## 1 Introduction  
Bitumen is considered to be an essential component of roadways and its demand is increasing with each passing day. According to the Asphalt Institute, 87 million tons of bitumen are produced per year around the globe [1]. A major chunk of this production, approximately 85% of the bitumen, is used in the paving industry. With the increase in traffic loads, the need for progress in pavement technology is also increasing. The early failure of pavement calls for its reconstruction, which results in an increased demand for bitumen. In order to conserve the resources, it is necessary to ensure the construction of sustainable pavements. In Pakistan, two commonly observed highway failures are rutting and moisture damage. The poor mix properties of asphalt and the high temperature greatly contribute to these failures. The temperature cannot be controlled; however, the properties of asphalt can be improved for better temperature resistance. For over 50 years, researchers have been using various asphalt modifiers to achieve the desired material properties. Recently, the use of nanoparticles for asphalt modification has been brought into the hot spot because of their unique properties. Researchers have used various kinds of nanoparticles for enhancing the properties of asphalt, such as Nanosilica, Carbon Nanotubes (CNTs), Carbon Black Nanoparticles (CBNPs), and Graphite Nanoparticles (xGNPs). Graphene Nano-Platelets (GNPs) have commendable mechanical and thermal properties and as a result, their applications can be found in a broad range of fields [2; 3; 4; 5]. A high specific surface area (SSA) and shape ratio (diameter/thickness) are responsible for imparting these properties on GNPs [6]. The strong carbon-carbon bond not only contributes to their exceptional strength but also provides chemical and structural stability [7]. The modification of asphalt with GNPs results in enhanced adhesive forces that increase the moisture resistance of asphalt. Asphalt modified by Graphene Nano-Platelets (GNPs) has been found to have improved mechanical and compaction properties when compared to the conventional asphalt [8]. The two challenges that researchers have to face while working with nanoparticles are their high cost and difficulty in homogeneously dispersing them in an asphalt binder. While working with GNPs, researchers overcame both of these challenges, as GNPs are low in cost and it is easier to achieve their homogeneous dispersion in an asphalt binder [8; 9]. Researchers use a wet mixing technique to disperse nanoparticles in the binder. Nanoparticles are first dispersed in the solvent using a mechanical stirrer and then are mixed with the binder using a high shear mixer. The commonly observed issue with the wet mixing technique is that, if the solvent does not evaporate completely from the binder, it compromises the properties of the binder [1]. The usage of the solvent and the high shear mixer adds to the extra cost, as well as increases the processing time. On the other hand, it is comparatively easy to disperse GNPs in the asphalt binder, as no solvent or shear mixer is required. This makes the industrial application of GNPs favorable. In order to evaluate a pavement, a structural and functional analysis of it is carried out. The structural performance is related to the pavement's strength and capacity to carry loads and traffic flow during its service life. The functional performance relates to the roughness of the pavement's surface. The skid resistance is an important parameter of the functional performance when it comes to the safety of the pavement. It is influenced by the micro-texture and the macro-texture of the pavement. The micro-texture affects the skid resistance in the pavement's early life, whereas the macro-texture influences the skid resistance over the service life of the pavement. To study the micro-texture and macro-texture of asphalt, Scanning Electron Microscopy and a British Pendulum Skid Resistance Tester are used. The structural and functional performances are inter-dependent.