Powder emulsions has been known for a long time. I am sure most of us remember powdered milk. What if it is possible to apply this technology to make bitumen emulsion used in road construction then it will revolutionize the bitumen emulsion industry. It will be add convenience bitumen transportation to remote areas and it will add convenience in use.
To make dry road bitumen emulsion you a special polymer must be present. The polymer allows encapsulation and water elimination. Some companies are working to solve this problem since 1995 and have achieved considerable success in areas of agricultural chemistry and pharmacology. The developed technologies and processes may apply to the production of dry road bitumen emulsion.
It is possible to achieve this using a typical bitumen emulsion. A required extra step introduces an aqueous polymer into the mix and then dries the substance until capsule-like particle is formed. The polymer resembles each capsule contains a liquid droplet.
Long-term study of the physicochemical emulsion properties suggests synthesis of a hydrophilic polymer polyacrylate that has a low viscosity. It consists of hydrophobic substances, which do not inhibit the water solubility. Polyacrylate was the material that helped in making dry road bitumen emulsion production.
During the drying process, it is important to maintain minimal ratio of 10 between the granule size and emulsion droplet size.
It should be noted that the drying process has little or no effect on the bitumen emulsion properties in fact in some cases they actually improve. For example, the stability of the dry emulsion increases because the encapsulation process prevents its decay.
Another advantage of these materials is the possibility of mixing two or three emulsions that under normal conditions are not compatible with each other.
The general principle behind obtaining the dry road bitumen emulsion can be described as follows: first, the polymer is added directly to typical emulsion, then it is dried by one of available methods (e.g., dry spay), and the resulting powder is collected and stored. It at any time the powder may be dispersed in water, and restored to the original emulsion condition for later use.