## 1 Introduction  
Concrete is a composite material defined as an artificial stone-like mass produced by mixing binders (cement or lime) with aggregates, water, additives, etc., in a specific ratio. Most concrete consists of Portland cement, aggregates (gravel and crushed stone), and sand, to which water is added. It is a cost-effective material that has good compressive strength and does not crush or break, even under high compressive forces. When used in pavement construction, its special properties require particular care to maintain the strength and serviceability of the pavement [1]. For example, when the first crack appears in a concrete pavement, it is more likely to become a deep crack immediately due to the brittleness of the material [2]. If the crack is not sealed in time, the crack width will increase over time, and the cracked slab will split into independent parts, which may indicate poor load transfer [3]. For this reason, minor rehabilitation measures, such as minor repairs, partial replacement, etc., which may work for asphalt pavements, are not always effective for concrete pavements [4]. Even if it is decided to renew the entire pavement, in a relatively large study area, it is inefficient to select individual slabs for replacement, as this will lead to additional pavement damage in the adjacent undamaged slabs [5]. Another common cause of damage to concrete pavement near edges or corners is the condition of the joints, especially in jointed plain concrete pavement (JPCP). With this type of pavement, the joints must be properly maintained to control the location where cracking may occur [6]. Joints with poor load transfer efficiency (LTE) may indicate poor pavement performance, susceptibility to failure, and lack of cooperation with adjacent slabs [7]. In addition, the effects of environmental factors are critical to the behavior of concrete pavements [8]. Temperature differences across the slab thickness can lead to shrinkage cracking and thus to an increased risk of failure, regardless of the traffic load [9; 10]. For this reason, both material quality control (i.e., correct mix composition, control of voids, etc.) and structural aspects (e.g., curing time of the material, climatic conditions during paving, etc.) are equally important from the beginning of the service life of a concrete pavement [11; 12]. In addition, road pavements are an important means of transportation within a nation and need to be strategically monitored and continuously maintained. However, developing pavement rehabilitation plans is always a challenge, simply due to budget constraints. Accurately determining the pavement condition on site is again the first and most important measure for rational pavement management [1]. The use of nondestructive testing (NDT) dominates in the field of pavement condition assessment due to its non-invasive nature [8; 13; 14]. Deflection tests with the well-established falling weight deflectometer (FWD) are usually performed at different locations of a concrete slab, e.g., in the center, at the edges, and in the corners [1; 15; 16]. The evaluation of deflection changes within a single slab provides information about possible problems with the durability of the pavement. The FWD is also a powerful tool for assessing the ability of the pavement to transfer loads on both sides of a joint or crack. Given these capabilities, there are numerous studies that support the use of the FWD for the condition assessment of concrete pavements [17; 18; 19]. However, when evaluating layer properties by back-calculating the stiffness profile, concerns have been raised about the efficiency of modeling the deflection profile, especially for aged or cracked pavements [20]. More recently, continuous deflection measurements have also been carried out using the rolling wheel deflectometer (RWD) [18; 21; 22]. However, the key operating principles of the RWD have yet to be fully understood and adopted by engineers, as the FWD is versatile and has gained worldwide acceptance.