Migration characteristic and model of chloride ions for NaCl-based salt storage asphalt mixtures

摘要

The objective of the present study was to investigate the migration characteristics and model of chloride ions in salt storage asphalt mixtures under various working condition through natural leaching test. Three doses of NaCl-based salt storage fillers, two leaching temperatures, and seven freely leaching times were designed to simulate different work environment in this study. Auto ions analyser was utilized to characterize residual chloride ions content in salt storage asphalt mixtures before and after water leaching process, which indirectly stated the movement behaviour of sodium chloride from sample into water. And Fick's second law was used to establish migration model of residual chloride ions content in salt storage asphalt mixtures. The results show that residual chloride ions content and attenuation rate of salt storage asphalt mixtures all decreased with increasing leaching time. Also, high leaching temperature and content of salt storage fillers resulted in accelerating the motion of chloride ions in early leaching stage. The deviation analysis indicated that the established migration model of chloride ions had good accuracy except low usage of salt storage fillers or short water leaching time. The migration model could predict the residual chloride ions content in the salt storage asphalt mixtures under certain work condition. (C) 2021 Elsevier Ltd. All rights reserved.