New experimental methods for characterizing formation and decay of foam bitumen
2015 (English)In: Materials and Structures, ISSN 1359-5997, E-ISSN 1871-6873Article in journal (Refereed) Published
Formation and decay of foam bitumen is a highly dynamic temperature dependent process which makes characterization difficult. In this research, new experimental tools were applied for characterizing the bitumen foam during the foaming process. Ultrasonic sensors were used for accurately monitoring the expansion and decay of foam bitumen as a function of time. Assessment of foam bitumen viscosity was performed using high frequency torsional rheometer and in situ observation by X-ray radiography. A high-speed camera was applied for examining the foam bitumen stream right at the nozzle revealing that foam bitumen at a very early stage contains fragmented pieces of irregular size rather resembling a liquid than foam. Moreover, infrared thermal images were taken for obtaining information on the in situ surface temperature of foam bitumen during the hot foaming process. The result showed that the average surface temperature of foam bitumen depends on the water content of the bitumen and bubble size distribution, 108 and 126 °C for 4 and 1 wt% (by weight) water content respectively. The residual water content in the decaying foam bitumen was determined by thermogravimetric analysis. The result demonstrated that residual water content depends on the initial water content, and was found to be between 38 and 48 wt% of the initial water content of 4–6 wt%. Finally, X-ray computed tomography was applied for examining the decay of foam bitumen revealing that the bubbles of foam bitumen remain trapped close to the surface of the foam bitumen.
Place, publisher, year, edition, pages
Foam bitumen characterization, Process monitoring, Thermal properties, X-ray analysis, Atmospheric temperature, Bubble columns, Computerized tomography, Decay (organic), High speed cameras, Surface properties, Thermodynamic properties, Thermogravimetric analysis, X ray analysis, X ray radiography, Bubble size distributions, Foam bitumens, Infrared thermal image, Initial water contents, New experimental method, Residual water content, Temperature dependent, X-ray computed tomography, Bituminous materials
IdentifiersURN: urn:nbn:se:kth:diva-177222DOI: 10.1617/s11527-015-0659-6OAI: oai:DiVA.org:kth-177222DiVA: diva2:873988
QC 201511252015-11-252015-11-172016-03-03Bibliographically approved