Abstract. In recent years, the use of foamed bitumen technology along with Reclaimed Asphalt Pavement is gaining popularity across the world. The mechanical response of foamed bitumen mixtures containing reclaimed asphalt pavement is significantly influenced by constituent material properties and aggregate gradation. This article presents results from a study where foamed bitumen mixtures conforming to Indian specifications were evaluated. For this purpose, foamed bitumen mixtures using a different percentage of reclaimed asphalt pavement and bitumens were prepared. Initially, the foaming characteristics of virgin bitumens were evaluated to optimize for optimum water content and foaming temperature. In the second stage, mixture design was conducted to optimize for foamed bitumen content in foamed bitumen mixtures containing a different percentage of reclaimed asphalt pavement. Finally, these foamed bitumen mixtures were evaluated for their mechanical properties. The results from this laboratory study indicated properties of foamed bitumen and foamed mixtures are significantly influenced by properties of bitumen, the quantity of bitumen, and reclaimed asphalt pavement. Among the different mixtures, a mixture containing 50% reclaimed asphalt pavement exhibited best results in resilient modulus and resistance to moisture damage tests. A mixture containing 80% reclaimed asphalt pavement also shows acceptable strength and resistance to water susceptibility. Thus, it is possible to design high-quality bituminous mixes using higher reclaimed asphalt pavement percentages, which meet the required volumetric and desired performance criteria.
Foamed bitumen technology is gaining acceptance across the world as an approach towards sustainable road construction. This technology offers advantages in terms of reduced energy consumption, materials recycling and reduced bitumen requirement. The properties of foamed bitumen mixtures depend on various factors, including the properties of the constituent materials and production conditions. This paper concentrates on the influence of the properties of the binder on the foaming characteristics of bitumen and the properties of foamed bitumen mixtures. Initially, four binders of different grades were evaluated for physical properties and foaming characteristics. The optimum foam content was then used to prepare foamed bituminous mixtures containing recycled asphalt pavement. These mixtures were evaluated for their mechanical properties, including indirect tensile strength, retained tensile strength and resilient modulus. The results from this laboratory study indicate that the properties of foamed bitumen and foamed mixtures are significantly influenced by the physical properties of the binder used, the quantity of binder and the recycled asphalt content. For a particular binder content in the mixture, use of a higher viscosity grade binder resulted in higher indirect tensile strength. A higher recycled asphalt pavement content in the mixture also resulted in higher indirect tensile strength. For all binder grades, a larger resilient modulus was observed for binder content the range of 2·3–2·5%.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.