Investigation of rheological properties of asphalt emulsions

Rheology is critical issue in the workability, stabilization and engineering performance of asphalt emulsions. The objective of this study is to investigate the rheological properties of asphalt emulsions. To achieve this goal, a preshear protocol was introduced and four kinds of asphalt emulsions were tested base on preshear. Firstly, the necessarity of preshear was analyzed and the suitable range of preshear rate and preshear time of the studied asphalt emulsions were given. Then, the rheological properties of asphalt emulsions were studied after preshear. Finally, the palierne model was modified and the storage/loss modulus of asphalt emulsions was accurately predicted by the modified palierne model. The results showed that it’s necessary to preshear asphalt emulsions before testing rheological properties. The viscosity, zero shear viscosity, storage and loss modulus of asphalt emulsions increase with the increase in solid content. The prediction results of the modified palierne model are better than that of palierne model. The storage/loss modulus of asphalt emulsions can be effectively predicted by the modified palierne model. This study has considerable meaning to the promotion of production and manufacturing of asphalt emulsions.

Prediction of Rheological Properties and Interfacial Tension of Mixtures of Immiscible Polypropylene-Polystyrene (PP3/PS) Blends

Blends of polypropylene (PP3) and polystyrene (PS) were studied and, their rheological behavior was determined and discussed in detail. The interfacial tension between the blend components was evaluated from the rheological data and the storage modulus by using two well-known models: Palierne model and Choi-Schowalter equation. The theoretical predictions were compared with experimental data obtained from PP3/PS blends. The obtained results showed that the Palierne model could predict the rheological and viscoelastic properties of the considered polymer blends. In addition, the interfacial tensions between PP3 and PS were evaluated and compared with those cited in the literature. It was also found that the Palierne model was more accurate than Choi-Schowalter one in determining the interfacial tension.