scholarly journals A Review on the Durability of Recycled Asphalt Mixtures Embraced with Rejuvenators

2021 ◽  
Vol 13 (16) ◽  
pp. 8970
Author(s):  
Zaid Hazim Al-Saffar ◽  
Haryati Yaacob ◽  
Herda Yati Katman ◽  
Mohd Khairul Idham Mohd Satar ◽  
Munder Bilema ◽  
...  
Keyword(s):  
Asphalt Pavement ◽  
Climatic Conditions ◽  
Asphalt Mixtures ◽  
Reclaimed Asphalt Pavement ◽  
Extensive Literature ◽  
Recycled Asphalt ◽  
Reclaimed Asphalt ◽  
Traffic Loads ◽  
Aged Asphalt ◽  
Future Challenges

Reclaimed asphalt pavement (RAP) has received much attention recently due to its increased use in hot mix asphalt (HMA) pavements to enhance pavement sustainability. The use of aged asphalt in RAP, which is highly oxidised and has lost its properties due to exposure to traffic loads and climatic conditions throughout its lifespan, can cause asphalt mixtures to stiffen and embrittle, thus negatively affecting the behaviour of asphalt mixtures. This issue may be resolved by including rejuvenating agents that can restore both physical and rheological properties of aged asphalt by increasing maltene fractions and decreasing asphaltene. However, the high restoration capacity of any kind of rejuvenating agent does not assure the durability of restored aged asphalt. This study explored the performance and durability of rejuvenated asphalt mixtures embedded with several types of rejuvenators identified from the extensive literature review. The study serves as a significant reference to predict future challenges in rejuvenating aged asphalt.

scholarly journals Quantitative Analysis of the Blending Degree of Virgin and RAP Binders in Recycled Asphalt Mixtures with a High RAP Content

2018 ◽  
Vol 8 (12) ◽  
pp. 2668 ◽  
Author(s):  
Zhen Yang ◽  
Guoyi Zhuang ◽  
Xiaoshu Wei ◽  
Jintao Wei ◽  
Huayang Yu ◽  
...  
Keyword(s):  
Asphalt Pavement ◽  
Asphalt Mixtures ◽  
Reclaimed Asphalt Pavement ◽  
Structural Index ◽  
Comprehensive Understanding ◽  
Recycled Asphalt ◽  
Reclaimed Asphalt ◽  
Standard Curve ◽  
Study Results ◽  
Mineral Additives

Recycled asphalt mixtures (RAM), which are prepared by blending reclaimed asphalt pavement (RAP), virgin bitumen and mineral additives, provide a variety of advantages, including resource recycling, reductions in costs, and reduced negative environmental impacts. However, multiple agencies have expressed concerns about the utilization ratio of RAP; thus, a comprehensive understanding of the blending degree of virgin and RAP binders in RAM would be significantly helpful for promoting the application of RAP. This study aims to quantitatively analyze the blending degree of virgin and RAP binders in RAM with high RAP contents. Carboxyl-terminated butadiene acrylonitrile (CTBN) was utilized as a tracer to mark the virgin bitumen; in addition, Fourier transform infrared (FTIR) spectroscopy was used to develop the structural index of CTBN (ICTBN). By establishing the standard curve between ICTBN and the CTBN content, the blending degree of virgin and RAP binders at different locations within RAM can be determined quantitatively. The study results indicate that the RAP binder was completely blended with the virgin bitumen in the outer RAP layer. However, the blending degree decreased with an increase in the RAP depth, and the blending degree in the inner RAP layer was only approximately half that which was found in the case of complete blending.

scholarly journals Experimental study of recycled asphalt mixtures with high percentages of reclaimed asphalt pavement (RAP)

2011 ◽  
Vol 25 (3) ◽  
pp. 1289-1297 ◽  
Author(s):  
Gonzalo Valdés ◽  
Félix Pérez-Jiménez ◽  
Rodrigo Miró ◽  
Adriana Martínez ◽  
Ramón Botella
Keyword(s):  
Experimental Study ◽  
Asphalt Pavement ◽  
Asphalt Mixtures ◽  
Reclaimed Asphalt Pavement ◽  
Recycled Asphalt ◽  
Reclaimed Asphalt

scholarly journals The Influence of Mixing Conditions on the Macro-Scale Homogeneity of Asphalt Mixtures Blended with Reclaimed Asphalt Pavement (RAP)

Materials ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4137
Author(s):  
Quan Liu ◽  
Markus Oeser
Keyword(s):  
Mechanical Performance ◽  
Design Method ◽  
Asphalt Pavement ◽  
Mixing Time ◽  
Asphalt Mixtures ◽  
Reclaimed Asphalt Pavement ◽  
Mixing Conditions ◽  
Recycled Asphalt ◽  
Reclaimed Asphalt ◽  
Macro Scale

The homogeneity of asphalt mixtures blended with reclaimed asphalt pavement (RAP) is affected by many factors. Due to the complicated compositions of recycled asphalt mixtures, the inhomogeneity issue might cause insufficient mechanical properties of asphalt mixtures, even though a design method was appropriately adopted. Therefore, it is of great significance to study the influence of mixing conditions on the homogeneity of asphalt mixtures blended with RAP materials. This study focused on the macro-scale homogeneity of produced asphalt mixtures. Specifically, asphalt mixtures incorporated with 40% RAP content were produced in a laboratory using different mixing times and mixing temperatures. A multi-direction indirect tensile stiffness modulus (ITSM) test was proposed to quantify the homogeneity of produced samples. In addition, the digital image processing (DIP) method was used to identify the distribution of aggregates and RAP binder. The results indicated that the influence of mixing time on the macro-homogeneity of asphalt mixtures indicated that a longer mixing time was favorable for the material dispersion. The influence of mixing temperature mainly rested on two perspectives. One was that the temperature variation induced the change of binder viscosity. The other was that the temperature influences the diffusion process between RAP binder and new bitumen, which further affected the mechanical performance of produced asphalt mixtures.

scholarly journals Laboratory comparative assessment of warm and hot mixes Asphalt containing reclaimed Asphalt pavement

2020 ◽  
Vol 8 (2) ◽  
pp. 15-26
Author(s):  
Hasan H Joni ◽  
Aqeel Y M Alkhafaji
Keyword(s):  
Asphalt Pavement ◽  
Asphalt Mixture ◽  
Warm Mix Asphalt ◽  
Asphalt Mixtures ◽  
Reclaimed Asphalt Pavement ◽  
Moisture Resistance ◽  
Recycled Asphalt ◽  
Reclaimed Asphalt ◽  
Marshall Stability ◽  
The Impact

Warm mix Asphalt (WMA) could be mixed and used in paving at low temperatures to minimize the consumption of energy and the emissions of greenhouse gas. Recycled Asphalt pavement (RAP) could save Asphaltic cement and aggregate, which could achieve the better effects of recycling. However, both of the two WMA and RAP technologies have some deficiencies. Warm mix Asphalt and Reclaimed Asphalt pavement (WMA-RAP) technique may solve these issues and deficiencies when they are utilized together. This study investigated the implementations of WMA-RAP and its impacts on the performance of the Asphalt mixture. Under the framework of this study, four percentages of RAP (0%, 20%, 30%, and 40%) were added to the hot mix Asphalt (HMA) and WMA containing 4% Sasobit to study the impact of increasing RAP content on Marshall stability and moisture resistance of Asphalt mixtures. In summary, the Marshall stability of HMA and WMA mixtures is higher than the control mixtures. A small decrease in moisture resistance of both (HMA and WMA) containing RAP comparing to control mixtures Asphalt was observed, as shown by reduced the tensile strength ratios (TSR), but it is still much higher than the minimum of 80%.

A review on rejuvenating materials used with reclaimed hot mix asphalt

2020 ◽  
Author(s):  
Zaid Hazim Al Saffar ◽  
Haryati Yaacob ◽  
Mohd Khairul Idham ◽  
Mhmood Khleel Saleem ◽  
JAU CHOY LAI ◽  
...  
Keyword(s):  
Asphalt Pavement ◽  
Reclaimed Asphalt Pavement ◽  
Construction Technology ◽  
Reclaimed Asphalt ◽  
Aged Asphalt ◽  
Future Challenges ◽  
Materials Used ◽  
Pavement Construction ◽  
Optimal Approach ◽  
Pavement Service Life

In recent years, flexible pavement construction technology has relied heavily on the use of reclaimed asphalt pavement (RAP). However, the brittle nature of RAP, which stems from the use of an aged asphalt, has introduced numerous complexities into the process, with important implications to pavement service life. The properties of the aged asphalt can be rejuvenated to improve the performance and the behavior of RAP mixtures. This paper presents a review of past works that have used rejuvenating materials with RAP, including their benefits and drawbacks, as well as the optimal approach to increase RAP content in asphaltic mixtures. The method of rejuvenating aged asphalt and the mechanism of rejuvenation are also reviewed. The findings of this review can be used to predict the current and future challenges in the regeneration of RAP mixtures using rejuvenating materials.

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