Guest Lecture by Dr. Thushara V.T.

Dr. Thushara from the College of Engineering Trivandrum (Kerala, India), Department of Civil Engineering was a guest at the Institute of Structural Analysis at TU Dresden. She holds a Ph.D. from Indian Institute of Technology Madras, where her research focused on the influence of aggregate gradation on the mechanical response of bituminous mixtures. With over 15 years of academic and research experience, she has guided numerous B.Tech and M.Tech projects in the area of pavement materials and design.

Her core research interests include bituminous mix design, particle packing theory, reclaimed asphalt pavement (RAP), and performance characterization using advanced testing and modelling techniques. She is currently a guest researcher at TU Dresden, Germany, under TU Dresden fellowship, contributing to the ongoing DFB funded research project SFB/ TRR 339. Her ongoing work aims to integrate particle packing- based gradation design into a multiscale framework that links morphology, rheology, and performance of Stone Mastic Asphalt mixtures—with a focus on its low- temperature performance.

Dr. Thushara has been the Principal Investigator and Co-Investigator for multiple sponsored research projects funded by State/ National agencies of India, including the Transportation Research Centre (TRC) and National Rural Infrastructure Development Agency (NRIDA), focusing on Full-Depth Reclamation, thin bituminous surfaces, and sustainable pavement technologies.

She has authored several peer-reviewed journal articles and conference papers, delivered expert talks at both national and international forums, and received the Best Paper Award at IMPACTS 2023. She also serves as a reviewer for international journals in the field of pavement engineering.

The topic of her presentation was “Optimizing the Mix: The Role of Aggregate Gradation and Packing in Asphalt Mixture Performance”

Abstract:

Aggregate gradation plays a pivotal role in defining the internal structure, mechanical behavior, and long-term performance of asphalt mixtures. While traditional mix design methods have emphasized achieving target volumetric properties, often through dense gradations and binder adjustments, emerging research highlights the need for a more fundamental approach grounded in particle packing theory.

This lecture explores how gradation, viewed through the lens of granular interaction and packing density, can be strategically engineered to influence critical performance outcomes such as rutting resistance, fatigue life, and structural stability. By integrating classical and advanced particle packing models, such as the Lees approach and the Compressible Packing Model (CPM), researchers and engineers can shift from empirical to rational design paradigms.

The talk delves into the influence of coarse aggregate interlock, filler distribution, and mastic volume on the mechanical response of asphalt mixtures. It also touches upon the use of image-based analysis to quantify internal structure and segregation, and the application of viscoelastic models and relaxation spectra to assess the sensitivity of test protocols to gradation changes.

The presentation further briefly outlines the presenter’s ongoing research at TU Dresden, aligned with the SFB initiative, and illustrates how these insights are being integrated into the development of a multiscale framework that links morphology, rheology, and performance in Stone Mastic Asphalt mixtures, with a particular focus on enhancing low-temperature performance.

We thank Dr. Thushara and all the participants!