Wearing Course Mixtures Prepared with High Reclaimed Asphalt Pavement Content Modified by Rejuvenators

Author(s):  
Stephan Büchler ◽  
Augusto Cannone Falchetto ◽  
Axel Walther ◽  
Chiara Riccardi ◽  
Di Wang ◽  
...  

This paper presents an experimental investigation on the combined use of high content of reclaimed asphalt pavement (RAP) and rejuvenators, for producing asphalt mixtures for wearing courses. First, the new Binder-Fast-Characterization-Test (Bitumen Typisierungs Schnell Verfahren in German) BTSV method, recently proposed in Germany, is used to determine the amount of rejuvenator required to design recycled mixtures for a specific RAP source. Then, a set of seven asphalt mixtures for wearing course is prepared with different amounts of RAP and with three types of rejuvenators. The BTSV procedure is further applied to evaluate the rheological properties of the binder extracted from the mixtures. Resistance to permanent deformation, stiffness, fatigue, and low temperature behavior tests are then performed to determine the material response. It is observed that the use of recycled material and rejuvenators results in similar or better deformation resistance, higher stiffness and enhanced low temperature properties, with an improved fatigue behavior, also for high RAP content, when compared to mixtures prepared with virgin material. These findings suggest the possibility of using rejuvenators for field tests on wearing courses.

Author(s):  
Ki Hoon Moon ◽  
Augusto Cannone Falchetto ◽  
Di Wang ◽  
Yun Su Kim

Using reclaimed asphalt material for rehabilitation and construction of new asphalt pavements is currently a common practice not only in view of the economic benefits associated with this process but also because of the reduced exploitation of natural resources. For this reason, road authorities have implemented recommendations and guidelines to regulate the use of reclaimed asphalt pavement (RAP) and other recycled materials such as industrial by-products. Nevertheless, the combined use of different recycled materials is not commonly addressed. In this paper, the effect of adding RAP and taconite (a mining by-product) on fatigue and low temperature properties of asphalt mixture was investigated with two different testing geometries: indirect tensile (IDT) and semi-circular bending (SCB). Fatigue behavior, creep stiffness, relaxation modulus, low temperature fracture energy, and fracture toughness were also evaluated, computed, and then compared. A more brittle behavior was observed for mixture prepared with RAP material, however, the mechanical performance was not significantly different for mixtures containing 20% RAP alone and in combination with 50% taconite compared with conventional asphalt mixtures designed with virgin material. This was not the case when RAP content was increased up to 50%, showing a substantially poorer response both in terms of fatigue and low temperature characteristics and suggesting the RAP had a dominant effect. The present exploratory research seems to support the idea of combining RAP and different industry by-products, such as taconite, as long as the RAP content is kept below a specific threshold.


2016 ◽  
Vol 43 (4) ◽  
pp. 343-350 ◽  
Author(s):  
Xuan Dai Lu ◽  
Mofreh Saleh

Using reclaimed asphalt pavement (RAP) increases the sustainability benefits and can enhance the performance of warm mix asphalt (WMA) compared to traditional hot mix asphalt (HMA). However, the RAP content is generally limited in WMA because adding high RAP content may reduce the performance of WMA. In this paper, the authors studied the possibility of incorporating high RAP content from 25 to 70% by mass of WMA by using Evotherm as an additive. Laboratory performance of WMA–RAP mixtures was characterized and compared to a control HMA in terms of moisture susceptibility, rutting resistance, and fatigue characterization. Test results showed that Evotherm greatly improved the moisture resistance of WMA–RAP mixtures compared to HMA. Increasing RAP content made WMA–RAP mixtures stiffer and enhanced the rutting resistance, but decreased the fatigue resistance of the mixtures. Therefore, the maximum RAP content needs to be determined to ensure balance between the fatigue and rutting characteristics of asphalt mixtures.


Author(s):  
Behnam Jahangiri ◽  
Hamed Majidifard ◽  
James Meister ◽  
William G. Buttlar

This study investigates the performance of eighteen different dense-graded asphalt mixtures paved in Missouri. The sections contain a wide range of reclaimed asphalt pavement (RAP) and recycled asphalt shingles (RAS), and different types of additives. The large number of sections investigated and the associated breadth of asphalt mixtures tested provided a robust data set to evaluate the range, repeatability, and relative values provided by modern mixture performance tests. As cracking is one of the most prevalent distresses in Missouri, performance tests such as the disk-shaped compact tension test (DC[T]) and Illinois flexibility index test (I-FIT) were used to evaluate the cracking potential of the sampled field cores. In addition, the Hamburg wheel tracking test (HWTT) was employed to assess rutting and stripping potential. Asphalt binder replacement (ABR) and binder grade bumping at low temperature were found to be critical factors in low-temperature cracking resistance as assessed by the DC(T) fracture energy test. Six sections were found to perform well in the DC(T) test, likely as a result of binder grade bumping (softer grade selection) or because of low recycling content. However, all of the sections were characterized as having brittle behavior by the I-FIT flexibility index. Service life and ABR were key factors in the I-FIT test. Finally, a performance-space diagram including DC(T) fracture energy and HWTT rut depth was used to identify mixtures with higher usable temperature interval (UTImix), some of which contained significant amounts of recycled material.


2021 ◽  
Vol 304 ◽  
pp. 124653
Author(s):  
Osvaldo Muñoz-Cáceres ◽  
Aitor C. Raposeiras ◽  
Diana Movilla-Quesada ◽  
Daniel Castro-Fresno ◽  
Manuel Lagos-Varas ◽  
...  

Sign in / Sign up

Export Citation Format

Share Document