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Settling of rubber particles in asphalt-rubber blends
|dc.description||Due 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 email@example.com, referencing the URI of the item.||en|
|dc.description||Includes bibliographical references: p. 123-126.||en|
|dc.description.abstract||Traditional asphalt-rubber binders have faced problems ics. in pavement compaction, due to phase separation or sedimentation of undissolved rubber. A homogeneous asphalt-rubber binder is desirable for alleviating this problem. In addition, a blend with a high dissolved rubber content is expected to have better performance properties. A variety of curing processes has been investigated to attain an optimal process, providing a superior asphalt-rubber blend. This research used temperature, time, shear rate, and nitrogen versus air blowing as variables to study the effect of different curing conditions. The effect of rubber content, asphalt type, and air blowing were additional studies. A1l asphalt-rubber binders in this research were prepared by a two step curing process. This process consists of two curing processes, called the first and the second curing, and two settling processes. The first curing was used to produce the blends. Then, the settling step was followed to concentrate the undissolved rubber for re-curing in the secondary curing step. Finally, the re-settling step was employed to remove a small part of the remaining undissolved rubber and to determine the homogeneity after the second cure. The settling rates and the performance grades of the blends were determined to elucidate the effect of curing conditions on the quality of the binders. The high curing temperature resulted in more rubber being disintegrated and dissolved into asphalt, due to increased reaction between asphalt and rubber. Increasing the curing time noticeably increased the size reduction and the solubility of the rubber particles. Mixing rubber with asphalt by using a high shear rate quickened the shortening of rubber chains. However, the performance grade of the binders seemed to be deteriorated by these severe curing conditions. Air blowing was conducted with an expectation of improving high temperature properties while the added rubber benefited low temperature properties. Low molecular weight asphalt or low viscosity asphalt appeared to more efficiently solubilities the ground tire rubber.||en|
|dc.publisher||Texas A&M University|
|dc.rights||This 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.subject||Major chemical engineering.||en|
|dc.title||Settling of rubber particles in asphalt-rubber blends||en|
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