## 3 Results and Analysis
### Thermal Conductivity Analysis  
(1) Changes due to mineral admixture  
As shown in Table 6, the K value of the controlled sample (MA0) was the highest it is 0.484 kcal/m.h. \({}^{\circ}\)C, while the K values of the samples containing mineral admixtures were between 0.385 and 0.482 kcal/m.h. \({}^{\circ}\)C, corresponding to 79.5-99.6% of that of the controlled sample. This indicates that replacing cement with mineral admixtures can improve concrete heat resistance, possibly because the cement content is decreased. Besides altering concrete physical properties, such as the unit weight, water absorption ratio, and porosity ratio, the inherent hydration reactions and products would affect the concrete thermal conductivity. Figure 10 shows the thermal conductivity after replacing cement with FA, and the K values of FA10 and FA30 were 87.2% and 79.5% of that of the controlled sample, respectively. Fly ash will have a pozzolan reaction with CH in cement paste when water is present. Besides consuming CH to form C-S-H gel to fill pores, FA replaces space originally occupied by CH, indirectly reducing the thermal conductivity and increasing concrete thermal properties [70]. The K values of BFS10 and BFS30 reached 99.6% and 87.6% of that of the controlled sample, respectively. In particular, the difference between the thermal conductivity of BFS10 and the controlled sample was insignificant, possibly because the chemical contents, hydration reaction rates, hydration products, and specific weight of BSF are similar to those of cement. The K values of DLS10 and DLS30 were 82.0% and 85.3% of that of the controlled sample, respectively. The K value of DLS30 was higher than that of DLS10, possibly because the addition of DLS reduces the cement content, but the CaO that it contains is also one of the factors affecting the concrete thermal efficiency [71]. Thus, DLS would produce CaCO\({}_{3}\) after hydration and increase the production of CaCO\({}_{3}\)[72]. In the glass powder group, the thermal conductivity of GLP10 and GLP30 dropped 18.2% and 17.8%, respectively, indicating that the addition of GLP can consume the cement hydration product CH and increase SiO\({}_{2}\) involved in reactivity [73], as well as reduce the thermal conductivity of concrete [74]. As shown in Figure 11, the K value of BFS30 was the highest among the samples with a 30% replacing ratio, even higher than that of FA10, DLS10, and GLP10, indicating that its impact on thermal conductivity is smaller. The K value of FA30 was the smallest among all the samples, indicating that its heat insulation is the best. \begin{table}
\begin{tabular}{c c c c c c c c c c} \hline \hline \multirow{2}{*}{**Sample**} & \multirow{2}{*}{**MA0**} & \multicolumn{2}{c}{**FA (\%)**} & \multicolumn{2}{c}{**BFS (\%)**} & \multicolumn{2}{c}{**DLS (\%)**} & \multicolumn{2}{c}{**GLP (\%)**} \\ \cline{3-10}  & & **10** & **30** & **10** & **30** & **10** & **30** & **10** & **30** \\ \hline TC (kcal/m.h. \({}^{\circ}\)C) & 0.484 & 0.422 & 0.385 & 0.482 & 0.424 & 0.397 & 0.413 & 0.396 & 0.398 \\ Unit Weight (kg/m\({}^{3}\)) & 1406 & 1375 & 1315 & 1396 & 1350 & 1287 & 1308 & 1397 & 1313 \\ Absorption (\%) & 4.41 & 5.61 & 7.85 & 4.62 & 5.61 & 6.13 & 8.93 & 6.07 & 7.22 \\ \hline \hline \end{tabular}
\end{table} 
Table 6: Thermal conductivity of MLAC. * Differences in unit weight  
As shown in Table 6 and Figure 12, the unit weight of the lightweight aggregate concrete varies with mineral admixture type. Heavier unit weights did produce greater thermal conductivity. When the  
Figure 11: Thermal conductivity of MLAC with mineral admixtures 10% and 30%. Figure 10: The relationship between thermal conductivity and the replacement of mineral admixtures. unit weight dropped from 1406 kgf/m\({}^{3}\) to 1315 kgf/m\({}^{3}\), which is a 6.92% reduction, the thermal conductivity also fell from 0.484 to 0.385 kcal/m.h. \({}^{\circ}\)C and it is reduced by 25.7%, which confirmed the findings of [PERSON] et al. [74]. Concrete thermal conductivity is related to density.