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New experimental methods for characterizing formation and decay of foam bitumen
KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Transportvetenskap, Väg- och banteknik.
KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Byggvetenskap, Byggnadsmaterial. EMPA, Swiss Federal Laboratories for Material Science and Technology, Switzerland.
2015 (engelsk)Inngår i: Materials and Structures, ISSN 1359-5997, E-ISSN 1871-6873Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

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.

sted, utgiver, år, opplag, sider
2015.
Emneord [en]
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
HSV kategori
Identifikatorer
URN: urn:nbn:se:kth:diva-177222DOI: 10.1617/s11527-015-0659-6OAI: oai:DiVA.org:kth-177222DiVA, id: diva2:873988
Merknad

QC 20151125

Tilgjengelig fra: 2015-11-25 Laget: 2015-11-17 Sist oppdatert: 2017-12-01bibliografisk kontrollert
Inngår i avhandling
1. Morphology Characterization of Foam Bitumen and Modeling for Low Temperature Asphalt Concrete
Åpne denne publikasjonen i ny fane eller vindu >>Morphology Characterization of Foam Bitumen and Modeling for Low Temperature Asphalt Concrete
2016 (engelsk)Doktoravhandling, med artikler (Annet vitenskapelig)
Abstract [en]

Development of new asphalt technologies to reduce both energy consumption and CO2 production has attracted great interest in recent years. The use of foam bitumen, as one of them, is attractive due to the low investment and production cost. Formation and decay of foam bitumen is a highly dynamic temperature dependent process which makes characterization difficult. In this thesis, new experimental tools were developed and applied for characterizing the foam bitumen during the hot foaming process. 

One of the main goals of this study was to improve understanding and characterization of the foam bitumen formation and decay. X-ray radiography was used to study the formation and decay of foam bitumen in 2D representation. The results demonstrate that the morphology of bubble formation depends on the types of bitumen used. Moreover, theoretical investigation based on the 3D X-ray computed tomography scan dataset of bubble merging showed that the disjoining pressure increased as the gap between the bubbles in the surface layer (foam film) decreased with time and finally was ruptured. 

 Examining the foam bitumen stream right at the nozzle revealed that foam bitumen at a very early stage contains fragmented pieces of irregular size rather resembling a liquid than foam. The result from thermogravimetric analysis demonstrated that residual water content depends on the initial water content, and was found to be between 38 wt% and 48 wt% of the initial water content of 4 wt% to 6 wt%.

Moreover the influence of viscosity and surface tension on bubble shape and rise velocity of the bubbles using level-set method was implemented in finite element method. The modeling results were compared with bubble shape correlation map from literature. The results indicated that the bubble shapes are more dependent on the surface tension parameters than to the viscosity of the bitumen, whereas the bitumen viscosity is dominant for bubble rising velocity.

sted, utgiver, år, opplag, sider
Stockholm: KTH Royal Institute of Technology, 2016. s. xiv, 134
Serie
TRITA-BYMA, ISSN 0349-5752 ; 2016:1
Emneord
foam characteristics, evolution of foam bitumen bubbles, image analysis, modeling rising of bubble, foam asphalt mixture
HSV kategori
Forskningsprogram
Transportvetenskap
Identifikatorer
urn:nbn:se:kth:diva-183105 (URN)978-91-7595-865-1 (ISBN)
Disputas
2016-04-01, Kollegiesalen, Brinellvägen 8, KTH, Stockholm, 13:00 (engelsk)
Opponent
Veileder
Merknad

QC 20160303

Tilgjengelig fra: 2016-03-03 Laget: 2016-02-29 Sist oppdatert: 2016-03-09bibliografisk kontrollert

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