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dc.creatorReddy, Praveena Gutha
dc.date.accessioned2012-06-07T22:46:31Z
dc.date.available2012-06-07T22:46:31Z
dc.date.created1996
dc.date.issued1996
dc.identifier.urihttps://hdl.handle.net/1969.1/ETD-TAMU-1996-THESIS-R43
dc.descriptionDue to the character of the original source materials and the nature of batch digitization, quality control issues may be present in this document. Please report any quality issues you encounter to digital@library.tamu.edu, referencing the URI of the item.en
dc.descriptionIncludes bibliographical references: p. 66.en
dc.descriptionIssued also on microfiche from Lange Micrographics.en
dc.description.abstractThe problem of reflection cracking through the conventional asphalt concrete overlays has increased the need to find new materials which could resist cracking or fracture more effectively. It is for this reason that polymers (Styrelo are added to the neat asphalt to improve the fracture resisting properties of asphalt concrete. In this study three different asphalt concrete mixtures with and without polymer (Styrelf) were used to study their fracture toughness. With four different binders and different combinations of mixtures, 18 different overlay systems were tested for their fracture toughness. Each overlay was made up of two different layers with asphalt rich sand anti-fracture (SAF) mixture as the bottom layer. Fracture mechanics concepts were used to compare the fracture properties of polymer (Styrelo modified asphalt concrete with the corresponding conventional neat asphalt concrete. Rate of crack growth is correlated with the energy line J*-integral. Crack growth rates were determined from laboratory experiments conducted on TTI overlay tester. Analysis of the experimental results showed that crack growth rate and J*-integral are correlated. In this study it was observed that the relation between the fracture material constants log(A) and (n) is not linear. A new fracture material constant (S) relating to crack speed was developed. The relationship between log(A) and (n) was found to be linear when combined with constant (S). Results showed that this new material constant (S) could lead to a better characterization of fracture toughness. Crack speed when calculated using (S) has shown better correlation with the observed experimental fatigue life. It is speculated that this new material constant (S) could be related to healing of the asphalt concrete or the plasticity effects due to unloading of the sample in overlay test.en
dc.format.mediumelectronicen
dc.format.mimetypeapplication/pdf
dc.language.isoen_US
dc.publisherTexas A&M University
dc.rightsThis thesis was part of a retrospective digitization project authorized by the Texas A&M University Libraries in 2008. Copyright remains vested with the author(s). It is the user's responsibility to secure permission from the copyright holder(s) for re-use of the work beyond the provision of Fair Use.en
dc.subjectcivil engineering.en
dc.subjectMajor civil engineering.en
dc.titleA comparison of the fracture properties of conventional and polymer-modified two-layer asphalt concrete overlay systemsen
dc.typeThesisen
thesis.degree.disciplinecivil engineeringen
thesis.degree.nameM.S.en
thesis.degree.levelMastersen
dc.type.genrethesisen
dc.type.materialtexten
dc.format.digitalOriginreformatted digitalen


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