Laboratory characterization of cold mix treated with bitumen emulsion

In a political context in which energy and environmental stokes become increasingly stron, road engineering evolves to energy savings and environmentally friendly practices. In this context, cold mixes treated with bitumen emulsion appear as suitable techniques. Cold mix design and manufacture are empirical and usually controlled thanks to local competences. Based on experimental principles, these methods do not provide fundamental answers to issues such as mixing, transport, workability, compactability, mechanical resistance and coating quality. A research program is started at LCPC with the collaboration of the French Road and Bridges Regiional Laboratories to answer this waiting. An emulsion treated gravel (GE 0/14) with a residual bitumen content of 4,5% ws implemented on a French experimental jobsite in October 2006. Loose jobsite materials and samples manufactured in Laboratory with materials (aggregates and emulsion) coming from jobsite have been characterized. Traditional tests used in the French hot mix design methodology as well as more specific techniques such as triaxial apparatus for cyclic loadings, used to assess mechanical characteristic of unbound granular materials, have been used. This paper presents current normative and also innovating properties linked to implementation behaviour, rheological behaviour and time-dependance (cohesion increase) of emulsion treated gravel