Evaluation of optimum mixing conditions for rubberized asphalt mixture containing reclaimed asphalt pavement

2020 ◽  
Vol 234 ◽  
pp. 117426 ◽  
Author(s):  
Junqing Zhu ◽  
Tao Ma ◽  
Zhen Dong
2019 ◽  
Vol 2 (2) ◽  
pp. 149-157
Author(s):  
Hendra Arianto ◽  
Sofyan M. Saleh ◽  
Renni Anggraini

Reuse of reclaimed asphalt pavement material (RAP) is an alternative which applicated for potential enough on the roughness of the road. RAP material can be reused by adding the asphalt and the new aggregate according of the mixture composition so that it is expected will be obtained the quality as planned. One of the efforts made in improving the quality of asphalt mixture RAP material is using a modified asphalt with additional material, such as styrofoam. The use of styrofoam into the asphalt is expected to improve the technical properties of a mixture. The purpose of this research is to know the comparative characteristics of hot mix asphalt (asphalt concrete) type AC-WC that uses RAP material with additional asphalt pen. 60/70 and asphalt pen. 60/70 substitution in the styrofoam by 8%, 10% and 12% against the weight of asphalt based on levels of asphalt left on the material. The initial stages of this study is to conduct an examination of the physical properties of RAP material, then manufacturing a specimen with variations of the addition of asphalt and aggregate new levels based on the job mix diesign (JMD) Bina Marga Aceh (2013). Based on research results, parameter values marshall on all types of asphalt mixture with new aggregate as well as RAP materials and the use of 100% asphalt pen. 60/70 additional or different types of asphalt on OAC has fulfilled the technical specifications defined by the Bina Marga (2014). Best stability values obtained on asphalt mixture using RAP material with additional asphalt pen. 60/70 with 12% styrofoam substitution on OAC JMD Bina Marga Aceh, that amounted to 3,308.72 kg, the lowest value stability retrieved on asphalt mixture using a new aggregate based on the results of Department of Bina Marga Aceh on OAC i.e. of 983.94 kg.


Author(s):  
Baoshan Huang ◽  
Guoqiang Li ◽  
Dragan Vukosavljevic ◽  
Xiang Shu ◽  
Brian K. Egan

This paper presents a laboratory study in which the blending process of reclaimed asphalt pavement (RAP) with virgin mixture was analyzed through controlled experiments. One type of screened RAP was blended with virgin (new) coarse aggregate at different percentages. A blended mixture containing 20% of screened RAP was subjected to staged extraction and recovery. The result from this experiment indicated that only a small portion of aged asphalt in RAP actually participated in the remixing process; other portions formed a stiff coating around RAP aggregates, and RAP functionally acted as “composite black rock.” The resulting composite layered structure was desirable to improve the performance of the hot-mix asphalt mixture.


2012 ◽  
Vol 446-449 ◽  
pp. 2412-2417
Author(s):  
Li Ying Yang ◽  
Yi Qiu Tan ◽  
Hao Liu ◽  
En Guang Li

Reclaimed asphalt pavement (RAP) develops rapidly throughout the world. Hot recycling is one way to make effective use of the waste, but the percentage of RAP in hot recycling is no more than 30%. By way of warm asphalt technology, the percentage of RAP can increase greatly. In this paper, warm recycling is researched. The RAP and the virgin materials including aggregates and asphalt are tested and analyzed. Then, two warm recycling mixtures with different amount of RAP are designed and their properties are investigated. As a comparison, the performances of hot recycling are also tested. At last, the performances of warm recycling and hot recycling are compared and discussed. After the laboratory research, the warm recycling made its debut in Beijing and it exhibit very well, which testifies that warm recycling owns good properties. Warm recycling can make use of pavement waste, and it can decrease the emission and energy consumption. Warm mix is environment-friendly and it is promising in the near future.


Author(s):  
Jiantao Wu ◽  
Quan Liu ◽  
Yu Wang ◽  
Jun Chen ◽  
Dawei Wang ◽  
...  

Laboratory-produced reclaimed asphalt pavement (RAP) material, new aggregate, and tinted new binder were mixed (RAP proportion: 40%) with 12 different combinations of mixing temperatures and times, based on which circular specimens of various thicknesses were fabricated and then subjected to multi-direction indirect tensile stiffness modulus (ITSM) testing and color image analysis. Statistical calculations including average value, coefficient of variation, standard deviation, and range were carried out to investigate the effects of different mixing conditions on the homogeneity of asphalt mixtures containing RAP. The results show that the deterioration of homogeneity of asphalt mixtures containing RAP was mainly caused by the asynchronous breaking of clusters. The mixing temperature was decisive in determining the resistance of clusters to breaking, and for mixing conditions chosen in this study, the resistance increases with the increase of mixing temperature. Short mixing time might lead to a phenomenon of “momentary homogeneity,” in which clusters were not broken and the blending degree between aged and new binder was low.


Materials ◽  
2020 ◽  
Vol 13 (16) ◽  
pp. 3621
Author(s):  
Xiang Ma ◽  
Zhen Leng ◽  
Lili Wang ◽  
Peisheng Zhou

The compactability of an asphalt mixture is related to the heating temperature of the materials, but the heating temperature of reclaimed asphalt pavement (RAP) is limited by the production process of hot-in-plant recycled mixtures. To choose a reasonable heating temperature for RAP according to the compactability, the compaction energy ratio (CER) obtained from the Superpave gyratory compactor compaction curve was developed. The CERs of fourteen kinds of asphalt mixtures made with different RAPs were compared, all of which were different in type, content, and heating temperature. The results indicated that CER is an effective energy index to evaluate the workability of a bituminous mixture, and it considers both the accumulated energy after each gyration and the number of gyrations. It was also found that increasing the heating temperature of the RAP cannot always improve the workability of the recycled mixture, because the higher heating temperature caused more hard-aged bitumen to be blended with soft virgin bitumen during the mixing process. At the same RAP heating temperature, increasing the RAP content made it more difficult to compact the mixture, especially for RAPs with styrene–butadiene–styrene (SBS) modified bitumen, and the recycled mixtures with SBS-modified bitumen were more difficult to compact than those with nonmodified bitumen.


Materials ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4137
Author(s):  
Quan Liu ◽  
Markus Oeser

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.


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