Laboratory Performance of Asphalt Emulsion Treated Base for Cold Regions Applications

摘要

Asphalt emulsions are one of the alternatives for stabilizing base layers. The use of asphalt emulsion treated mixtures can be cost effective especially in cold regions where supplying hot mix is not economical. However, in cold climates emulsion aggregate mixtures show low strength at early ages and require a longer curing time to develop breaking of asphalt emulsions throughout the aggregates. The breaking period depends on the rate of water loss from the mixture which is impacted by ambient temperatures. Type of asphalt emulsion, curing temperature, curing time and moisture content are four significant factors in early age development of engineering properties of the emulsion base aggregate mixture. In this study, a proposed dense-graded gravel base material was treated with an anionic slow setting emulsion with low viscosity (SS-1). In order to evaluate early curing, one set of samples was cured for 7 days at 5℃ and another set was cured at 24 ℃. Dynamic resilient modulus and permanent deformation tests were performed to assess the effect of curing and temperature on stiffness and resistance to the repeated traffic load. The study showed that high resilient modulus and low deformation values were attained for 7 days curing at 24℃. The low temperature slows the breaking process of the emulsion and causes the emulsion aggregate mixtures to have a lower resistance to repeated loading.