Evaluating Fracture Behavior of Nano-CaCO3–Modified Asphalt Concrete Mixtures at Intermediate Temperatures

This study investigates the effects of incorporating nano-carbonate calcium (NCC) on the temperature-dependent fracture performance of hot mix asphalt mixtures. Testing was conducted at 0°C, 10°C, and 20°C using indirect tensile strength, resilient modulus, dynamic modulus, and three-point semicircular bending tests on mixtures containing two distinct neat asphalt binders and NCC particles at concentrations of 4% and 6% as binder additives. Fracture characteristics were assessed through dissipated creep strain energy, maximum cohesive strength, and cohesive fracture energy using a finite element cohesive zone model (CZM). Results indicate that the addition of NCC enhances the crack resistance and flexibility of modified asphalt mixtures, particularly evident in dissipated creep strain energy. CZM parameters, validated through three-point bending monotonic fracture tests, demonstrate increased cohesive strength values at all testing temperatures. However, cohesive fracture energy exhibits enhancement only at 20°C, declining at the other two testing temperatures across all mixtures.