SimScale CAE Forum

Backcalculation of HMA Stiffness Based On Finite Element Model




MECHANISTIC Empirical Pavement Design Guide (MEPDG) was implemented in 2008 to eliminate the traditional empirical design procedure for designing the flexible pavement [1]. This method uses detailed information about traffic, climate conditions and material properties and responses. Based on the input parameters, the model predicts the possible distresses in its service life. Therefore, accurate measurement of input parameters is essential for safe and sustainable pavement which will eliminate the probable maintenance and rehabilitation cost. Stiffnesses of base, subbase and subgrade are usually independent of temperature. However, stiffness of Hot Mix Asphalt (HMA) is largely depended on temperature. HMA stiffness must be correlated with temperature for better understanding of the value. [2]

Input Data

The model to be used is shown in the figure below. The exact dimensions can be found in [2]

Geometry description from [2]

The material data for each component can also be extracted from [2].


This study determines the stiffness of HMA using numerical analysis. The numerical model is validated with the field measured values. Linear elastic analysis is performed as this type of analysis is accurate enough for regular geometry. Another reason is that while measuring the field response it was observed that upon unloading the stress-strain return to origin at the same loading rate.

Vertical stress contour plot [2]

Contour plot of horizontal strain [2]

Key Words

Asphalt pavement, falling weight deflectometer test, field instrumentation, finite element model, horizontal strain, temperature probes.

Literature & Sources

  • [1] AASHTO, AAoSHaTOec. “Mechanistic-Empirical Pavement Design Guide-A Manual of Practice.” AAoSHaT Officials, Editor (2008).
  • [2] Islam, Md Rashadul, Umme Amina Mannan, and Rafiqul A. Tarefder. “Backcalculation of HMA Stiffness Based On Finite Element Model.” World Academy of Science, Engineering and Technology, International Journal of Civil, Environmental, Structural, Construction and Architectural Engineering 7.5 (2013): 375-380.


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