## 1 Introduction
Composite slab systems have become increasingly popular over the last few decades because of the advantages of merging the two building materials, profiled steel sheets and concrete. The profiled steel sheet is integral in reinforcing the concrete and serves as a secure scaffolding platform for construction workers during the construction stage, thus saving time and cost [27; 28]. Compared to other alternative construction techniques, composite steel-concrete structures are more cost-effective, as they require less construction time and reduced cross-sectional areas [29]. Three main failure modes (flexural failure, vertical shear failure and longitudinal shear failure) have been identified in composite slab systems under the bending moment load [30]. Out of three dominant failure modes, the composite profiled slab system is more prone to longitudinal shear failure than the other two failure modes [31]. The bond strength of a composite slab depends on the efficiency of chemical adhesion, mechanical interlocks, and frictional resistance [27; 28; 32; 33; 34; 35; 27; 36]. The chemical adhesion bond between concrete and the profiled deck is initially responsible for transferring the longitudinal shear forces and inducing a resistance that prevents the occurrence of longitudinal slip [37; 38]. The high shear forces lead to bond strength degradation, and consequently, the significance of the interface embossments at profiled steel sheets emerges by hindering the rapid interface slippage [39; 40]. The frictional bond at the concrete-profilied steel sheet interface is induced during the slippage process, due to the applied pressure by the weight of the hardened concrete slab. The variance in properties between concrete (brittle material) and profiled steel sheet (ductile material), in terms of plastic deformation, results in an inefficient steel-concrete shear bond that leads to brittle failure and low durability of the composite structure [28]. Therefore, a more ductile property of hardened concrete results in a better bond performance of the profiled composite slab system. The transfer of longitudinal shear forces at the concrete-profilied steel sheet interface has been identified as complex to be mathematically modelled. Small-scale tests [30; 39; 50; 51] have been used as an alternative to full-scale bending tests, due to their simplicity and lower construction cost. In the last few decades, different small-scale push test set-ups have been designed to measure and understand the composite interaction behaviour of composite slabs. Some researchers favoured the vertically loaded set-up [38,42,44,48], where profiled steel sheets sandwiched normal concrete, as shown in Figure 1a-c or encased the profiled steel sheets symmetrically, as shown in Figure 1d. However, concrete delamination, handling issues and local buckling were experienced in vertical specimens with lengths over 1 m [38]. Other studies adopted horizontal-loaded test setups [45,51]. Concrete is cast on the profiled steel sheet, so the concrete self-weight reflects the composite interaction at the  
Figure 1: Small-scale test set-ups (dimensions are in mm). (**a**) [PERSON] (1987). (**b**) [PERSON] (1998). (**c**) [PERSON] (2016a). (**d**) [PERSON] (1988). (**e**) [PERSON] (1993). (**f**) [PERSON] et al. (2021a). (**g**) [PERSON] et al. (2021a). concrete-steel interface. Constant and variant clamping forces were applied vertically on the hardened concrete to measure its effect on the frictional resistance. However, a few factors were not adequately simulated in the push tests, including the influence of slab slenderness, frictional resistance provided due to end supports, bending curvature and tensile straining in profiled sheets [50]. As a result, a small-scale block bending test, as shown in Figure 1e, was developed by [PERSON] (1993) [52] to overcome the observed drawbacks. Nevertheless, the bending effect was not adequately performed, due to the specimen's small length and the test equipment's nature.