Evaluation of mix design volumetrics and cracking potential of foamed Warm Mix Asphalt (WMA) containing Reclaimed Asphalt Pavement (RAP)

2021 ◽  
pp. 1-13
Author(s):  
Mohammad Ashiqur Rahman ◽  
Musharraf Zaman ◽  
Syed Ashik Ali ◽  
Rouzbeh Ghabchi ◽  
Sagar Ghos
Keyword(s):  
Asphalt Pavement ◽  
Warm Mix Asphalt ◽  
Mix Design ◽  
Reclaimed Asphalt Pavement ◽  
Reclaimed Asphalt ◽  
Cracking Potential

scholarly journals Recent Development in High-Content Reclaimed Asphalt Use

2020 ◽  
Vol 198 ◽  
pp. 01024
Author(s):  
Jiang Chaoyang
Keyword(s):  
Positive Result ◽  
Recent Progress ◽  
Asphalt Pavement ◽  
Economic Value ◽  
Warm Mix Asphalt ◽  
Mix Design ◽  
Reclaimed Asphalt Pavement ◽  
Reclaimed Asphalt ◽  
Current Production ◽  
Production Technologies

In recent years, the use of recycled materials in construction and maintenance has increased significantly and been adopted as a common practice in the industrial field. Reclaimed asphalt pavement (RAP) is one of the most ideal materials that contain huge environmental and economic value. The present challenges faced with RAP is low utilization and degradation problems. Increasing the amount of RAP used in the mix design is considered an effective method to address these problems and can producing a three-fold benefit for the environment, economic, and landfill stress. The key point of increasing RAP use is usually reflected in the proper utilization of current production technologies, new mix design, and management. This paper summarizes the main limitation, distress, and present recent progress in high RAP use. The most common practice be utilized are the use of softer bitumen, softening additives and rejuvenators, while the application of warm mix asphalt technology also showed a positive result. The research results suggest that the utilization of those new practices could achieve better cracking resistance and improve the work-ability and rutting potential.

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 Evaluation of Gas Emissions, Energy Consumption and Production Costs of Warm Mix Asphalt (WMA) Involving Natural Zeolite and Reclaimed Asphalt Pavement (RAP)

2020 ◽  
Vol 12 (16) ◽  
pp. 6410
Author(s):  
Alejandra T. Calabi-Floody ◽  
Gonzalo A. Valdés-Vidal ◽  
Elsa Sanchez-Alonso ◽  
Luis A. Mardones-Parra
Keyword(s):  
Energy Consumption ◽  
Fuel Consumption ◽  
Natural Zeolite ◽  
Asphalt Pavement ◽  
Warm Mix Asphalt ◽  
Production Costs ◽  
Partial Replacement ◽  
Reclaimed Asphalt Pavement ◽  
Gas Emissions ◽  
Reclaimed Asphalt

Asphalt mixture is the most widely used material in road construction, and the industry is developing more sustainable technologies. Warm mix asphalt (WMA) is a promising alternative as it saves energy, reduces fuel consumption and generates fewer gas and fume emissions, while maintaining a similar performance to hot mix asphalt (HMA). This paper presents an evaluation of the gas emissions at laboratory scale, as well as the energy consumption and production costs, of five types of WMA with the addition of natural zeolite. The control mixture was a HMA manufactured at 155 °C. The mixtures evaluated were two WMA manufactured at 135 °C with 0.3% and 0.6% natural zeolite, and three WMA with partial replacement of raw materials by 10%, 20% and 30% of reclaimed asphalt pavement (RAP); these mixtures, called WMA–RAP, were manufactured at 125 °C, 135 °C and 145 °C, respectively. The results indicated that all the mixtures evaluated reduced CO and CO2 emissions by 2–6% and 17–37%, respectively. The energy consumption presented a 13% decrease. In the current situation, the production costs for WMA with 0.3 and 0.6% natural zeolite are slightly higher than the control mixture, because the saving achieved in fuel consumption is lower than the current cost of the additive. On the other hand, WMA manufactured with the addition of natural zeolite and RAP could produce cost savings of up to 25%, depending on the amounts of RAP and natural zeolite used.

High-Performance Thin-Lift Overlays with High Reclaimed Asphalt Pavement Content and Warm-Mix Asphalt Technology

2012 ◽  
Vol 2293 (1) ◽  
pp. 18-28 ◽  
Author(s):  
Walaa S. Mogawer ◽  
Alexander J. Austerman ◽  
Robert Kluttz ◽  
Michael Roussel
Keyword(s):  
High Performance ◽  
Asphalt Pavement ◽  
Warm Mix Asphalt ◽  
Asphalt Binders ◽  
Reclaimed Asphalt Pavement ◽  
Moisture Susceptibility ◽  
Reclaimed Asphalt ◽  
Pavement Preservation ◽  
Asphalt Overlay ◽  
Structural Capacity

A high-performance thin asphalt overlay (HPThinOL) is specified as having a thickness of 1 in. or less and is used in applications requiring high levels of rutting and fatigue resistance. HPThinOLs are used as a pavement preservation strategy and are placed on pavements that have remaining structural capacity that is expected to outlive that strategy. Current specifications for HPThinOLs generally call for a polymer-modified asphalt (PMA). However, PMA binders are more expensive than unmodified asphalt binders. This expense, coupled with the higher binder content requirement generally associated with HPThinOL, could lead to an initial higher cost in relation to other pavement preservation strategies. Although the higher initial cost can be offset by incorporating high amounts of reclaimed asphalt pavement (RAP), the use of high amounts of RAP in PMA mixtures might adversely affect the mixture performance (stiffness, cracking, or workability). Warm-mix asphalt (WMA) technology may improve the workability of HPThinOL that incorporates high RAP content and PMA binders. This study evaluated the effect of PMA binders, high RAP content, and WMA technology on the stiffness, resistance to reflective cracking, moisture susceptibility, and workability of HPThinOL mixtures. PMA binders and high RAP content increased the stiffness of HPThinOL significantly; however, the use of WMA technology lowered mixture stiffness and improved workability. PMA may improve the cracking resistance, moisture susceptibility, and rutting resistance of high-RAP HPThinOL mixtures, depending on whether a WMA technology is used.

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.

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