## 3 Results and Discussion
### Analysis of Double Lassel GCCM Characteristics by Concrete Filling Factor  
To analyze the characteristics of double raschel GCCMs in relation to concrete filling rates, three different concrete weights of 530 g, 620 g, and 710 g were used to create Samples-C1 to C6, with the blowing agent addition. Photographs of the concrete cross-sections, both with and without blowing agent addition, are shown in Figure 5. The 530 g filling represents the middle layer of the double raschel GCCM, 620 g fills up to the upper fabric, and 710 g overfills beyond the upper fabric. Samples-C1 to C3 were prepared without the blowing agent addition, while Samples C4 to C6 were cured for a duration of 10 days after 5 wt% of a blowing agent was added. Upon examining the cross-sectional image of Sample-C1, it became evident that despite filling the middle layer of the double raschel GCCM, a reduction in cross-section was observed due to curing shrinkage. Similarly, Sample-C2, which was filled up to the upper fabric layer, exhibited a void in the middle. Particularly, Sample-C3, involving overfilling beyond the upper fabric, showed more extensive curing. Cross-sectional images of both Sample-C1 to C3 and Sample-C4 to C6 were analyzed, and comparisons were made between sections treated with the blowing agent and those without treatment. It is seen that the phenomenon of cross-section reduction attributed to concrete shrinkage during hydration was relaxed through the use of the blowing agent addition at equivalent concrete content levels. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Blowing Agent Content (wt\%)** & **1** & **3** & **5** & **7** & **9** & **11** \\ \hline Volume change (\%) & 6.25 & 9.38 & 11.25 & 15.63 & 18.13 & 18.75 \\ \hline Surface texture & & Smooth & & & Cracked \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Volume change of double raschel GCCM with blowing agent content. Figure 4: Photographs of Surface change of concrete with blowing agent content. Table 3 shows the thickness, filling factor, and bending strength measurements of GCCMs with and without blowing agent addition. For comparing Sample-C1 and Sample-C4, it is seen that the filling rate is nearly 100% when using a concrete filling amount of 530 g with blowing agent addition. However, upon contrasting Sample-C2 and Sample-C4, both characterized by similar filling rates, it is seen that the bending strength slightly decreased in the sample with blowing agent addition, in comparison to the sample without blowing agent addition. This phenomenon can likely be attributed to the formation of bubbles within the concrete due to the blowing agent addition. Figure 6a shows the relationship between bending strength and filling factor, while Figure 6b shows the bending strength with blowing agent addition under equivalent filling amounts. Irrespective of whether the blowing agent was used or not, there was a noticeable trend of increasing bending strength with a higher filling factor of the concrete. Particularly when the concrete filling rate surpassed 100%, the increase in bending strength exceeded 160%, as shown by Sample-C3. From this, it is seen that a concrete filling rate exceeding 100% is essential for the inherent physical properties of double raschel GCCMs to appear. Figure 5: Photographs of cross-sections of double raschel GCCM with blowing agent addition.