Pavement performance of semi-flexible grouted asphalt under snow-melting agents and freeze-thaw cycles

Abstract Winter road deicing improves traffic safety but the resulting brine can accelerate deterioration of semi-flexible pavements. This study investigates the coupled effects of typical chloride-based snow-melting agents (NaCl, CaCl 2 , and MgCl 2 ) on semi-flexible grouting material and asphalt-mixture pavement performance under freeze–thaw (F–T) action. Ice-melting tests were performed at −5 to −25 °C, and six grout formulations were evaluated after 50 F–T cycles (−20/+20 °C) using frost-resistance coefficient, compressive strength, and crack growth rate (replicates n≥3). Asphalt Marshall specimens were conditioned in 0.25 g ml −1 NaCl brine, pure water, and anhydrous control for 0–10 F–T cycles; surface damage was quantified by roller-strain simulation plus ImageJ analysis and Marshall stability testing (n=4). The optimal multi-salt formulation, 3% NaCl + 1% CaCl 2 + 1% MgCl 2 , was determined via multi-criteria ranking (maximize frost resistance and strength; minimize crack growth) and achieved the best overall grout performance (frost-resistance coefficient 95%, compressive strength 42.8 MPa, crack growth rate 15%), compared with the CaCl 2 -only grout (70%, 29.0 MPa, 25%). For asphalt mixtures, saline F–T exposure produced much more severe deterioration than pure-water F–T: after 10 cycles, surface porosity increased by 71.18% and Marshall stability decreased by 60.3% (pure water: 34.87% and 13.6%). These quantitative results support an evidence-based deicer composite for improved durability of semi-flexible pavements in cold regions.