Improvement of formulation methodology to optimize cold bituminous mixes

Cold bituminous mixes as emulsion treated materials are considered as high potential development products for the future safe and environmentally friendly road materials. Laboratory asphalt mix design methodologies are aimed at predicting on site behaviour and determining the mechanical characteristics of mixes. The emulsion design method cold mixes is currently based on specifications which are used for hot mix asphalt. In some cases, laboratory behaviour fail to predict the on site one. In order to achieve laboratory optimization rules and design pavements including cold asphalt mixes, complementary test methods are required. This paper presents a methodology based on four tests to improve emulsion treated materials mix design and optimise mix components choice and proportioning by : - assessing the coating quality and the mix consistency, - monitoring the mix hardening versus time, - characterizing the chemical reactivity of aggregates in presence of cationic bituminous emulsion, - assessing the mix ability to drain water from manufacturing up to implementation