Experimental Study on the Influence of Out-of-Band Gradations and Ageing on Fracture Properties of Asphalt Concrete using IDEAL-CT Test

Abstract

The need to enhance the cracking resistance of asphalt mixes under varying conditions of aging and traffic loads has become increasingly critical for sustainable pavement performance. This study explores the impact of aggregate gradation, volumetrics, and aging on the cracking potential of asphalt mixes, evaluated using the Bailey method and IDEAL-CT test. Three gradations were considered, and the mixes were subjected to unaged (UA), short-term aged (STA), and long-term aged (LTA) conditions. Gradation-2 showed the best cracking resistance, as reflected by the highest CT-Index values, though significant reduction was noted after LTA. IDEAL-CT parameters such as |m75|, fracture energy (Gf), and Asphalt Flexibility Ratio (AFR) revealed the complex interplay between stiffness, flexibility, and aging effects. The findings underline the importance of selecting optimal aggregate gradation and binder content for enhancing long-term durability and resistance to cracking in asphalt pavements.