## 1 Introduction  
According to the law of conservation of energy, radiation of wavelength \(\lambda\) incident upon a material has either been transmitted across the material, has been reflected from its external surface or has been absorbed. The proportions of transmitted, reflected and absorbed energy can be expressed as ratios of the incident energy [1]. Accordingly, transmissivity (\(\
abla_{\lambda}\)), reflectivity (\(\alpha_{\lambda}\)) and absorptivity (\(\zeta_{\lambda}\)) are defined as dimensionless numbers between zero and the unity, according to Equation (1). They are radiative properties of the material. Strictly speaking, Equation (1) is valid exclusively for the case of a single wavelength. Nevertheless, it is acceptable for fairly wide range of wave bands. For instance, the reflectivity, \(\alpha\), for solar radiation, is referred to as the surface albedo. Therefore, surface albedo can be defined as the reflected solar radiation of the material surface divided by the amount incident upon it, and it is one of the main parameters of material surface radiation [2]. Consequently, the value of the reflectivity, \(\alpha\), directly determines the absorptivity of an opaque surface. \[\Psi_{\lambda}+\alpha_{\lambda}+\zeta_{\lambda}=1, \tag{1}\]  
Albedo regulates the surface short-wave absorption for a given solar input. This fact controls the daytime net radiation budget. Consequently, it rules the moisture and thermal climate of the material surface and the surrounding air and land. In particular, the albedo (\(\alpha_{\lambda}\)) is a key surface characteristic and one which can be easily modified by surface treatment. Furthermore, it should be taken into account that some surfaces that are dark colored can reflect large portions of infrared solar radiation. Accordingly, they may also have high albedo values [3]. Modification of the construction material's albedo will invoke a significant climatic chain reaction [4]. The climatic conditions and the layout of the buildings has been a subject of interest since the 1 st century BC, when [PERSON] showed that climatic conditions and the layout of the buildings should be considered by the architects [5]. Currently, it is widely acknowledged that the placement of a building on the landscape gives rise to moisture, thermal, radiative, and aerodynamic variation of the surrounding environment. Although cities occupy just 2% of the Earth's land surface, city dwellers consume about 75% of the world's energy resources [6]. In addition, the urban population is increasing worldwide as more people are leaving the rural areas to move to the cities. Albedo and land surface temperature (LST) are correlated [7], i.e., a high albedo value (high reflection rate of solar radiation) results in lower heat absorption, and therefore, in a lower LST value. Accordingly, the utilization of building materials with high values of albedo can help to reduce heat accumulation within cities [7]. [PERSON] et al. [7] reported a temperature reduction and performance improvement of construction materials for Urban Heat Island (UHI) mitigation in the city of Valladolid (Spain). [PERSON] [8] has argued that mitigation measures can offset the Urban Heat Island (UHI). Furthermore, the use of several simultaneous measures can further offset the UHI, albeit the combined results are not linear and normally smaller than the mere sum of cooling effects from the individual measures. The main methods for retrieving information about Urban Heat Island (UHI) and albedo effect of pavements are numerical modelling, \"in situ\" measurements and remote sensing. The first one is the most widely used method, followed by \"in situ\" measurements and remote sensing [9]. Remote sensing is a promising method for retrieving information about the heat from the Earth's surface covering a large area, where satellites and aircrafts are used to collect images showing the data [10]. Some sensors capture the long- and short-wavelength radiation energy reflected from the Earth's surface [11; 12].