that tests of this type are causing delays in the progress of their work. Consequently more rapid methods have been sought for making reliable moisture control tests particularly on base materials and embankment soils. The purpose of this investigation was to determine the accuracy and time saving possibilities of the Calcium Carbide Gas Pressure (CCGP) Moisture Tester when used as a field testing device in comparison with conventional field methods for moisture content determination. This report presents the results of extensive field tests with the instrument. A previous study (Investigation No. 122) had established that moisture contents can be accurately determined with this device under the ideal working conditions of the laboratory. Moisture testers were placed on 14 field projects selected so that the widest possible range of soil types could be tested. Some base and subbase materials were also tested.

Application of AASHO road test results to design of flexible pavements in Minnesota: 1964 Agreement

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Date Created
1964-12
Description
Investigation 183 began in April, 1963, with preliminary selection, of flexible pavements in each Construction District of the Minnesota Highway Department. Projects were selected where it was thought that well-defined design occurred and a good traffic history could be obtained. With the aid of the district soils engineers, the areas were checked for uniformity and forty-one test sections were laid out. In 1964 an additional nine test sections were set up, bringing the total to fifty. During the summers of 1963 and 1964 three phases of field work were completed on each test section, These were: (1) fractional plate load testing with in-place moisture and density determination of each layer and with samples of materials taken from each layer for laboratory testing, (2) determination of Benkelman beam deflections, rut depth, and cracking for each section, and (3) determination of the roughness index for each section. A second set of beam deflection tests has been run during the fall periods. Item (1) was conducted only once on each test section, i. e. on the original 41 sections in 1963 and on the nine new sections in 1964. Items (2) and (3) were conducted on all test sections in both 1963 and 1964. It is planned to run deflection and condition tests on each of the test sections on a periodic basis about once a year. The roughometer index is used along with the rut depth and cracking to determine a Present Serviceability Index as shown in Part V of this report. The trend of the PSI with traffic will define the performance of the test section.

Application of AASHO road test results to design of flexible pavements in Minnesota: 1963 Agreement

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Date Created
1963-12
Description
The purpose of Investigation 183 is to translate the findings of the AASHO Road Test to Minnesota conditions, and in general to actual highway conditions. At the Road Test, relationships between load and pavement thickness were established for one set of materials and for controlled traffic. In this investigation relationships for other embankment materials and normal highway traffic as found in Minnesota will be developed, starting with the basic relationships obtained from the Road Test

Stabilization of poor quality aggregate: TH 30 near Mapleton

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Date Created
1967
Description
In parts of Minnesota, the supply of good quality gravel is quite limited. For this reason, attempts have been made to improve the poorer quality gravel which is available thus making it, suitable for use as base material on highway projects. The purpose of this investigation was to evaluate the results of treating a typical poor quality aggregate with the following additives: portland cement, asphalt emulsion and hydrated lime. The project was constructed on a trunk highway with a relatively low traffic volume near Mapleton in Southern Minnesota in 1960. The design called for 22 test, sections, most of which were 1000 feet in length. These sections included seven with soil-cement or cement modified base, three with cement modified base using a delayed compaction procedure, two with lime treated base and seven with asphalt emulsion treated base. Two sections with untreated aggregate base and one with four inches of Class 5 base and six inches of Class 4 subbase were included as control sections. This report covers the design and construction of the project and results of tests and observations made during construction and the five-year period which followed.

Resistance R-values of typical soils and aggregates

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Date Created
1961-02
Description
The results of this investigation to date indicate that the stabilometer may be a very useful tool in the evaluation of Minnesota soils and aggregates. However, the method of applying the results of the test to the design of flexible pavements still has to be established. This remaining problem is undoubtedly the most difficult and will be the third phase of Investigation No. 176

Plate Bearing Tests on Various Trunk Highway Sections: Supplement 5

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Date Created
1960-03
Description
This investigation was begun in 1951 for the purpose of evaluating selected bituminous-surfaced highways by means of the plate bearing test. It was continued through 1952, 1953 and 1954' without significant change in procedure or purpose. In 1955 this program was interrupted by other research work and has no-t been resumed as a controlled investigation. However, nearly every year there were requests for plate bearing test data on a number of trunk highways for various purposes, and this information has been assembled in supplementary reports to Investigation No. 161. The purpose of this supplement is to report the miscellaneous plate bearing test data accumulated during 1958 and 1959.

Tests on cores drilled from 1 C.C. pavements and concrete bases placed during 1956

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Date Created
1957-03
Description
This investigation is conducted every year for the purpose of securing information as to the compressive strength and thickness of concrete pavements as constructed under present methods, and to ascertain these factors as they pertain to specification requirements. The following data are obtained for each core drilled: project number, station and location with respect to center line at which each core was drilled, date concrete was placed, date drilled, date core was tested, the height, strengths, and diameter of each core. In the summary of results some of the data is omitted and some is indicated in a different form. The date placed is omitted and the age when drilled and the age when tested is used in place of the drilling and testing dates. The height of the core as shown in the report is the height prior to capping. The location from which the core was taken is measured in the field and the data submitted with the cores for use in the report. Side cores were generally taken two feet from the outer edge of the pavement, and the center cores were taken two to six feet from the center line.