Investigating the effect of flexural stiffness, strain levels, and temperature on the fatigue failure of asphalt mixtures containing geocomposites in various layers

Abstract

Asphalt pavements frequently experience structural deficiency in the form of cracking, leading to expensive repair and decreased service life. Although traditional overlays are routinely employed to retard pavement degradation, the reflection of existing cracks in new overlays is a major concern. Considering this gap, the study investigates the placement of geocomposites at strategic points in asphalt slabs to assess their effectiveness in enhancing fatigue resistance, decreasing damage growth, and improving structural performance under various levels of strain and temperature. The main goal is to determine the capabilities of geocomposites in increasing pavement life through experimental fatigue testing and theoretical damage mechanics modeling, providing sustainable solutions for road repair and maintenance. The research approach entails experimental testing using the four-point bending beam apparatus in strain-controlled mode under 250, 400, 650, and 1000 microstrain strain levels. Geocomposites are placed in either the middle third or the ends of asphalt slabs, and their performance is compared with that of unreinforced specimens at ambient and sub-zero temperatures (22 and −25°C). Regression analysis is also used to establish predictive relationships between strain levels, material characteristics, and rates of deterioration. The findings indicate that geocomposite-reinforced specimens have significantly better fatigue life than unreinforced specimens, with improvements of up to 71 % for higher strain levels. The specimens reinforced at the ends perform better under higher loading, while specimens reinforced in the middle third provide better performance under lower strain levels. Reinforcement also lowers the rate of damage growth by 50 %, increasing the period between repairs of pavements. Notably, geocomposites display higher effectiveness in colder climates, where reinforced samples have over two times the fatigue life of unreinforced equivalents at a temperature of −25°C. By combining empirical findings with theoretical concepts, this research provides practical guidelines for enhancing pavement reinforcement practice, thus promoting economical and sustainable infrastructure development.