A study on the effect of rejuvenators in reclaimed asphalt pavement based stone mastic asphalt mixes

2019 ◽  
Vol 12 (1) ◽  
pp. 9-16 ◽  
Author(s):  
L. Durga Prashanth ◽  
Nitendra Palankar ◽  
A. U. Ravi Shankar
Keyword(s):  
Asphalt Pavement ◽  
Reclaimed Asphalt Pavement ◽  
Asphalt Mixes ◽  
Reclaimed Asphalt ◽  
Mastic Asphalt ◽  
Stone Mastic Asphalt

scholarly journals Rutting and moisture-induced damage potential of foamed warm mix asphalt (WMA) containing RAP

2021 ◽  
Vol 6 (3) ◽  
Author(s):  
Mohammad Ashiqur Rahman ◽  
Rouzbeh Ghabchi ◽  
Musharraf Zaman ◽  
Syed Ashik Ali
Keyword(s):  
Asphalt Pavement ◽  
Warm Mix Asphalt ◽  
Environmental Benefits ◽  
Reclaimed Asphalt Pavement ◽  
Chemical Additives ◽  
Flow Number ◽  
Damage Potential ◽  
Asphalt Mixes ◽  
Reclaimed Asphalt ◽  
Wheel Tracking

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.

scholarly journals A Method to Quantify Reclaimed Asphalt Pavement Binder Availability (Effective RAP Binder) in Recycled Asphalt Mixes

2019 ◽  
Vol 2673 (1) ◽  
pp. 205-216 ◽  
Author(s):  
Fawaz Kaseer ◽  
Edith Arámbula-Mercado ◽  
Amy Epps Martin
Keyword(s):  
Asphalt Pavement ◽  
Economic Benefits ◽  
Binder Content ◽  
Mix Design ◽  
Void Content ◽  
Reclaimed Asphalt Pavement ◽  
Asphalt Mixes ◽  
Reclaimed Asphalt ◽  
State Highway ◽  
Asphalt Mix

State highway agencies recognize the environmental and economic benefits of utilizing reclaimed asphalt pavement (RAP) in asphalt mixes. Currently, most agencies assume all of the RAP binder content is available for mix design purposes. However, the percentage of available or effective RAP binder in the asphalt mix is usually less than 100% and not quantified, which could yield dry asphalt mix with a high air void content, potentially leading to premature distress. The term available or effective RAP binder refers to the binder that is released from the RAP, becomes fluid, and blends with virgin binder under typical mixing temperatures. This study proposes a method to estimate the RAP binder availability factor (BAF) which can be used to adjust the virgin binder content in RAP mixes to ensure that the mix design optimum binder content is achieved. In this method, asphalt mixes were prepared so that, after mixing and conditioning, the RAP material can be separated from the virgin aggregate, which allows for a thorough evaluation of the extent of RAP binder availability in the asphalt mix. This method was verified in a preliminary experiment and then used to estimate the BAF of RAP from different sources, and a correlation between RAP BAF and the high temperature performance grade (PG) of each RAP source was established. Finally, factors affecting the RAP BAF were also evaluated such as mixing temperature, conditioning period, the use of recycling agents (or rejuvenators), and the method of adding the recycling agent to the mix.

scholarly journals Mechanical performance assessment of half warm recycled asphalt mixes containing up to 100 % RAP

2017 ◽  
Vol 7 (080) ◽  
pp. 129 ◽  
Author(s):  
J. M. Lizárraga ◽  
A. Jiménez del Barco-Carrión ◽  
A. Ramírez ◽  
P. Díaz ◽  
F. Moreno-Navarro ◽  
...  
Keyword(s):  
Hot Mix Asphalt ◽  
Mechanical Performance ◽  
Asphalt Pavement ◽  
Reclaimed Asphalt Pavement ◽  
Recycled Asphalt ◽  
Stiffness Modulus ◽  
Asphalt Mixes ◽  
Reclaimed Asphalt ◽  
Second Stage ◽  
Asphalt Content

The use of Half Warm Mixes with high Reclaimed Asphalt content (HWMRA) has the potential to generate significant environmental advantages such as the reduction in consumption of natural resources and the emission of gases into the atmosphere. This paper therefore focuses on demonstrating the viability of using these types of mixes in wearing courses. For this purpose, an HWMRA with 70 % and 100 % Reclaimed Asphalt Pavement (RAP) and emulsion were designed in the laboratory. The performance of the mixes was then assessed and compared with that of conventional Hot Mix Asphalt. In a second stage, the mixes were manufactured in-plant, and laid and compacted in an Accelerated Pavement Test track. The cores were then extracted and tested for stiffness modulus and resistance to fatigue. The results from the tests conducted with both the laboratory specimens and the cores showed that the performance of HWMRA is comparable to that of HMA. These findings encourage greater confidence in promoting the use of these types of sustainable asphalt mixes.

scholarly journals The Design and Material Characterization of Reclaimed Asphalt Pavement Enriched Concrete for Construction Purposes

Materials ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 4986
Author(s):  
Jaroslav Pokorný ◽  
Radek Ševčík ◽  
Jiří Šál
Keyword(s):  
Construction Industry ◽  
Mechanical Performance ◽  
Asphalt Pavement ◽  
Analytical Techniques ◽  
Reclaimed Asphalt Pavement ◽  
Waste Products ◽  
Asphalt Mixes ◽  
Reclaimed Asphalt ◽  
Natural Aggregate ◽  
Innovative Products

Reclaimed asphalt pavement (RAP) is a valuable commodity originating during processes of road/highways rehabilitations, resurfacing in the cases of the revelation of underneath-placed layers. Removed material can be successfully recycled and utilized as a supplementing material for new hot asphalt mixes. However, its dosages are limited because of variations in properties of aged bitumen compared to fresh material and, thus, a significant amount of waste material is remaining as waste products. Nonetheless, this commodity may find usage in the construction industry that suffers from a shortage of high-quality and easily available aggregates. This work aimed to investigate the optimal substitution of mined natural aggregate with commonly available RAP in order to produce composites with the comparable mechanical performance of reference ordinary Portland concrete. The aggregate substitutions up to 100% with RAP have been studied with a combination of mechanical and analytical techniques. Obtained experimental data showed changes in the porous structure, mineralogy, and in the amount of formed cement-related hydration products that influenced the mechanical performance of produced composites. Composite with 10% of natural aggregate substitution with RAP has shown the strength class C16/20 after 28 days of water curing, according to the EN 206-1. Such innovative products could be utilized in the construction industry. The usage of waste RAP could contribute to preservation of our environment for future generations.

scholarly journals Utilizing Reclaimed Asphalt Pavement (RAP) Materials in New Pavements - A Review

2015 ◽  
Vol 12 (1) ◽  
Keyword(s):  
Natural Resources ◽  
Asphalt Pavement ◽  
Fatigue Cracks ◽  
Permanent Deformation ◽  
Public Works ◽  
Main Concern ◽  
Reclaimed Asphalt Pavement ◽  
Asphalt Mixes ◽  
Reclaimed Asphalt ◽  
Thermal Cracks

Recently, prices of asphalt pavement materials have been increasing tremendously, which led to attempts to find alternative cheap materials. In addition, more concerns are directed to reserving natural resources and reducing environmental impacts of using virgin asphalt binders, thus more attention is focused on the use of recycled materials in pavement designs. Transportation agencies worldwide are incorporating reclaimed asphalt pavement (RAP) materials in new pavement designs. RAP was used for the first time in 1973, however, with low percentages due to the lack of understanding of its effect on the performance of asphalt mixes. Currently, higher percentages (e.g. >50%) are being utilized to reduce costs and natural resources and make use of demolished old asphalt pavements. The main concern of combining RAP in new asphalt mixes is how it will affect the resistance of these mixes to permanent deformation (rutting), fatigue cracks, and thermal cracks, which are the main distresses that affect the performance of asphalt mixes. Many studies were conducted to evaluate the effects of RAP on asphalt mixes, and all results showed that RAP increased the stiffness of asphalt mixes, thus improving rutting resistance at high temperature. On the other hand, results were in conflict with regard to fatigue and thermal cracking. Recently, the Department of Public Works and Services at Ras Al Khaimah, UAE started adopting RAP mixes in ongoing projects (e.g. Kadra-Shawka Road) with no clear guidelines, in hope of reducing costs and that these roads would have better performance. To address the concerns of the effects of RAP and to determine the correct RAP percentage for projects in Ras Al Khaimah, this study was initiated and as a first stage a literature review was conducted and presented in this article.

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