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https://nap.nationalacademies.org/catalog/27432/critical-issues-in-transportation-for-2024-and-beyond

Bituminous base course stabilization development project. Laboratory study

Bitumia sisaltavien kerrosstabilointien kehittamistutkimus. Laboratoriokokeet

The study established the basis for stabilizations service life evaluation method based on laboratory tests and in-situ trials. It contained development of reference materials for service life evaluation, test methods for stabilization mixtures and research on functional properties and their sensitivities with different compositions and densities. For specimen preparation a method was used where the specimens were compacted to a certain target density using gyratory compactor experiments (instead of Proctor experiments). A gyratory compactor method was better suited especially for choosing a target density of a warm stabilization mixture with recycled asphalt. It was determined in the study that it is necessary to keep in service a possibility to proportion stabilization mixture either using an empirical or experimental method. The empirical equations for binder content calculations in the Stabilization specifications gave too high values from the deformation resistance point-of-view in proportion of a remixer stabilization mixture. A risk of deformation increased if the density of the specimen was low. A good deformation resistance of a remixer stabilization was achieved if the bitumen content was 1 % lower than the content calculated by empirical equations of the Stabilization specifications. The preliminary trials of foam bitumen stabilization may be accelerated if necessary by storing the specimens at a temperature of +40 degrees centigrade. It was necessary to use an anti-stripping agent in a foam stabilization mixture, if it has not been shown that it is unnecessary. The need of an anti-stripping agent can be shown with a water resistance test. A cement/bitumen ratio of 0,33 is a good basis for the mix design of a composite stabilization. Cement will bind extra water of the mix and accelerates the increase of the initial strength. The composite stabilization specimens must be stored in humid air until the start of the tests. The essential points affecting the properties of a stabilization are binder content, gradation and density of the mixture. The results describe a data base of effects of these parameters consisting of many studies. Special attention must be paid to compaction of stabilization mixture both in laboratory specimen preparation and on site circumstances. The studied functional properties of foam-, remixer- and composite stabilization were resistance to water, frost, salt and deformation both stiffness modulus. Results of the study contain remarkable new information about the properties of the stabilizations and points affecting their quality and performance. This information was brought into use already during the research project through the construction specifications and construction practice. This report may be found at http://alk.tiehallinto.fi/julkaisut/pdf2/3201070-vbiumia_sisalt_kerrosstab_keh.pdf

Language

  • Finnish

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Filing Info

  • Accession Number: 01104608
  • Record Type: Publication
  • Source Agency: TRL
  • ISBN: 978-951-803-963-4
  • Files: ITRD
  • Created Date: Jul 17 2008 12:49PM