Cement asphalt mortar (CA mortar) is a highly flowable grouting material used in the slab track structure. Temperature significantly influences the workable time of CA mortar. The workable time of CA mortar is controlled by the adsorption of asphalt droplets in the emulsion on cement grains. In the present study, the absorption behaviours under different temperatures were investigated to reveal the influences of temperature on workable properties of CA mortar. A laser particle size analyzer was employed to characterize the particle size variation in the cement and asphalt emulsion (CAE) system. The results indicated that the particle size increased more prominently at elevated temperature; The viscosity of the CAE system was measured by a rotational viscometer, results indicated that variation pattern of viscosity correlated well with that of the particle size in the CAE system and the increase of particle size was partially accountable for the increase of viscosity and impairing the flowability of CA mortar; the workable properties of CA mortar were also investigated, results showed that the slump flow increased and the workable time decreased with the increase of temperature. The addition of non-ionic emulsifier could retard the adsorption behaviour between cement and asphalt and prolong the workable time of CA mortar.