## 1 Introduction  
Continuously reinforced concrete pavement (CRCP) is an excellent rigid pavement solution for high priority routes with long-life performance and minimum maintenance [1, 2, 3, 4, 5, 6]. In this type of pavement structure, the continuous longitudinal steel bars are provided throughout the entire length of the concrete slab without any transverse joints to hold the randomly occurring transverse cracks tightly together which ensures that the pavement acts as a continuous system [7]. Therefore, CRCP's performance is mainly dependent on the development of transverse crack patterns [8, 9, 10, 11, 2]. Inspired by the experience of CRCP in the United States, Belgium has been using CRCP to build the highly trafficked roadways since 1970. The proponents of Belgium's CRCP cite a long-lasting pavement solution with minimum overall lifecycle cost. However,the cluster formation in the transverse crack patterns could not be effectively eliminated. Regular field observations of the crack developments on CRCPs in Belgium indicate the low mean crack spacing of transverse crack patterns with a high percentage of cluster crack formation [5; 9; 12; 13; 14; 15]. Large-scale field and laboratory testing of various pavement sections in the United States have revealed that the majority of punch-out distress occurs in CRCP that exhibits a transverse crack pattern of spacing ranging between 0.3 m and 0.6 m and especially in the narrowly spaced crack patterns [16; 17]. Despite the crack cluster formation, Belgium's CRCP following the current standard design concept exhibits excellence performance. However, the risk of punch-out distress is still pertaining due to the development of a short-spaced crack pattern and some CRCP sections have also experienced punch-out in the outer lane of the pavement slab. Therefore, it is essential to optimize the crack spacing pattern in CRCP. The design parameters have been modified in order to eliminate the non-uniformity of the crack pattern. For this purpose, several changes have been made in the standard CRCP design and constructions in Belgium by varying the longitudinal reinforcement ratio, depth of steel layer, the thickness of the concrete slab, concrete mix properties, presence of an asphalt interlayer, and surface finishing, as demonstrated in Table 1[12; 14]. Field observations indicated that the desirable average crack spacing and crack width of fully developed transverse crack pattern could be obtained by these attempts, but it has been challenging to eliminate the crack cluster formation by just adjusting the amount of longitudinal reinforcement, due to the heterogeneous nature of concrete properties, deficiencies in construction process and environmental factors, which could not be effectively controlled by the contractor [5; 6; 9; 10; 11; 12; 13; 14; 15; 16; 17]. Another method usually employed to reduce the non-uniformly spaced cracks is active crack control. Initially, it has been extensively used for the crack induction in rigid pavement structures such as jointed plain concrete pavements (JPCPs). For the very first time, the full-scale test sections of CRCP with active crack control method were constructed in the United States [2; 8; 18; 19; 20; 21]. It was reported that this crack induction method could effectively be employed to induce the regular spaced transverse crack pattern in CRCP. This method has been used either in form of automated tape insertion or the transverse saw-cuts along the width of the pavement. In the United States, the active crack control technique is applied to CRCP by either automated tape insertion or transverse saw-cut through the whole width of a concrete slab. The tape insertion into fresh concrete often poses difficulty in the construction process. While the thorough saw-cut along the entire width of pavement causes the spalling over the pavement surface, which often reduces the ride comfort and also increases the maintenance cost.