Applications of reclaimed asphalt pavement in India – A review

Rheological Evaluation of Softened Binders Blended with Aged Asphalt Selected with a High-Temperature Mixing Chart

“…The pavement industry is a vital sector that can actively serve a country’s economy by contributing to the GDP [ 1 ], although it has grown tremendously, leading to shortages and higher prices for aggregates and binder. [ 2 ].…”

“…Consequently, if 100% of the RAP is used, the need for virgin materials would be reduced, thereby inducing sustainability in pavements [ 11 ]; hence, RAP has been widely used because it helps to reduce costs in the construction of flexible pavements, conserves natural resources [ 4 , 8 , 17 , 18 , 19 , 20 ], requires low amounts of energy and fuel [ 1 , 9 ], eliminates solid waste, and reduces the carbon footprint [ 3 , 10 , 11 , 12 ]. In this sense, according to Debbarma and G. D. Ransinchung [ 21 ], there were reductions of 67% and 18% in cost and gas emissions, respectively, when RAP was used in asphalt mixtures, while CO 2 emissions were reduced by 2%.…”

“…Therefore, there are negative perceptions and practical problems limiting the use of RAP: (a) the quality of the RAP aggregates; (b) the technology of the production plant; (c) the mix design methodology; (d) the performance of the final mix containing RAP [ 1 , 5 ]; (e) the normative restrictions [ 4 ]. It is now known that the interfacial binding energy between the asphalt-coated RAP aggregates causes a reduction in the resistance of the RAP in the mixtures [ 1 , 11 ]. In addition, if the recycled pavement is incorrectly designed, the expected service life of the pavement will be reduced [ 10 ].…”

“…In the same way, due to the inconveniences explained by Devulapalli, Kothandaraman and Sarang [ 8 ], as well as Li, et al [ 24 ], as RAP is exposed to weathering factors such as temperature, ultraviolet light, rain, and oxygen during its useful life, the RAP binder (AC-RAP) undergoes aging, causing it to lose its rheological properties, having high viscosity (stiffness) and poor elasticity, which stiffens the asphalt mix. [ 1 , 2 , 10 , 18 , 19 , 25 ]. Rheology studies relate to the internal responses of viscoelastic materials such as asphalts when they are deformed due to applied stresses.…”

“…A literature review confirmed that the stiffness of RAP blends is higher than that of virgin blends [ 6 , 33 ]. Low RAP levels (<50%) do not greatly affect the resistance, porosity, water absorption, reduced rutting, increased tensile strength, or modulus [ 1 , 2 , 3 , 7 , 9 , 11 , 15 ]. Additionally, as the RAP content increases, the cracking deterioration [ 5 , 8 , 12 , 34 , 35 , 36 ] and susceptibility to moisture increase [ 10 ], while the dynamic modulus and tensile strength decrease [ 15 , 17 ].…”