A study on moisture susceptibility of stone matrix warm mix asphalt

- Zycosoil can improve moisture resistance of WSMA where the siliceous aggregates used.
- Influence of SaC is more than the influence of other factors on increasing TSR.
- Influence of grading is more than the influence of other factors on decreasing TSR.
- All first and second order plus interactive terms were statistically significant.

Stone matrix asphalt (SMA) is known to have high resistance to permanent deformation and reflective cracking due to their stone structure but similar to other hot mixes it has a high energy intake during its production. Warm mix asphalt (WMA) has recently gained a lot of popularity worldwide due to environmental concerns. Moisture susceptibility as one of the drawbacks of warm mixes has been investigated by many researchers but the extent and interactive effects of different parameters affecting moisture susceptibility particularly for SMA has not yet been reported. The aim of the present study was to examine the effects of grading, bitumen content, Zycosoil content, Sasobit content and mixing temperature on moisture susceptibility of SMA warm mix asphalt (WSMA), as well as their interactions, using response surface methodology. The results indicated that the influence of Sasobit content and grading was more than the influence of other factors on tensile strength ratio -used as an index of moisture susceptibility- respectively. Also, interaction plots between factors affecting tensile strength ratio were generated that can help to understand the interactive relationship between investigated factors.