Measured And Theooretical Response Of Perpetual Pavement Structures

The Kansas Perpetual Pavement experiment includes the construction of four pavement sections on the US-75 highway designed according to the perpetual pavement concept. The sections were instrumented with strain gauges and pressures cells to measure strains and stress at the bottom of the base layer and at the top of the subbase layer. Pavement response measurements were carried out in seven occasions between July 2005 and October 2007 with a loaded truck. Measured values obtained show that longitudinal and transverse values were almost always below the average endurance limit of 70 microstrains. The measurements also showed that temperature and vehicle speed have large effects on the response of asphalt pavements. It was also observed that transverse strains were always larger than longitudinal strains. The objectives of this research are to analyze field measured pavement response data recorded at the Kansas Perpetual Pavement experiment and to compare these measured values with theoretical response values obtained from linear elastic and viscoelastic models. All this is done to validate a perpetual pavement design implemented in Kansas on the US-75 project. The linear elastic software EVERSTRESS and the finite element software ABAQUS were used to theoretically predict the pavement responses using linear elastic and viscoelastic models respectively. Results from the linear elastic analyses were similar to the measured values except for vertical pressures. On the other hand, results from the viscoelastic finite element model (FEM) were much smaller than the measured values. The FEM was run as an elastic model and the results were similar to the ones from EVERSTRESS, suggesting that there may have been a problem with the viscoelastic modeling of the asphalt concrete material.