Environmental benefits from resource-saving of long-life asphalt pavement

Author(s):  
F.X. Zhao ◽  
H.L. Wang ◽  
X.M. Li
2021 ◽  
Vol 6 (3) ◽  
Author(s):  
Mohammad Ashiqur Rahman ◽  
Rouzbeh Ghabchi ◽  
Musharraf Zaman ◽  
Syed Ashik Ali

AbstractDespite significant economic and environmental benefits, performance of warm mix asphalt (WMA) containing reclaimed asphalt pavement (RAP) remains a matter of concern. Among the current WMA technologies, the plant foaming technique (called “foamed WMA” in this study) has gained the most attention, since it eliminates the need for chemical additives. In the present study, the laboratory performance, namely rutting and moisture-induced damage potential of foamed WMA containing RAP were evaluated and compared with those of similar hot mix asphalt (HMA) containing identical amount of RAP. Dynamic modulus, Hamburg wheel tracking (HWT) and flow number tests were performed to assess the rutting resistance of the mixes. Also, stripping inflection point from HWT tests and tensile strength ratio after AASHTO T 283 and moisture induced sensitivity test (MIST) conditioning were used to evaluate the moisture-induced damage of asphalt mixes. It was found that MIST conditioning effectively simulates the moisture-induced damage and can capture the propensity of asphalt mixes to moisture damage more distinctly compared to AASHTO T 283 method due to application of cyclic loadings. The foamed WMA was found to exhibit higher rutting and moisture-induced damage potential due to lower mixing and compaction temperatures compared to HMA. However, the increase in RAP content was found to reduce rutting and moisture-induced damage potential for WMA. Therefore, the lower stiffness of foamed WMA may be compensated with the addition of stiffer binder from RAP.


2013 ◽  
Vol 649 ◽  
pp. 242-245 ◽  
Author(s):  
Alina Mihaela Nicuţă

The evaluation of energy savings in the area of transport infrastructure entails a complex characterization of factors, attitudes and consequences. In the frame of energy saving approach, must be identified sustainable alternatives and solutions for road asphalt pavements production and exploitation. Finding innovative materials is one major objective in this process. In the present paper has been carried out an evaluation of the energetically and environmental benefits of warm mix asphalt (WMA) compositions that incorporate reclaimed asphalt pavement (RAP) and their contribution to roads sustainable development. For a proper analysis and reliable results, have been used the Life Cycle Assessment methodology and asPECT software. WMA integrating RAP are known as energy – saving and environmentally friendly asphalt roads pavements. Analyzed in a comparative perspective with hot mix asphalt (HMA) incorporating RAP, WMA would gain in results due to the decrease in mixing and compaction temperature, energy consumption and emissions but also to the increase in durability, quality and performance. The results of this comparison intended to point out an alternative that would provide an increase in the sustainability of the transport infrastructure sector.


2018 ◽  
Author(s):  
Xinquan Xu ◽  
Hao Li ◽  
Chuanhai Wu ◽  
Shanqiang Li
Keyword(s):  

Materials ◽  
2020 ◽  
Vol 13 (9) ◽  
pp. 2169
Author(s):  
Song Li ◽  
Rui Xiong ◽  
Jiahui Zhai ◽  
Kaiyin Zhang ◽  
Wenyu Jiang ◽  
...  

In order to ensure the safety of traffic, asphalt pavement is commonly required to utilize aggregates with excellent anti-abrasion property. This results in the lack of high-quality aggregates. The incorporation of solid waste in the aggregates is regarded as a high potential alternative for solving this problem. Since its material properties, such as rough surface, high Polished Stone Value (PSV) and the excellent adhesion property of asphalt, Basic Oxygen Furnace (BOF) slag can effectively improve the skid resistance of asphalt mixtures. First, the material properties of BOF slag are reviewed in this study. Then, the skid resistance of asphalt mixtures and aggregates are commendably evaluated by the Polished Stone Value test, Wehner/Schulze Tester, Aachen Polishing Machine, British Pendulum Test and Sand Patch test. The physical and mechanical properties of BOF slag play a key role in asphalt mixtures. This review found that the skid resistance mechanism of the BOF slag asphalt mixture is governed by factors such as BOF slag properties, incorporation methods and gradation types. Finally, the economic and environmental benefits of BOF slag asphalt mixtures were discussed. In addition, the function of gas catalysis and the melting of ice and snow can be added to the BOF slag asphalt mixture for a cleaner development in engineering. Furthermore, the existing problems, research directions and corresponding measures in this field are directed towards more durable and functional asphalt pavement construction.


Author(s):  
Jian-Shiuh Chen ◽  
Han-Chang Ho ◽  
Yen-Yu Lin

The two primary factors that drive the use of reclaimed asphalt pavement (RAP) are economic savings and environmental benefits. However, highway agencies are concerned about the use of a high percentage of RAP in asphalt pavements. This study addressed issues related to the production, construction, properties, and performance of asphalt pavements that contain high percentages of RAP. Mixtures that contained up to 40% RAP were successfully designed, produced, and constructed after proper procedures were followed and attention to detail was paid during design, production, and construction. A separate drum for drying and heating RAP, called a parallel heating system, was used to produce high RAP content asphalt mixtures in a batch plant. Rejuvenating agents were mixed directly in a surge bin to allow the rejuvenator enough time to diffuse into aged RAP binder. Comprehensive laboratory tests were performed to evaluate the air voids, the resilient modulus, the rut depth, and the Cantabro weight loss of asphalt mixtures with high RAP content. A test road was constructed in 2014 to monitor how high RAP asphalt pavements would perform under real traffic and environmental conditions. An in-depth investigation was conducted of pavement performance, including cracking, friction, and rutting. The engineering properties of plant-produced mixtures and field cores were well correlated with the pavement performance of the test road. Test results indicated that high RAP content asphalt mixtures could perform as satisfactorily as those produced with virgin materials to meet in-service requirements.


Author(s):  
Shawn S. Hung ◽  
Mohammad Zia Alavi ◽  
David Jones ◽  
John T. Harvey

Rubberized hot-mix asphalt (RHMA) has been widely used in construction projects by the California Department of Transportation (Caltrans) for the environmental benefits of its recycled waste tires and for its improved fatigue and reflective cracking resistance. Currently, Caltrans does not permit the use of reclaimed asphalt pavement (RAP) in any gap- or open-graded rubberized asphalt mixes. However, given the cost and environmental benefits of RAP to replace portions of required virgin binder and aggregates in conventional mixes, interest is growing in the addition of some RAP to RHMA mixes as well. This study investigated concerns about this proposed practice. Three phases of laboratory testing (i.e., asphalt binder testing, fine aggregate matrix mix testing, and full-graded mix testing) were conducted to evaluate the effects of the addition of RAP into new RHMA mixes. The results indicated that the gap-graded aggregate structure of RHMA might limit the amount of RAP that could be used in the mix. Only 10% RAP by binder replacement could be achieved for the mix tested in this study, but the other specified volumetric requirements were still met. Replacement of a portion of asphalt rubber binder with age-hardened RAP binder increased the binder stiffness at low and high temperatures, which indicated enhanced rutting performance but diminished low-temperature cracking performance. Test results from full-graded mixes indicated similar trends, with improved rutting performance with the addition of RAP but also with significantly poorer fatigue and reflective cracking resistance.


Materials ◽  
2020 ◽  
Vol 13 (7) ◽  
pp. 1582 ◽  
Author(s):  
Ghulam Yaseen ◽  
Imran Hafeez

Asphalt is the most commonly used material for pavement construction around the world, and therefore, it is vital to acquaint a practice that restores the reclaimed asphalt pavement (RAP) binder properties to the required level of performance by adding proper rejuvenators. However, a rejuvenator may perform better in the early stages of its application but may not necessarily perform better in the long run. The aim of this study is to assess the rejuvenation effect on the aging resistance of RAP binder in long-life performance through applying artificial aging. In this study, base virgin binder of pen grade 60/70 and RAP binder rejuvenated with Cereclor were subjected to artificial aging to simulate the short- and long-term aging effects. Penetration, softening point, ductility, and viscosity; saturates, aromatics, resins, and asphaltene (SARA) fractionation; and Fourier-transform infrared (FTIR) spectroscopy, bending beam rheometer (BBR), and dynamic shear rheometer (DSR) tests were conducted to evaluate the potential improvements in various properties of RAP binder. The results indicated that the physical, fractional composition, rheological, and aging resistance of RAP binder improved through the rejuvenation mechanism. Therefore, the rejuvenator improved the chemical structure through re-balancing the constituents in the colloidal system, even after long-term re-aging, which proves it to be an aging-resistant binder. Furthermore, it has been concluded that Cereclor has substantial rejuvenation potential even after applying artificial aging, and it can be utilized in pavement recycling to achieve long-life performance. Furthermore, the results depict good correlations between the physical, rheological, and chemical parameters of virgin and RAP binder.


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