This study aims to reduce the use of chloride-based deicers by analyzing their residual quantities on road surfaces. The freezing conditions of road surfaces were quantitatively defined using needles of consistent weight and diameter, and indoor experiments were conducted to observe changes in surface conditions caused by residual deicers under various temperatures. To validate the equipment, a deicer currently used in Korea was applied to granite plates, and the correlation between the application rates and salinity measurements obtained using the SOBO3+ device was analyzed. Subsequently, the device was employed to measure salinity changes over time by assessing the variations in residual deicer quantities on roads with different traffic volumes and application rates. To identify issues in current reapplication methods, the deicer was reapplied at 2-h intervals, and the resulting changes in salinity were monitored. Results of laboratory experiments revealed that the interval for surface state changes decreases with the temperature despite increased deicer usage, and that similar surface change patterns are presented at higher (-2 °C, -4 °C) and lower temperatures (-6 °C, -10 °C). Across all temperatures, the coefficient of determination for the surface-change graph is approximately 0.90. Equipment verification shows that 10% of sodium chloride is underestimated, whereas aqueous calcium chloride is accurately measured and no correlation is indicated between measurement accuracy and road surface temperature. Field experiments confirmed that the deicer dispersion rates increases with the traffic volume. Furthermore, the final salinity increases after the reapplication of the deicer, except in cases of high traffic volume, and that repeated applications with reduced spray amounts are more effective than single applications with higher spray amounts under low traffic conditions. Based on the findings obtained, a plan to reduce deicer usage is proposed. Future research should incorporate additional variables that affect deicer loss and surface condition changes to further refine the results.

This study evaluates adhesion strength under various conditions to ensure adhesion performance during asphalt-pavement maintenance. The adhesion performance of a tack coat varies under various conditions. Therefore, to evaluate its curing behavior, several tests, i.e., evaporation residue rate, tracking, tack-lifter, and shear bond strength tests, were conducted based on the type, amount, and curing time of the tack coat.The result of the evaporation residue rate test shows that, except for the SSC tack coat, RSC-4 and modified tack coats require similar curing times, even though the modified tack coats have a lower moisture content. Additionally, based on the evaporation residue rate, the tracking and track-lifter test results show that approximately 75% curing is required to prevent the loss of the tack coat during asphaltpavement maintenance. After maintenance work is completed, the shear bond strength was measured to evaluate the curing properties of the tack coat. The results show that the amount applied, curing degree, and shear bond strength are proportional, whereas the modified tack coat indicate a significant difference in the strength increase rate depending on the curing degree. Additionally, when dust is attached to the surface of the tack coat, the difference in strength exceeds 20%, depending on the attachment ratio.To achieve the best adhesion performance by the tack coat during maintenance work, the loss of the tack coat should be prevented by implementing the exact curing time determined experimentally, regardless of whether the tack coat is modified, and the surface where the tack coat is applied should be cleaned before application.