Asphalt Emulsion Technolgy: Review of Asphalt Emulsion Residue Procedures. Transportation Research Circular E-C122

摘要

Bituminous emulsion paving materials continue to be a challenging area of research and practical applications. Transportation Research Circular E-C102: Asphalt Emulsion Technology presented an overview of asphalt emulsion technology covering its chemistry, manufacturing, and applications. Continuing with this international sharing of asphalt emulsion technology from researchers and practitioners, this circular reviews methods used to recover the residue of bituminous emulsions. While there is consensus on standard tests to be performed on the recovered asphalt residue, there is little or no consensus on procedures to remove water from an asphalt emulsion. This is particularly true when it comes to the recovery of residue from a polymer-modified emulsion. Today, it is well accepted that the high-temperature recovery procedures, such as distillation, used to obtain the residue from non-polymermodified emulsions is not suitable for polymer-modified emulsions. It has been shown that high recovery temperatures and extended recovery times degrade the polymer significantly, hence measurement of residue property gives misleading results on its ultimate performance. The hot-mix asphalt industry has accepted that measuring rheological properties of asphalt binders tells something about their performance. Therefore, many of the traditional tests have been abandoned as specifications for asphalt binders. Conversely, the traditional tests continue to be used for asphalt emulsions. There have been some attempts to perform rheological tests on the asphalt emulsion residue. However, the results were questioned because of the recovery procedure used. While instrumentation exists to perform rheological tests, the stumbling block for the asphalt emulsion industry to implement such a rheological approach is the lack of an acceptable recovery method that would be suitable to all emulsions. With modern instrumentation it is not hard to imagine one instrument whose temperature can be programmed for the particular type of emulsion and that can be automated, making measurement of rheological measurements simple provided the residue for testing can be obtained.