Simple test study on anti-freeze additives selection for railway asphalt mixture (RAM) in cold region

- A clear definition to railway asphalt mixture (RAM) was made.
- Five expected abilities of anti-freeze additive selection for RAM were proposed.
- A combination of four components is recommended for anti-freeze additive.
- UEA is not suitable for being as anti-freeze additives for RAM.

The impermeability and moisture damage resistance should be enhanced if railway asphalt mixture (RAM) applied in seasonal frozen area. This paper presents an selection of anti-freeze additives for RAM by conducting highway-based laboratory tests. Five powder alternatives, hydrated lime, fly ash, red clay brick powder, Portland cement and U-type expensive agent (UEA) with different ratio and components, were prepared in terms of concepts with filling, bonding, waterproofing, reinforcing, anti-freezing and self-impermeability. Replacing 50% by weight of mineral filler was proposed in the fabrication of RAM, and the other test conditions were kept in consistence. By experiencing Marshall test, permeability test, indirect tensile test and linear shrinkage test, the results indicated that (i) the bituminous cement made from asphalt binder, mineral filler and different additives can significantly influence the performance of RAM; (ii) A potential combination with hydrated lime (40%), fly ash (20%), red clay brick powder (20%) and Portland cement (20%) can enhance the anti-freeze ability and water damage resistance of RAM; (iii) UEA commonly used in concrete with the concept of self-compaction is not appropriate for being as anti-freeze additive component for RAM.