Acoustic Emission–Based Statistical Modeling of Low-Temperature Damage in Steel Slag and Crumb Rubber–Modified Asphalt Mixture

ABSTRACT The utilization of steel slag as aggregate in asphalt pavement construction offers environmental benefits by reducing land resource occupation and substituting natural aggregates, contributing to sustainable development. However, in seasonally frozen regions, asphalt pavements are prone to low-temperature cracking due to freeze-thaw (F-T) cycles, significantly shortening their service life. This study employed acoustic emission (AE) to monitor the semicircular bending failure process in real time for steel-slag and crumb rubber–modified asphalt mixtures (SAMs) conditioned in aqueous and saline (8 % sodium chloride) environments. By coupling AE parameters (ring count, energy, b-value) with mechanical responses, we quantitatively characterized the multiscale damage evolution from crack initiation to interfacial failure. A Weibull-based statistical damage model was developed to describe deterioration under combined environmental and mechanical effects. Results show that as F-T cycles increase (0, 5, 10, 20), the fracture energy of SAM decreases by 20 to 50 %, with saline conditioning causing 14 % greater degradation than water conditioning. Rapid increases in AE ring count indicate interfacial debonding, whereas declines in b-value mark the transition from microcrack accumulation to macrocrack dominance. The proposed model effectively captures nonlinear damage evolution under F-T and mechanical loading, providing a framework for designing crack-resistant, durable steel slag asphalt pavements in cold regions.