Investigation on snow-melting performance of asphalt mixtures incorporating with salt-storage aggregates

- Salt-storage aggregates (SSA) were prepared.
- Asphalt mixtures with different SSA contents were prepared.
- Engineering properties of asphalt mixtures were tested.
- Salt-release performance of asphalt mixtures with SSA was investigated.
- Field snow-melting test was conducted by outdoor experiments.

Chloride salts are the most commonly used chemicals that serve as snow-melting agents for winter highway maintenance due to their abundance and low cost. However, the heavy use of chloride-based deicers has caused a series of environmental problems, because the deicers are directly spread on the pavement surface before snowing. Therefore, how to decrease the damage of chloride salts on pavement and environment is very important. Thus, introduction of the deicer into the asphalt mixtures and making the deicer slow release has brought a recent scientific and industrial interest. In this work, salt-storage aggregates (SSA) were innovatively prepared. Asphalt mixtures incorporating 0%, 5%, 10%, 15% and 20% SSA by volume as limestone aggregates (LSA) were prepared and their engineering properties were tested, such as high temperature stability, crack resistance at low temperature and water stability. In addition, salt-release performance of asphalt mixtures with SSA was investigated. Finally, field snow-melting test was conducted by outdoor experiments of the asphalt mixtures. The results show The SSA possesses excellent water stability, high mechanical strength and salt-storage function. The properties of asphalt mixtures with SSA can meet the requirements of specification, but the influence of SSA on water stability of asphalt mixtures should be noticed. The electrical conductivity of asphalt mixtures increases with the increase of SSA content. Salt precipitation amount per unit area increases and then gradually becomes stable with the increase of soaking time. Salt precipitation amounts from asphalt mixtures increase with the standing time and the SSA content. The asphalt pavement with SSA can possess satisfied snow-melting performance in reference to the simulated field tests.