All around the globe efforts are being put forward to protect the environment. Currently, main emphasis is on reducing CO2 emissions in view of reducing the greenhouse effect. The European Union target has been defined to reduce the CO2 emissions between 1990 and 2010 by 15%. In France and Germany the Mitteldeutsche Hartstein-Industrie AG and Eurovia have developed a method to produce hot mix asphalt for road construction at lower temperatures. At the same time it was an objective that this asphalt should be able to be applied and compacted at the lower temperatures without any loss in workability and quality. The concept has been further developed and introduced also in the US. The reduction of production and application temperatures of hot mix asphalt means a significant environmental contribution in reducing energy consumption. And by reducing the fumes, a significant improvement of the working environment is obtained. The principle of the process is based on the special structure of aspha-min. This creates the ability to store crystalline water into the pores of the molecules. By adding this additive in the pre-heated mixture of sand and stone at the same time as the bitumen is being introduced, a water based vapour is created. This creates a controlled foaming effect, which then creates an increased volume of the binder in the mix. The extremely fine foam is creating micro pores, which again are creating a higher workability of the mix. Doing so the mix is obtaining a higher ability to be compacted, which was previously only possible at higher temperatures. For asphalt concrete mixing takes place between 130 and 140 degrees C. It is important that the additive particles are losing their water content in several steps and not all at once. Until cooling down to approximately 100 degrees C (212 degrees F), the possibility to compact the mix was observed. The workability of the mix is increased without changing the temperature. Furthermore no separation of the binder takes place in the mixinq process which means that good adhesion between binder and aggregates is obtained. All test sections which have been constructed so far demonstrate that this warm asphalt mix does not perform differently from regular hot asphalt. The paper describes results of test sections and reports on the results of laboratory investigations. For the covering abstract see ITRD E121480.

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    PO BOX 255
    BREUKELEN,     3620 AG
  • Authors:
    • Barthel, W
    • Marchand, J-P
    • von Devivere, M
  • Publication Date: 2004


  • English

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  • Accession Number: 00980913
  • Record Type: Publication
  • Source Agency: Transport Research Laboratory
  • ISBN: 90-802884-4-6
  • Files: ITRD
  • Created Date: Nov 3 2004 12:00AM