![]() ![]() Emulsions are classified as Rapid Setting-1(RS-1), Rapid Setting-2(RS-2), Medium Setting (MS), Slow Setting-1 (SS-1), Slow Setting-2 (SS-2). An Emulsion is said to break when the organic and the aqueous phase separate into two distinct layers i.e. Once it breaks the bitumen breaks out and the color changes to black. The Cationic Bitumen Emulsion is chocolate brown and free-flowing at normal temperature. A depiction of the application is shown below: Thus the cationic emulsion has two breaking mechanisms at work and will break faster than a corresponding anionic emulsion. The emulsion also loses water by evaporation. The bitumen drops are immediately attracted to the surface and begin to break. In an application of cationic emulsion, we are applying positively charged drops of bitumen to a negatively charged surface. Selection of emulsifier & its quality is significant for emulsion stability, its breaking & curing when applied over aggregates. These bitumen droplets have an affinity with the negatively charged aggregate.ĭispersion is obtained by processing bitumen & water-based solution under controlled conditions through a colloidal mill having a high-speed rotor in the presence of scientifically selected surfactants/emulsifiers. The bitumen globules are positively charged due to the NH3 + group cover which is formed around bitumen droplets and provides stability for emulsion by electrostatic repulsion. A typical cationic emulsifying agent is shown below along with a diagram showing the orientation of the agent at the bitumen-water interface and the positive charge imparted to each drop.Ī stable dispersion of bitumen in water in the continuous phase. ![]() Since positives repel each other, all the droplets repel each other and remain as distinct bitumen drops in suspension. This imparts a positive charge to all the droplets. The cationic emulsifying agent functions similarly to the anionic the negative portion of the head floats around in the water leaving a positively charged head. The droplets migrate toward the cathode (negative electrode), and hence the emulsion is called cationic. The term cationic is derived from the migration of particles of bitumen under an electric field also. General Description of Cationic Bitumen Emulsion ![]()
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