Cold mix design: A rational approach based on the current understanding of the breaking of bituminous emulsions

ABSTRACT The general environmental concern all over Europe constitutes a strong incentive towards cold technologies and therefore designing cold mixes with bituminous emulsion has become a key subject in the last few years. However, cold mix design is not an easy task and necessitates first a good knowledge of the physicochemical aspects involved in cold mix properties, from the characterization of the emulsions to the final application with a given aggregate. Therefore, this paper presents an up-to-date description of the chemistry and physics of bituminous emulsions and their interactions with mineral matter, based on recent published results. In particular, the key parameters involved in the breaking process are highlighted. From this overall picture, a general method to design cold mixes is proposed. This highlights the work needed in terms of testing and standardization in order to develop a rational mix design method, without which further development of cold technologies will be difficult.