Performance of segregated hot mix asphalt pavements
Abstract
A laboratory study was conducted to evaluate the performance of segregated hot mix asphalt (HMA) pavements. The study involved simulating in-situ segregation of two current projects. Tests in the study were a laboratory wheel track test (PURWheel) and triaxial tests (including resilient modulus). For each project four segregation levels were determined based on field observation and subsequent analysis of gradation, asphalt content and air voids. Specimens prepared at all four segregation levels were tested in the PURWheel device and triaxial test apparatus for both the dry/hot (60°C) and wet/hot (60°C) conditions. The PURWheel testing device has shown its potential in evaluating HMA rutting/stripping performance. The rutting and stripping potential of segregated HMA changes significantly for different segregation levels. Generally, more rutting occurs for fine and coarse segregation levels (Texas mixtures). For the same segregation level HMA rutting with hot/wet testing condition is several times higher (4 to 11) than that with hot/dry testing conditions. The triaxial test provides significant stress-strain information about HMA. Resilient modulus of HMA specimens was determined prior to the triaxial tests. Results show that the HMA resilient modulus is not sensitive to segregation level. Young's modulus of the mixtures determined from the triaxial tests is also not sensitive to segregation level. However, yield strength and maximum strength determined from the triaxial tests are sensitive to segregation level. The yield strength and maximum strength at Low and High segregation level mixtures of the Alabama project are significantly lower that those of the No and Medium segregation levels. For the Texas project, the yield strength and maximum strength of the Fine and High segregation levels are significantly lower that those at the No and Medium segregation levels. Performance of the segregated pavements were evaluated using the results from PURWheel tests, local climatic conditions, traffic projections, and scale shift factors from current studies.
Degree
Ph.D.
Advisors
Hand, Purdue University.
Subject Area
Civil engineering
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