Asphalt modification and testing of performance-related cracking failure properties /
Asphalt, as a binder that glues the aggregates together, is an important part in the service life of asphalt pavement. However, its properties vary with time and temperature. Upon contact with oxygen, the compositions of an asphalt binder change causing the binder to harden and subsequently causin...
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| Format: | Thesis Book |
| Language: | English |
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[Place of publication not identified] :
[publisher not identified] ;
2003.
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| Subjects: | |
| Online Access: | http://proxy.library.tamu.edu/login?url=http://proquest.umi.com/pqdweb?did=765866931&sid=1&Fmt=2&clientId=2945&RQT=309&VName=PQD |
| Summary: | Asphalt, as a binder that glues the aggregates together, is an important part in the service life of asphalt pavement. However, its properties vary with time and temperature. Upon contact with oxygen, the compositions of an asphalt binder change causing the binder to harden and subsequently causing pavement failure. Additives, such as polymers and tire rubber, have been used to improve the performance of an asphalt binder. This work includes a study of how compositions of the base asphalt affect the performance of tire rubber-modified asphalt binders as well as a development of an aging procedure to assess the durability of an asphalt binder. A number of base asphalt binders in various compositions were manufactured in the laboratory. Tire rubber was incorporated into the bases by a high-cure process at a high temperature. The blends were performance graded based on the procedures described in the Superpave. The high-temperature properties of a blend are more influenced by the rubber content rather than by the blend compositions as rubber addition increases the viscosity of the binder. For the low-temperature performance grade, the heavy aromatics reduce the resistance to cracking by several degrees. Most pavement failures occur after several years of service. However, Superpave specification, G* sin ð , failed to screen for age hardening and fatigue cracking. DSR function, G'/([?]'/G'), which correlates well with ductility below 10 cm, offers an alternative approach to gauge fatigue failure on the road. To determine how an asphalt binder ages and when it cracks, an accelerated aging test has been developed based on the DSR function, using a failure limit of 0.003 MPa/s. As asphalt oxidation depends highly on pressure and temperature, an aging condition with the smallest relative deviation from the aging in the environmental room was considered the best test to simulate the road aging. From the kinetics standpoint, an asphalt with high initial jump tends to harden at a slower rate than asphalts with low initial jump. Also, the correlation between activation energy E and the reaction order shows that they are inversely correlated; hence there is an offsetting effect between pressure and temperature. |
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| Item Description: | Vita. "Major Subject: Chemical Engineering". |
| Physical Description: | xvii, 209 leaves : illustrations ; 28 cm. Issued also on microfiche from University Microfilm Inc. |
| Bibliography: | Includes bibliographical references (leaves 164-171). |