Asphalt emulsion formulation: State of the art of formulation, properties and results of HIPR emulsions

As a way to make pavements more economic, less polluting, and with lower energy consumption bitumen emulsions can be used. The formulation of bitumen emulsions is a complex task and they are usually produced using colloid mills. This method presents several limitations; the maximum bitumen concentration of the dispersed phase, 69%, being the most significant. The HIPR (High Internal Phase Ratio) method must be used for higher bitumen concentrations. With this second method, apart from it being possible to obtain concentrated emulsions, with a volume fraction higher than 70%, it is possible to control the distribution and average droplet diameter of the emulsion. This control is achieved by changing variables such as the volume fraction, the concentration and type of surfactant and the temperature of the dispersed phase, the type of bitumen used, and mechanical variables such as the rotational speed and time employed. The current study aims to review the state-of-the-art of the manufacture of bitumen in water emulsions, with a special emphasis on the concentrated bitumen emulsions manufactured following the HIPR method. (C) 2019 Elsevier Ltd. All rights reserved.