The rheological properties and mechanisms of cement asphalt emulsion paste with different charge types of emulsion

• The rheological properties of CA paste with different asphalt emulsion type is studied.
• The influencing mechanisms of the rheological properties of CA paste is studied.
• The effect of pH value on cationic emulsion is investigated.
• The effect of emulsifier type on the rheological properties of cement paste is studied.

Cement asphalt emulsion (CA) composites are very promising materials suitable for many applications. The rheological properties of CA paste, which can reflect the workability of CA paste and the stability and demulsifying behavior of asphalt emulsion, have attracted much attention. However, the rheological properties of CA paste with different charge types of emulsion (i.e. cationic and anionic) as well as the influencing mechanisms are not clearly understood. In this paper, the rheological properties of CA paste with cationic and anionic emulsion were studied, and the potential influencing factors were analyzed, i.e. pH value, emulsifier, and the adsorption behavior between asphalt droplets and solid particles. Results indicate that the apparent viscosity of CA paste at high shear rate is mainly related to emulsifier type. However, emulsifier type and pH value are not the primary factors of the yield stress of CA paste. The yield stress of CA paste is closely related to emulsion charge types. CA paste with cationic emulsion has a higher yield stress than CA paste with anionic emulsion. This is because that the cationic asphalt droplets has a much stronger adsorbing ability on solid particles surface compared with anionic asphalt droplets.