Project Title: Utilization of Recycled Concrete Aggregates for Developing High-Performance and Durable Flexible Pavement 

Project Coordinator: Dr. Merve Akbaş Kaplan (Istanbul Technical University)

Award: Turkish National Committee of Roads (YTMK) –Article Award

Award Ceremony Date: May 2025

Investigators: Dr. Bilal Özaslan (Kırşehir Ahi Evran University / Tokyo Institute of Technology), Prof. Dr. Recep İyisan (Istanbul Technical University)

Project Topic: This study investigates the applicability of recycled concrete aggregates (RCA), obtained from large-scale urban transformation projects in Istanbul, for developing high-performance and durable flexible pavement layers. A comprehensive experimental program was conducted to evaluate the stiffness characteristics, permanent deformation behavior, and durability performance of RCA-based base and subbase materials under various freeze–thaw cycles. In addition, three modulus prediction models—the Mechanistic-Empirical Pavement Design (MEPD) model, the Power model, and the Uzan model—were compared to analyze the engineering parameters governing the behavior of RCA under different environmental conditions and to assess their implications for pavement design. Complementary numerical analyses were performed to examine the deformation response of RCA layers under multiple wheel loads and heavy traffic conditions, providing critical insights into the long-term performance of RCA-based pavement structures. The findings of the study contribute to the scientific foundation for integrating RCA into pavement design practices in Türkiye within the framework of sustainable materials management, reduced environmental impact, and circular economy principles.The article resulting from this study was published in Issue 407 of the Construction and Building Materials journal. This research enhances scientific understanding of sustainable pavement design and provides a basis for the integration of RCA into national road engineering practices. The project also highlights the long-term performance of RCA in flexible pavements, supporting environmentally responsible and resource-efficient infrastructure development.