Table 4 gives the average and coefficient of variation (shorted as COV) of the mechanical properties, such as failure load, flexural rigidity and shear rigidity. From Table.4, it can be seen that all the COV of experimental data are less than 8%, so the experiment is reasonable and credible.
The typical curves of load–displacement are shown in Figs. 7 and 8. Fig. 7 shows the typical load–displacement curve for each