Evaluation of fracture resistance of asphalt concrete involving Calcium Lignosulfonate and Polyester fiber under freeze-thaw damage

In this study, an attempt was made to study the fracture resistance of asphalt concrete containing vertical cracks (Pure mode II) and angular cracks (Pure mode I) that were subjected to freeze-thaw damage (FTD). For this purpose, first, using ABAQUS software, the pure mode I was modeled by the previous studies' geometry; then, the samples with the obtained dimensions from the software were made in the laboratory and subjected to FTD condition. In order to improve the fracture performance of asphalt concretes under FTD conditions, two types of additives, including polyester fibers (PE) and Calcium Lignosulfonate (CL) with economic-environmental base, were used. Fracture resistance of samples was evaluated using fracture indices (obtained from the load-displacement curve), including fracture energy (G(F)), stress intensity factor (K-I and K-II), Flexibility Index (FI), Cracking Resistance Index (CRI), Toughness Index (TI), Tensile Stiffness Index (TSI), and the Tensile Strength (TS). The results showed that the proposed geometries could evaluate the fracture behavior of asphalt concrete containing angular cracks. The results also showed that 0.25PE and 6CL samples had better fracture resistance against opening crack (mode I) and in-plane sliding crack (mode II). Also, the improvement of fracture brittle performance for 0.25PE and 6CL samples justified the use of these two types of mixtures in asphalt concrete under FTD conditions.