Abstract
This paper investigates the feasibility of using silica fume to enhance the rheological properties of asphalt binder. It has been widely reported that asphalt binder oxidation is one of the phenomena that reduces the service life of asphalt pavement by negatively impacting its rheological properties. This in turn can lead to a more brittle pavement which is more prone to cracks due to thermal stress and traffic loading. Prior research has shown that introduction of nano-silica to asphalt can reduce asphalt oxidation aging; however, the main challenge with use of nano-silica found to be agglomeration of nano-particles to form micro size clusters which can reduce nano-silica effectiveness while making asphalt binder more susceptible to shear. Therefore, this paper studies effectiveness of using silica fume to reduce asphalt oxidative aging while alleviating agglomeration issue. To do so, various percentages of silica fume was introduced to a base asphalt binders and the rheological properties and high temperature performance of each specimen was evaluated by measuring the rotational viscosity and complex shear modulus before and after oxidative aging. Analysis of the experimental results showed that silica fume reduced asphalt aging index significantly; in addition the temperature susceptibility of asphalt binder was reduced as the percentage of silica fume increased. The flow of modified mixtures increased and the loss of stability of samples decreased as the amount of silica fume increased. The positive effect of silica fume on base asphalt’s rheological properties could be attributed to the high surface area and the low degree of agglomeration of the silica fume due to their high polarity. This in turn could improve silica fume’s blending properties resulting in a uniformly distributed silica fume modified matrix with enhanced oxidative aging resistance.
Highlights
Worldwide annual consumption of asphalt is 150 million tons which makes it an $80 billion dollars industry in 2013
Oxidative aging of asphalt binder is expedited when heated at the application temperature and mixed with stone aggregates; this usually is accompanied by significant loss of volatiles compounds while giving rise to carbonyl and sulfoxide compounds in asphalt (Lu and Isacsson, 2002)
To reduce the oxidation rate of asphalt binder, silica fume was added to the base asphalt binder PG 64-22 at various percentages
Summary
Worldwide annual consumption of asphalt is 150 million tons which makes it an $80 billion dollars industry in 2013. Other studies have used nano-silica to achieve a highly polar surface and reported that nano-silica can be very effective in reducing the aging rate while enhancing resistance to rutting and cracking. Modifiers such as silica fume have the capability to enhance the aging resistance of asphalt binder as well as extend the asphalt’s high- and low-temperature workability. To achieve such improvements, it is critical to ensure uniform blending of nano-silica into the asphalt matrix. This study investigates the effectiveness of silica fume in the form of a granulated industrial waste with highly polar surface area to enhance blending and improve asphalt oxidation resistance
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callMore From: American Journal of Engineering and Applied Sciences
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
