ABSTRACT
As a composite suspension, the workability of fresh cement asphalt emulsion (CA) paste is dependent on asphalt to cement mass ratio (A/C), water-cement ratio (W/C), and emulsion types. The characteristics of W/C for construction of fresh CA paste with different A/C was investigated through studying viscosity of CA paste and flow time of CA mortar. A viscosity prediction model was employed to get the relation of particle volume fraction and viscosity, and the relation of W/C and viscosity about CA pastes with different A/C was established. The W/C range corresponding to viscosity from 0.15 Pa.s to 0.3 Pa.s was discussed. Results show that the required W/C should be adjusted according to A/C and emulsion types. Also, the W/C sensitivity on the viscosity of CA pastes is related with A/C and emulsion types. The required W/C of CA pastes increases stably with the increasing A/C except the one with anionic asphalt emulsion at an A/C of 0.12. CA pastes with cationic asphalt emulsion require higher W/C than those with anionic asphalt emulsion to gain the same viscosity at the same A/C. Meanwhile, the W/C sensitivity on the viscosity of CA pastes with cationic asphalt emulsion is less than those with anionic asphalt emulsion. The effect of W/C on the flow time of two typical CA mortar was studied. The required W/C is low for high-strength CA mortar with anionic asphalt emulsion, and its change is very sensitive to flow time. Inversely, the required W/C is high and not sensitive to flow time for low-strength CA mortar with cationic asphalt emulsion. Results can give good advices about the workability of CA mortar for the real construction.
