n Journal of the South African Institution of Civil Engineering = Joernaal van die Suid-Afrikaanse Instituut van Siviele Ingenieurswese - Indirect tensile fatigue performance of asphalt after MMLS3 trafficking under different environmental conditions : technical paper
|Article Title||Indirect tensile fatigue performance of asphalt after MMLS3 trafficking under different environmental conditions : technical paper|
|© Publisher:||South African Institution Of Civil Engineering (SAICE)|
|Journal||Journal of the South African Institution of Civil Engineering = Joernaal van die Suid-Afrikaanse Instituut van Siviele Ingenieurswese|
|Author||Lubinda F. Walubita, Fred Hugo and Amy L. Epps Martin|
|Publication Date||Jan 2002|
|Pages||2 - 11|
|Keyword(s)||Accelerated pavement testing (APT), Environmental conditions, Fatigue performance and MMLS3|
Cores were extracted from test sections of an in-service asphalt pavement that were trafficked with the Model Mobile Load Simulator (MMLS3) under different environmental conditions (dry, hot and wet) to assess pavement performance/damage through indirect tensile fatigue testing. Particular emphasis was placed on the effect of water during wet trafficking. Analysis was based on a comparison of the residual fatigue life of trafficked core-specimens compared to untrafficked core-specimens, and the difference (represented as a ratio) was construed as indicative of the performance/damage of the asphalt under the corresponding environmental conditions (dry, hot and wet) during MMLS3 trafficking. Under dry and hot MMLS3 trafficking conditions, the asphalt exhibited improved fatigue performance due to material densification. The asphalt from the wet trafficked sections manifested a decrease in fatigue life relative to the untrafficked asphalt due to water damage. Moisture damage in the asphalt was evident through degradation, loss in strength and stiffness, micro cracking and stripping. From the findings, it was apparent that for asphalt materials susceptible to moisture damage, the fatigue life expectancy is significantly reduced by wet trafficking such that even light axle loads (2, 1 kN) with high tyre pressures (690 kPa) cause substantial damage. Overall, the study demonstrated that the MMLS3 used in conjunction with laboratory fatigue testing is a valuable APT tool that can be used to evaluate the response and performance of the surface layers of full-scale, in-service asphalt pavements under different environmental conditions.
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