Recycling of Waste Originating Form Flexible Pavements for Bound-Base Courses of Flexible Pavements

2020 ◽  
Vol 46 (3) ◽  
pp. 394-408
Author(s):  
Kumari Monu ◽  
G.D. Ransinchung R.N. ◽  
Surender Singh ◽  
Gaurav Singh Raghav

Reclaimed Asphalt pavement (RAP) is a C&D waste originating from the reclamation of asphalt pavement which has completed its service life. Using RAP would potentially reduce reliance on primary aggregates and lowers the environmental impact of construction. The present study is an attempt made to utilize RAP judiciously as a bound base course of the flexible pavement. Natural coarse aggregates were replaced by RAP in proportions of 50% & 100% with & without Warm Mix Asphalt (WMA), for production of bound-base course mixes. To ensure the long run performance, the aging condition was simulated in the laboratory and mechanical properties such as Marshall Stability, Tensile Strengths, Marshall Stability Retained, Indirect Tensile Ratio, rutting resistance, Fatigue life, and abrasion resistance were considered. With the incorporation of 50-100% coarse RAP, the Marshall Stability, rutting resistance and abrasion were found to be improved by 30-32%, 43-104% and 11-17% respectively. Similarly, total cost saving is about 15-35%, which is quite significant. However, the addition of WMA enhanced the cost by 3-4%, which is insignificant when combined with RAP, furthermore, the reductions in fume emission enhance the sustainability aspect of the technology.

During the maintenance or the construction of asphalt pavement the utilization of reclaimed asphalt pavement (RAP) can diminish the cost of the project, time consumption, conservation of natural resources and most importantly no harm to the environment. In this paper we are going to study the performance of pavement containing RAP (20%, 30%, 40% and 50% excluding the RAP aggregates of size 20 mm), anti-stripping agent Zycotherm, 1% of virgin bitumen contain are replaced by bitumen attached on RAP aggregates after the screening process. Tests performed for conventional and modified pavement sample are Marshall Stability and flow. Test for virgin aggregates and RAP aggregates are impact test, crushing test, shape test, specific gravity and bitumen extraction test. Test for virgin bitumen and modified bitumen are softening and penetration test.


Author(s):  
Anusha T M ◽  
◽  
Sharath Kumar M D ◽  
Dr. H S Jagadeesh ◽  
◽  
...  

SMA is a gap graded mix composed of a high concentration of coarse aggregate that is held together in a thick asphalt film by a matrix of mineral filler and stabilizers. Since natural aggregates have become expensive, hence Reclaimed Asphalt Pavement (RAP) can be reused in pavement construction to reduce the environmental hazardous due to disposal problems. Since the RAP contains used aggregates, it is highly prone to fatigue, thermal and reflective cracking effect. Rheological and chemical properties of aged bitumen in RAP can be enhanced by use of untreated waste oils such as waste engine oil as rejuvenators. This research presents a study on fatigue performance of SMA mix with Reclaimed Asphalt Pavement (RAP) materials with and without rejuvenators and results were compared with conventional SMA mix. The materials used were first characterized by common laboratory tests. Then the three SMA mixes are tested using several laboratory test procedures: Marshall Stability, indirect tensile strength, moisture susceptibility, and indirect tension fatigue test. The optimum proportions of the of the mixes with highest stability are selected from the Marshall stability test. The indirect tensile strength test results show that the SMA mix replaced with RAP without rejuvenators showed higher tensile strength ratio and resistance to moisture damage when compared to conventional mix and optimum RAP replacement mix with rejuvenators. The fatigue test was conducted for the three optimum mixes at different temperature and stresses. The fatigue test results showed that at lower temperature and stresses, the RAP replaced SMA without rejuvenator offered better fatigue resistance than those with rejuvenator and conventional SMA mix. At higher temperatures, the RAP replaced SMA mix with rejuvenator offered similar fatigue lifecycle as conventional mix. However, at high stresses, conventional SMA mix offered better fatigue lifecycle. Increase in failure stresses resulted in decrease of number of fatigue cycles and increased in initial tensile strain of the mix. Thus, with the use of RAP substantial decrease in cost can be achieved without compromising the fatigue characteristic of the SMA mix.


Materials ◽  
2021 ◽  
Vol 14 (22) ◽  
pp. 7060
Author(s):  
Mohammad Alharthai ◽  
Qing Lu ◽  
Ahmed Elnihum ◽  
Asad Elmagarhe

This study investigates the substitution of conventional aggregate with a Florida washed shell in open-graded asphalt mixtures and evaluates the optimal substitution percentage in aggregate gradations of various nominal maximum aggregate sizes (NMASs) (i.e., 4.75, 9.5, and 12.5 mm). Laboratory experiments were performed on open-graded asphalt mixture specimens with the coarse aggregate of sizes between 2.36 and 12.5 mm being replaced by the Florida washed shell at various percentages (0, 15, 30, 45, and 100%). Specimen properties relevant to the performance of open-graded asphalt mixtures in the field were tested, evaluated, and compared. Specifically, a Marshall stability test, Cantabro test, indirect tensile strength test, air void content test, and permeability test were conducted to evaluate the strength, resistance to raveling, cracking resistance, void content, and permeability of open-graded asphalt mixtures. The results show that there is no significant difference in the Marshall stability and indirect tensile strength when the coarse aggregates are replaced with Florida washed shell. This study also found that the optimum percentages of Florida washed shell in open-graded asphalt mixture were 15, 30, and 45% for 12.5, 9.5, and 4.75 mm NMAS gradations, respectively.


2018 ◽  
Vol 162 ◽  
pp. 01037 ◽  
Author(s):  
Karim Al helo ◽  
Zaynab Qasim ◽  
Ahmed Majeed

This paper presented the effect of addition of Reclaimed Asphalt Pavement (RAP) on performance of mixture with (20%, 30%, 40% and 50%) RAP as proportion of asphalt mix. To compare with virgin mixture marshall flow and stability test was used to evaluated durability performance with (0,1,3, and 7) days immersion and Wheel Truck test was used to evaluated the resist to rutting. The best gradation and optimum asphalt content was selected according to Superpave system. Superpave Gyratory Compactor (SGC) was used to compact mixture with 100-mm diameter. The test results indicated that addition of RAP to mixes showed significant increase on resistance of Durability and Rutting.


Author(s):  
Emre Akmaz ◽  
Saad Ullah ◽  
Burak F. Tanyu ◽  
Erol F. Guler

Reclaimed asphalt pavement (RAP) is already being recycled as a construction and building material. One of the commonly considered applications is to create an unbound aggregate from this material. However, since the particles of RAP have binder coatings, traditional quality control procedures applied during construction such as use of a nuclear density gauge does not provide accurate results. Therefore there is a need to find another method that can be applied during construction to confirm that the placement in the field meets the design criteria. For this reason, in this study, the suitability of using light weight deflectometer (LWD) has been investigated. The presented methodology outlines how to implement the use of LWD to create a target modulus in the laboratory as part of design criteria and compare with the field measurements. In the field, depending on the thickness of the constructed aggregate layer, the LWD measurements may be influenced by more than just the layer of interest. The presented methodology also provides a solution for such multilayer conditions. Although the study primarily focuses on using RAP as the investigated material, the methodology developed in this study can be applied to any type of unbound aggregate as demonstrated in this study.


2011 ◽  
Vol 2011 ◽  
pp. 1-7 ◽  
Author(s):  
Kevin C. Foye

The use of Reclaimed Asphalt Pavement (RAP) in lieu of virgin crushed stone aggregate is becoming a widely accepted practice for a number of construction applications, particularly pavement base courses. A number of laboratory RAP studies have considered the mechanical properties of RAP bases in order to support pavement designs incorporating RAP. These studies have revealed a number of interesting relationships between RAP moisture content, compaction, and stiffness. This paper discusses the experiences of a design-build contractor integrating a geosynthetic ground improvement program with a RAP base during the reconstruction of a 1.95 ha asphalt parking lot. Field observations of base course construction with RAP explore some of the implications of laboratory findings. A number of interesting observations on the technical, construction, and economic issues resulting from the project challenges and the use of RAP are presented.


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