Quantitative Characterization of Binder Blending

Abstract

The current tendency in the asphalt paving industry is to increase the use of recycled asphalt pavement (RAP) and recycled asphalt shingles (RAS). However, a major concern that limits the use of RAP or RAS is the uncertainty about how much of the aged binder in RAP or RAS can be blended into virgin binder. Studies have focused on the diffusion between old and new binders. However, little research has been conducted to determine how much recycled binder could be mobilized and made available to coat aggregates. This study developed a laboratory procedure to quantify the rate at which aged binder was mobilized for recycled mixtures containing up to 80% RAP and 10% RAS. A new term, “large molecular size percentage (LMSP),” was derived from gel permeation chromatography testing and used to characterize recycled and virgin binders as well as their blends. Blending charts were generated for virgin–aged binder blends containing 0% to 100% RAP or RAS binder in LMSP. The relationship was found to be linear between LMSP and RAP or RAS binder content. An experiment was conducted to validate the method proposed for determining the mobilization rate. The results showed that the RAP binder mobilization rate decreased with the increase in RAP percentage in the mixture, which could be close to 100% at low RAP contents (10% and 20%); the rate dropped from 73% to 24% when the RAP percentage increased from 30% to 80%. For RAS, the mobilization rate reached a peak at 5% RAS content and then started to decrease with the increase in RAS content.

On the degree of binder activity of reclaimed asphalt and degree of blending with recycling agents

“…These concepts seem to be widely recognised by the scientific community, however the results of a literature review (Table 1) highlighted that practitioners have not yet achieved a general consensus on the terms related to the blending phenomena and authors use concepts and terms interchangeably. Amongst these: blending efficiency (Bowers, Huang, Shu, & Miller, 2014;Bowers, Moore, Huang, & Shu, 2014;Xu, Hao, Zhang, & Yuan, 2018), blending status (Zhao, Huang, Shu, & Woods, 2016), blending ratio (Delfosse, Drouadaine, Largeaud, & Dumont, 2016), rate of intermixing (Oliver, 2001), binder transfer (Zhang, Wen, & Hobbs, 2015), mobilization rate (Bressi et al, 2015;Ding, Huang, & Shu, 2018;Vassaux et al, 2018;Zhao, Huang, Shu, & Woods, 2015), meso-blending (Gundla & Underwood, 2015) and the most used terminology by far degree of blending (DoB) (Abd, Al-Khalid, & Akhtar, 2018;Al-Qadi et al, 2009;Booshehrian, Mogawer, & Bonaquist, 2013;Castorena, Pape, & Mooney, 2016;Cavalli, Partl, & Poulikakos, 2017;Coffey, Dubois, Mehta, & Purdy, 2013;Gaitan et al, 2013;Kriz et al, 2014;Liphardt, Radziszewski, & Król, 2015;Mogawer, Booshehrian, Vahidi, & Austerman, 2013;Mogawer et al, 2012;Navaro et al, 2012;Norton et al, 2014;Rinaldini, Schuetz, Partl, Tebaldi, & Poulikakos, 2014;Shirodkar et al, 2013Shirodkar et al, , 2011Stephens, Mahoney, & Dippold, 2001). (Vassaux et al, 2019) "Blend" presents the ability of two components to create a homogenous product where the chemical composition is identical everywhere at the scale observation of the study.…”

“…Furthermore, analysing the many factors identified, it was recognised that some are linked to the design and manufacturing of the asphalt mixture containing RA (Table 2), while some others are strictly related to the RA (Table 3). Kriz et al, 2014;Lo Presti et al, 2015;Nahar et al, 2013;Navaro et al, 2012;Oliver, 2001;Rad, Sefidmazgi, & Bahia, 2014;Stephens et al, 2001;Zhang et al, 2015;Zhao et al, 2015).…”

Technologies and Principles of Hot Recycling and Investigation of Preheated Reclaimed Asphalt Pavement Batching Process in an Asphalt Mixing Plant

“…Recent theoretical and practical achievements enable the recycling of up to 100% of RAP, of course, we need to evaluate that the studies were conducted in ideal and lab-controlled conditions [44,45]. RAP inhomogeneity has a huge impact on its maximum permitted percentage in a recycled RHMA.…”

Performance and Environmental Evaluation of Stabilized Base Material with Strontium Slag in Low‐Volume Road in China

“…Plenty of research efforts have been conducted on the impact of some waste materials (e.g., RAP, GTR, and waste concrete and brick) on the performance of the roads through laboratory and field tests. For example, the researchers reported that RAP improved the rutting resistance [3][4][5][6][7][8] and GTR improved the resistance to permanent deformation and cracking of the asphalt mixtures [9][10][11][12][13]. Jia et al [14] presented the use of construction and demolition wastes in LVRs and indicated using them in the base and subbase is feasible for low-volume roads if the mix design is appropriate.…”