Change search
ReferencesLink to record
Permanent link

Direct link
Influence of foaming water content on foam asphalt mixtures
KTH, School of Architecture and the Built Environment (ABE), Transport Science.
KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Materials.
2015 (English)In: Construction and Building Materials, ISSN 0950-0618, Vol. 85, 65-77 p.Article in journal (Refereed) Published
Abstract [en]

Warm mix asphalt technology using foamed bitumen is being used widely despite the fact that high air void content and poor coating of large aggregate remain major drawbacks require enhancement. This paper manly focuses on the investigation of water content influence on the foamed bitumen and the asphalt mixture. Influence of the water content in combination with compaction temperature has been investigated using gyratory compaction method. AC11N foam asphalt mixture is produced in the lab using lab foamer. Marshall stability and indirect tensile test was used to evaluate the foam asphalt mixture performance. The investigation revealed that the Marshall stability of foam asphalt mixture is highly influenced by compaction temperature compared to water content. Moreover, increasing the water content helps in coating large aggregates when the mixture is produced at low temperature, nevertheless using high water content reduces the Marshall stability to certain extent. In addition the amount of water trapped in the mixture after the mixing process was determined using thermogravimetric analysis. The amount of water remaining in the asphalt mixture is less than 1% relative to the bitumen mass.

Place, publisher, year, edition, pages
2015. Vol. 85, 65-77 p.
Keyword [en]
Foamed bitumen, Water content, Asphalt mixture, Laboratory tests, Thermogravimetric analysis
National Category
Materials Engineering
URN: urn:nbn:se:kth:diva-169242DOI: 10.1016/j.conbuildmat.2015.03.071ISI: 000354139400008OAI: diva2:822040

QC 20150616

Available from: 2015-06-16 Created: 2015-06-12 Last updated: 2016-03-03Bibliographically approved
In thesis
1. Morphology Characterization of Foam Bitumen and Modeling for Low Temperature Asphalt Concrete
Open this publication in new window or tab >>Morphology Characterization of Foam Bitumen and Modeling for Low Temperature Asphalt Concrete
2016 (English)Doctoral thesis, comprehensive summary (Other academic)
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.

Place, publisher, year, edition, pages
Stockholm: KTH Royal Institute of Technology, 2016. xiv, 134 p.
TRITA-BYMA, ISSN 0349-5752 ; 2016:1
foam characteristics, evolution of foam bitumen bubbles, image analysis, modeling rising of bubble, foam asphalt mixture
National Category
Infrastructure Engineering
Research subject
Transport Science
urn:nbn:se:kth:diva-183105 (URN)978-91-7595-865-1 (ISBN)
Public defence
2016-04-01, Kollegiesalen, Brinellvägen 8, KTH, Stockholm, 13:00 (English)

QC 20160303

Available from: 2016-03-03 Created: 2016-02-29 Last updated: 2016-03-09Bibliographically approved

Open Access in DiVA

No full text

Other links

Publisher's full text

Search in DiVA

By author/editor
Hailesilassie, Biruk W.Partl, Manfred N.
By organisation
Transport ScienceBuilding Materials
In the same journal
Construction and Building Materials
Materials Engineering

Search outside of DiVA

GoogleGoogle Scholar
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

Altmetric score

Total: 35 hits
ReferencesLink to record
Permanent link

Direct link