Quantitative effect of droplet size and emulsion viscosity on the storage stability of asphalt emulsion

To deeply understand and quickly estimate the storage stability of asphalt emulsion, quantitative effect of droplet size and emulsion viscosity on the storage stability of asphalt emulsion is studied. An original model for relating the storage stability (S) of asphalt emulsion to the asphalt droplet size (D) and emulsion viscosity (η) is proposed, and the prediction model for the 1 d and 5 d storage stability of asphalt emulsion are established. The relation of the 1 d and 5 d storage stability of asphalt emulsion and the permissible maximum D90 of asphalt emulsion are also discussed. Results shows that the 1 d and 5 d storage stability have high correlations with the asphalt droplet diameter for the 90th cumulative volume percentile (D90) and the average emulsion viscosity at shear rate from 80 s−1 to 100 s−1. The proposed prediction equations of storage stability can quickly and accurately estimate the storage stability of asphalt emulsion. The 5 d storage stability is about 5 times of the 1 d storage stability for many emulsions. Only when the 1 d and 5 d storage stability is lower than 0.2% and 1%, respectively, the 5 d storage stability of asphalt emulsion is only slightly higher than the 1 d storage stability. Therefore, it is recommended that the 1 d and 5 d storage stability should be lower than 0.2% and 1% for asphalt emulsion with excellent storage stability. Correspondingly, the D90 should be lower than 10 μm for the asphalt emulsion at 60% of asphalt content to obtain this excellent storage stability.