Cold bituminous emulsion mixtures - laboratory mix design, trial section job site and monitoring

Id: 327

Authors: Jan Suda1, a / Jan Valentin1, b / Josef Žák1, c

1 Department of Road Structures, Czech Technical University in Prague, Faculty of Civil Engineering, Praha, Czech Republic




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Presently the road construction engineering focuses on technologies, which allow reducing energy demand of the structures to be built. This is closely linked to cutting the release of CO2 emissions and at the same time to the effort reducing costs for new structures or for rehabilitation works. Cold emulsified asphalt mixtures are a kind of road building material which is defined by using specific type of binder and ambient mixing temperatures. Typical is that their cohesion in the early stage after paving is rather lower and increases gradually during the curing period. Specific properties of these mixes support their use mainly for low-volume roads. These mixes have longer tradition in France and partly in the UK. In the Czech Republic very limited laboratory and practical experience are available for these mixtures. Until recent time there were even no technical specifications giving rules for design and use of these cold mixtures. This paper presents laboratory methodology which was used for cold emulsified asphalt mix design and describes results from such design. Additionally long-term assessment of experimentally evaluated characteristics is included as well. Since the real behavior of such mix in pavement structure cannot be with sufficient credibility described by laboratory tests a trial section was realized in 2014. This should bring additional verification of the experimental findings. For the trial section a low volume road was selected where existing pavement dimensions were known and data about daily average traffic were available. Reconstruction was expected with subsequent monitoring of the new structure with respect to traffic and climatic effects. The trial section was divided into 6 subsections with 5 different options of pavement design to evaluate effects of designed cold bituminous emulsion mixes in wearing and binder course. The mixes were designed in some of the options with 30 % of reclaimed asphalt (RAP). Experience from the first trial section in the Czech Republic and data of site monitoring are presented in this paper.

Asphalt, Cold Asphalt, Emulsions, Reclaimed asphalt pavement (RAP) Recycling, Testing