Acoustic Emission-Based Reinforcement Evaluation of Basalt and Steel Fibers on Low-Temperature Fracture Resistance of Asphalt Concrete

Abstract

This study aims to adopt the acoustic emission (AE) technique to evaluate the reinforcing effect of basalt and steel fibers on the fracture resistance of asphalt concrete (AC) under indirect tension (IDT) testing at low temperature. Control asphalt concrete (CAC) with no fibers was also tested for comparison. The AE counts and durations were recorded and analyzed to characterize the fracture processes of basalt fiber reinforced asphalt concretes (BFRAC) and steel fiber reinforced asphalt concretes (SFRAC), which were compared with the results from static displacement and strain data obtained through digital image correlation (DIC). The results revealed that the low-temperature fracture processes of BFRAC and SFRAC could be effectively divided into four stages according to the evolutions of AE parameters and corresponding cumulative AE parameters. AE properties could effectively evaluate the reinforcing effects of basalt and steel fibers on the low-temperature fracture resistance of AC, whereas static displacement and strain failed to identify the effects. BFRAC with a fiber length of 12 mm (BFRAC-12) had favorable ductile property at the final failure stage, whereas BFRAC with a fiber length of 6 mm (BFRAC-6), SFRAC with a fiber length of 6 mm (SFRAC-6), and SFRAC with a fiber length of 12 mm (SFRAC-12) exhibited brittle characteristics based on variations of AE parameters. Good correlations between the curve characteristics of AE parameters and the failure loads of AC specimens can be observed. The AE technique demonstrated great potential for the damage fracture characterization of asphalt materials.