The Problem:
The loaded wheel tester (LWT) testing involves using one or multiple loaded wheels to apply a moving load to an asphalt mixture specimen to measure its performance. LWT is widely used across the globe to evaluate the resistance of asphalt mixtures to rutting and moisture susceptibility. However, very little success has been made regarding use of LWT to characterize the fatigue cracking of asphalt mixtures due to the confounding effects of rutting, creep, and elastic deformation under moving load.
The Solution:
Researchers at the University of Tennessee have developed a process capable of eliminating the creep effect in fatigue cracking testing. A linear variable differential transformer (LVDT) is used to measure the deformation information under the moving load. The total deformation is then decomposed into three deformation components and thus the creep deformation can be removed. With the creep effect excluded, the fatigue characteristics of asphalt mixtures and the fatigue service life of asphalt pavements can be accurately determined.
Benefits:
• Removes creep response from total deformation
• The first and only testing and analysis system for LWT that accurately evaluates fatigue characteristics and fatigue life of asphalt pavements
• Defines multiple failure criteria for fatigue cracking, including resilient strain response, resilient modulus, and dissipated energy concept.
The Inventor:
Dr. Baoshan Huang is the Edwin G. Burdette Professor in the Department of Civil and Environmental Engineering at the University of Tennessee. He received his Ph. D in civil engineering from Louisiana State University and his M.S. and B.S. degrees from Tongji University in Shanghai, China. Huang joined UT after working with the Louisiana Department of Transportation and Development as a senior research engineer. Huang’s professional career has been devoted to geotechnical and pavement engineering.