## 3 Test Results and Discussions
### Visual Observation  
After push test completion, the concrete-profiled steel sheet interface of one specimen of each mixture was investigated by separating the concrete block from the profiled steel sheet, as shown in Figure 16. NC40 and NC60 shared the same observations regarding the  
Figure 15: Average load–end slip relationships of the push test specimens. (**a**) Overall behaviour. (**b**) Enlarged behaviour.  
smooth concrete bottom surface, as shown in Figure 16(a1,b2), with no cracks. In addition, the profiled steel sheet was clean, and no concrete powder was left on the softin or ribs, as shown in Figure 16(a2,b2). On the other hand, the SCGC specimen showed a different behaviour for the concrete block bottom and profiled steel sheet interface. For the SCGC specimen, the blue zinc coated covering the profiled steel sheet was primarily wiped off the profiled sheet surface, as shown in Figure 16(c2), and printed on the SCGC interface, as shown in Figure 16(c1), which was not observed in the NC specimens. The observed behaviour indicates that SCGC has a better chemical adhesion bond with profiled sheets than NC.  
The observed behaviour indicates that SCGC has a better chemical adhesion bond with the profiled sheets than NC. For profound visual observation, a diamond saw machine cut through the concrete from the top to the bottom edge around the ribs for the three specimens, as shown in Figure 17. The aim was to ensure that the voids formed due to the interaction between the embossments and concrete were kept intact and not affected by the saw. A crushed SCGC powder was observed around the profiled sheet embossments, as shown in Figure 17c, which indicates a heavy interaction between SCGC and the embossment  
Figure 16: Interface of concrete and steel deck of push-off test specimens. (**a1**) NC40 concrete, (**b1**) NC60 concrete, (**c1**) SCGC concrete. (**a2**) NC40, (**b2**) NC60, (**c2**) SCGC.  
during the push test. There was no observed crushed concrete around the embossments in the NC specimens, as shown in Figure 17a,b. Figure 18 shows the indentions developed in the NC40, NC60 and SCGC samples at the concrete embossment interface. A minor groove was formed along the longitudinal path due to the heavy interaction between SCGC and the embossments, as shown in Figure 18c. At the same time, for NC40 and NC60, an imprint was visible, as shown in Figure 18a,b, indicating less interaction between NC and the embossments than the SCGC specimens. The better composite interaction between SCGC and the embossments can be attributed to the lower concrete hardness that SCGC has compared to NC. The lower SCGC hardness allowed the angular side of the embossment to crush a small amount of concrete during the push test and improve the composite interaction between SCGC and the profiled sheet. Once the chemical adhesion is broken and the concrete block slips into the longitudinal rib direction, the concrete block compresses the embossment within the elastic deformation zone. This deformation is fully recovered in the subsequent concrete void. Hence, there was no deformation observed in the embossment after test completion.  
Figure 17: Visual observations around embossments. (**a**) NC40. (**b**) NC60. (**c**) SCGC.  
Figure 18: Precise observation of indentions in concrete. (**a**) NC40. (**b**) NC60. (**c**) SCGC.