Fatigue resistance investigation of warm-mix recycled asphalt binder, mastic, and fine aggregate matrix

2017 ◽  
Vol 41 (2) ◽  
pp. 400-411 ◽  
Author(s):  
Q. Li ◽  
X. Chen ◽  
G. Li ◽  
S. Zhang
Keyword(s):  
Fatigue Resistance ◽  
Asphalt Binder ◽  
Fine Aggregate ◽  
Recycled Asphalt ◽  
Fine Aggregate Matrix

Experimental Testing and Analysis Procedure to Determine the Apparent Film Thickness of Asphalt Binder in Fine Aggregate Matrix Mixtures

2021 ◽  
Vol 2675 (7) ◽  
pp. 166-179
Author(s):  
Lucas Henrique Vieira ◽  
Thiago Delgado de Souza ◽  
Alexis Jair Enríquez-León ◽  
Francisco Thiago Sacramento Aragão ◽  
Otávio da Fonseca Martins Gomes ◽  
...  
Keyword(s):  
Film Thickness ◽  
Asphalt Concrete ◽  
Experimental Testing ◽  
Asphalt Binder ◽  
Analysis Procedure ◽  
Fine Aggregate ◽  
Concrete Mixtures ◽  
Proper Design ◽  
Fine Aggregate Matrix ◽  
Imagej Software

The fine aggregate matrix (FAM) is an important constituent of an asphalt concrete mixture; the FAM is where some key damage phenomena such as cracking start and propagate. The proper design and fabrication of isolated FAM testing samples that are representative of the material existing within asphalt concrete mixtures requires the objective determination of key characteristics such as the apparent film thickness (FT) of the asphalt binder and the specific surface area of the aggregates. These relevant parameters facilitate the estimation of the binder content. This study presents an experimental testing and analysis protocol to determine the apparent FT that covers particles of fine aggregate in FAM mixtures. The method is based on tests using a scanning electron microscope and a digital image analysis procedure using the open-source Fiji/ImageJ software. The results indicated that apparent FT ranged between 0.5 µm and 30 µm. An additional validation effort was pursued and demonstrated the applicability of the proposed methodology, which can provide meaningful information to improve volumetric-based FAM mix design methods and generate materials that are more representative of those existing in the asphalt concrete mixtures.

scholarly journals Evaluating the Effects of High RAP Content and Rejuvenating Agents on Fatigue Performance of Fine Aggregate Matrix through DMA Flexural Bending Test

Materials ◽  
2019 ◽  
Vol 12 (9) ◽  
pp. 1508 ◽  
Author(s):  
Chenchen Zhang ◽  
Qi Ren ◽  
Zhendong Qian ◽  
Xudong Wang
Keyword(s):  
Fatigue Life ◽  
Phase Angle ◽  
Fatigue Resistance ◽  
Prediction Models ◽  
Asphalt Mixtures ◽  
Traffic Load ◽  
Bending Test ◽  
Fine Aggregate ◽  
Test Results ◽  
Fine Aggregate Matrix

High percentage reclaimed asphalt pavement (RAP) is prevailing in pavement engineering for its advantages in sustainability and environmental friendliness, however, its fatigue resistance remains a major concern. Fine aggregate matrix (FAM) is a crucial part in the fatigue resistance of asphalt mixtures with high RAP content. Hence, the linear amplitude sweep (LAS) test of FAM has been developed to study the fatigue resistance of asphalt mixtures. However, the torsional loading mode of the LAS test with a dynamic shear rheometer (DSR) is a limitation to simulate traffic load. In this paper, an alternative LAS test for FAM with high RAP content was proposed. Beam FAM specimens were tested using a dual-cantilever flexural loading fixture in a dynamic mechanical analyzer (DMA). To investigate the influence of RAP content and the rejuvenating agent (RA), four kinds of FAM mixes were tested with this method to study their fatigue resistance. The test results suggested that the repeatability of this alternative approach was reliable. A fatigue failure criterion based on maximum C × N was defined. Then, fatigue life prediction models based on viscoelastic continuum damage (VECD) analysis were established according to the LAS test results and validated by a strain-controlled time sweep (TS) test. It turned out that as RAP content increased, the modulus of FAM would be significantly raised, accompanied with a drop in the phase angle. The fatigue life of FAM would be greatly shortened when the RAP binder replacement rate reached 50%. Adding RA could considerably improve the dynamic properties of FAM mixes with high RAP content, resulting in a decrease in modulus, increase in phase angle and elongating fatigue life, but could not recover to the level of virgin binder.

scholarly journals Effect of Blending Degree between Virgin and Aged Binder on Pavement Performance of Recycled Asphalt Mixture with High RAP Content

2019 ◽  
Vol 2019 ◽  
pp. 1-15 ◽  
Author(s):  
Ying Xu ◽  
Zhijing Chou ◽  
Yunze Li ◽  
Jie Ji ◽  
Shi-fa Xu
Keyword(s):  
Low Temperature ◽  
Fatigue Resistance ◽  
Asphalt Binder ◽  
Asphalt Mixture ◽  
Pavement Performance ◽  
Design Stage ◽  
Recycled Asphalt ◽  
Moisture Stability ◽  
Aged Binder ◽  
Resistance Performance

In this study, the influence of the blending degree between virgin and aged binder on the pavement performance of hot-mix recycled asphalt mixture (HMRAM) with high RAP content is analyzed. The aggregate gradation of AC-16 was selected. The RAP contents were 30, 40, and 50%. HMRAMs with different degrees of blending (DOBs) were prepared by changing the mixing temperature (150, 165, and 180°C) without the occurrence of excessive aging for asphalt binders. An improved Hirsch dynamic modulus prediction model was then used to quantitatively characterize the DOB of HMRAM. Finally, the high-temperature, low-temperature, moisture stability, and fatigue resistance performance of HMRAM were tested and the effect of the DOB between the virgin and aged asphalt binder on the pavement performance was analyzed. The results showed that the DOB between the virgin and aged asphalt binder cannot reach 100% at the three mixing temperatures for HMRAM with 30, 40, and 50% RAP contents, which is inconsistent with the assumption of complete blending in China’s specification. The dynamic stability of the mixture gradually decreases with the increased DOB for HMRAM with a high RAP content, while the moisture stability, low-temperature, and fatigue resistance performance are continuously improved. This means that with the increase in DOB in the stage of open to traffic, meeting high-temperature performance criteria at the design stage may become unsatisfactory for HMRAM. The moisture stability, low-temperature performance, and fatigue resistance performances of HMRAM measured at the design stage were reasonable and conservative. The change in DOB significantly affects the content and properties of total free binder in HMRAM, affecting pavement performance. The content and physical properties of the RAP aggregate also have a significant impact on pavement performance.

scholarly journals Fatigue Resistance and Cracking Mechanism of Semi-Flexible Pavement Mixture

Materials ◽  
2021 ◽  
Vol 14 (18) ◽  
pp. 5277
Author(s):  
Shiqi Wang ◽  
Huanyun Zhou ◽  
Xianhua Chen ◽  
Minghui Gong ◽  
Jinxiang Hong ◽  
...  
Keyword(s):  
Low Temperature ◽  
Fatigue Resistance ◽  
Stress Ratio ◽  
Asphalt Binder ◽  
Asphalt Mixture ◽  
Fatigue Cracking ◽  
Flexible Pavement ◽  
The Poor ◽  
Grouting Material ◽  
Cracking Mechanism

Semi-flexible pavement (SFP) is widely used in recent years because of its good rutting resistance, but it is easy to crack under traffic loads. A large number of studies are aimed at improving its crack resistance. However, the understanding of its fatigue resistance and fatigue-cracking mechanism is limited. Therefore, the semi-circular bending (SCB) fatigue test is used to evaluate the fatigue resistance of the SFP mixture. SCB fatigue tests under different temperature values and stress ratio were used to characterize the fatigue life of the SFP mixture, and its laboratory fatigue prediction model was established. The distribution of various phases of the SFP mixture in the fracture surface was analyzed by digital image processing technology, and its fatigue cracking mechanism was analyzed. The results show that the SFP mixture has better fatigue resistance under low temperature and low stress ratio, while its fatigue resistance under other environmental and load conditions is worse than that of asphalt mixture. The main reason for the poor fatigue resistance of the SFP mixture is the poor deformation capacity and low strength of grouting materials. Furthermore, the performance difference between grouting material and the asphalt binder is large, which leads to the difference of fatigue cracking mechanism of the SFP mixture under different conditions. Under the fatigue load, the weak position of the SFP mixture at a low temperature is asphalt binder and its interface with other materials, while at medium and high temperatures, the weak position of the SFP mixture is inside the grouting material. The research provides a basis for the calculation of the service life of the SFP structure, provides a reference for the improvement direction of the SFP mixture composition and internal structure.

Review From Multiple Perspectives for the State of the Practice on the Use of Recycled Asphalt Materials and Recycling Agents in Asphalt Concrete Surface Mixtures

2021 ◽  
pp. 036119812110611
Author(s):  
Jhony Habbouche ◽  
Ilker Boz ◽  
Benjamin Shane Underwood ◽  
Cassie Castorena ◽  
Saqib Gulzar ◽  
...  
Keyword(s):  
Quality Control ◽  
Asphalt Concrete ◽  
Asphalt Binder ◽  
Concrete Surface ◽  
Lessons Learned ◽  
Multiple Perspectives ◽  
Recycled Asphalt ◽  
Recycled Materials ◽  
Continuous Quality ◽  
Virginia Department

The objective of this paper is to provide information from multiple perspectives on the current state of the practice with regard to using recycled materials and recycling agents (RAs) in asphalt concrete mixtures. This information was collected through a survey of U.S. transportation agencies and RA suppliers combined with a search of RA-related specifications and pilot projects previously constructed. Moreover, a case study describing the Virginia Department of Transportation’s experience with RAs provides a tangible example of how at least one agency is approaching the potential implementation of these technologies. This practice review was achieved by documenting the experience, lessons learned, and best practices of multiple asphalt experienced contractors and asphalt binder suppliers in the Virginia area. This paper follows a similar survey conducted in 2014 as part of NCHRP 09-58 and provides a second look at the use of RAs across North America. Not all state departments of transportation have experience with using RAs. Factors preventing the use of RAs included specification limitations, lack of expertise in processing recycled materials, supporting data, and negative prior experiences. Developing a performance-based testing framework is mandatory for the successful use of RAs. In general, good and frequent communication with the RA supplier is critical and necessary during the planning stages, the production of mixtures, and the continuous quality control by the supplier to resolve issues when they arise. Finally, a strong quality control and quality assurance-testing program should be implemented to ensure that materials meet the properties needed to produce a good-performing mixture.

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