Development of an Open-Source R/Shiny Tool for Resilient Modulus Coefficient Interpretation in Pavement Engineering

The resilient modulus is one of the primary parameters used in mechanistic–empirical pavement design methods and plays a fundamental role in pavement structural analysis and performance prediction. In Brazil, the implementation of the MeDiNa pavement design framework has increased the demand for accessible tools capable of supporting nonlinear modeling and coefficient interpretation. However, many available approaches still rely on proprietary software or spreadsheet-based workflows, limiting reproducibility, accessibility, and usability in teaching and research applications. This study presents the development of an open-source application based on R and Shiny for resilient modulus coefficient interpretation using the composite model adopted in the Brazilian MeDiNa methodology. The proposed application allows spreadsheet-based data importation, automated nonlinear coefficient estimation through nonlinear least-squares regression, graphical visualization of resilient modulus behavior, and generation of interactive three-dimensional response surfaces. Experimental datasets obtained from soil–aggregate mixtures, and published resilient modulus databases were used for validation. The results showed that the application successfully estimated the model coefficients and reproduced the stress-dependent resilient modulus behavior of the analyzed materials. The proposed tool provides an accessible and reproducible computational workflow for resilient modulus interpretation in pavement engineering research, teaching activities, and preliminary laboratory analyses associated with the MeDiNa framework.