## 1 Introduction  
Early-age cracking inevitably occurs in concrete pavements because of the temperature differences and stress development during the hardening process of concrete [1]. For this reason, transverse joints in jointed plain concrete pavement (JPCP) are intended to relieve the stresses in the concrete slab caused by environmental loading. Severe distress in JPCP includes the spalling and faulting over these joints, which increase the maintenance and rehabilitation cost and associated user inconvenience due to traffic control. The continuous joints repairing throughout the life span of JPCP originates the concept of continuously reinforced concrete pavement (CRCP) [2; 3; 4; 5; 6; 7]. The original intention of CRCP is to eliminate the transverse joints and enhance the pavement service life with minimal maintenance [8; 9; 10; 11; 12; 13; 14]. CRCP contains steel bars continuously in the longitudinal direction and no gaps for transverse joints. Hence, the cracking is allowed to occur as a result of the volumetric changes in the concrete pavement slab under environmental loads. The continuously placed longitudinal steel bars are intended to hold the cracks so tight that the pavement concrete slab behaves like a continuous system. As CRCP is constructed without any intended joints, no repairing and maintenance of joints are required. Consequently, the overall life cycle cost of CRCP is less than that of JPCP. The proponents of CRCP cite durability, sustainability, and low maintenance cost, which made it as durable pavement requiring little maintenance. For the past few decades, most of the countries in Europe including Belgium have been using CRCP to build high priority and heavily loaded roadways [9; 15; 16; 17; 18; 19; 20; 21; 22; 23; 24]. The performance of CRCP is mainly dependent on the development of early-age crack pattern caused by environmental loading [10; 11; 12; 25; 26; 27; 28; 29; 30; 31; 32]. Different crack induction methods have been adopted to induce cracks from the designated locations, aiming to reduce the probability of cluster crack formation in the transverse crack pattern, which eventually leads to the development of severe distress such as punch-out in CRCP. In Belgium, the active crack control method in the form of transverse partial surface saw-cuts at one of the outer edges of the concrete slab has been proven as the most effective crack induction method for inducing the cracks from pre-determined locations (saw-cut tips) of CRCP [13; 15; 26; 27]. As CRCP is designed to crack naturally, randomly occurring cracks such as divided cracks, Y cracks, diagonal cracks, and narrowly spaced cluster cracks inevitably take place during early age, and are held tightly by the continuous longitudinal steel bars. Therefore, the main role of continuous longitudinal reinforcement in CRCP is to prevent excessive crack openings for fulfilling the serviceability requirements within the desired limits [8; 29; 33; 34; 35; 36; 37; 38; 39; 40]. Hence, the initial construction cost of CRCP is always much higher than that of other types of concrete pavements because of the larger amount of longitudinal steel throughout the length of the concrete slab. The effective crack inductions over the designated locations in the concrete slab could reduce the substantial amount of continuous longitudinal steel without compromising the pavement performance and intended service life of CRCP; consequently, the initial construction cost of CRCP could become comparable to those of other concrete pavements. A state-of-the-art concrete pavement structure called advanced reinforced concrete pavement (ARCP) is a concrete slab reinforced with a combination of continuous and partial longitudinal steel bars throughout the length of the pavement [37]. Continuous longitudinal steel bars are replaced with partial steel bars at the crack locations to decrease the total amount of reinforcement and corresponding initial construction cost.