## 3 Results and Discussion
### Mass Loss Measurements  
Table 14 shows the percentage mass loss values from TGA (powdered samples) and 25 mm cubes measured by using a balance for GP paste specimens. The average values of the mass loss measurements using the balance were approximately 17% for samples after being exposed to temperatures of both 400 \({}^{\circ}\)C and 800 \({}^{\circ}\)C. The specimens that were subjected to the thermo-gravimetric analysis (TGA showed relatively much lesser losses, with averages of approximately 7.5% and 9.4% for 400 \({}^{\circ}\)C and 800 \({}^{\circ}\)C exposure, respectively. This difference in mass loss percentages could be due to the severe thermal cracking, which could have caused minor corner spalling to occur in the cube specimens, thus resulting in \begin{table}
\begin{tabular}{c c c c c c} \hline \multirow{2}{*}{**Sample ID**} & **Room** & \multirow{2}{*}{**400 \({}^{\circ}\)C**} & \multirow{2}{*}{**800 \({}^{\circ}\)C**} & **Thermal** & **Thermal** \\  & **Temperature** & & & **Cracking 400 \({}^{\circ}\)C** & **Cracking 800 \({}^{\circ}\)C** \\ \hline RPCG 01 & 76.25 & 60.58 & 50.52 & No & No \\ RPCG 02 & 64.54 & 44.43 & 30.58 & No & No \\ RPCG 03 & 38.59 & 21.67 & 14.90 & No & Yes \\ RPCG 04 & 19.55 & 18.34 & 14.42 & No & No \\ Minimum & 19.55 & 18.34 & 14.42 & N/A & N/A \\ Maximum & 76.25 & 60.58 & 50.52 & N/A & N/A \\ \hline \end{tabular}
\end{table} 
Table 13: Average compressive strengths of RPGC cubes. Figure 4: RPC specimens before (**left**) and after (**right**) exposure to elevated temperatures. higher losses. However, it may be noted here that mass measurements taken on bulk samples (i.e., cubes) can be considered to be more reliable than the corresponding ones obtained through TGA runs as inhomogeneity of the samples can be considered to be amplified in mg scales (i.e., in the case of thermograms obtained from the TGA runs). When considering the high initial rate of mass loss can be attributed to the evaporation of physically bound (free) moisture, after which the rate reduces and somewhat stabilizes [25; 56; 57; 58; 59]. The continued loss in mass after the initial steep drop, can be due to the loss of chemically bound water and in part resulting from the decomposition of CaCO\({}_{3}\) (ca. 700 to 800 \({}^{\circ}\)C) within the concrete matrix [57]. The RPGC specimens recorded the lowest percentages in mass losses, from TGA runs and measurements using a balance, as compared to the GP paste specimens. This could be due to the higher percentage of solid particles (and hence lower water loadings) within the RPGC specimens as compared to the GP specimens. Hence, the overall loss of mass is potentially reduced as mass loss can be thought to arise mainly from the loss of moisture. In addition, among the RPGC specimens, RPGC 01 cube specimens recorded to be the densest (i.e., having a density value of 2245 kg/m\({}^{3}\)). This effectively means that a lower \begin{table}
\begin{tabular}{c c c c c} \hline  & **Mass Loss (wt. \%) from TGA** & **Mass Loss (wt. \%) from Weighing** \\
**Sample ID** & **400 \({}^{\circ}\)C** & **800 \({}^{\circ}\)C** & **400 \({}^{\circ}\)C** & **800 \({}^{\circ}\)C** \\ \hline GP 01 & 6.47 & 8.45 & 14.10 & 15.88 \\ GP 02 & 6.59 & 8.09 & 14.61 & 15.34 \\ GP 03 & 7.16 & 8.73 & 14.08 & 14.86 \\ GP 04 & 6.66 & 7.78 & 15.09 & 15.37 \\ GP 05 & 6.73 & 7.84 & 15.08 & 15.79 \\ GP 06 & 7.89 & 10.56 & 22.39 & 21.68 \\ GP 07 & 8.66 & 11.76 & 20.33 & 20.99 \\ GP 08 & 8.36 & 10.69 & 19.27 & 19.52 \\ GP 09 & 8.64 & 10.22 & 19.66 & 19.31 \\ GP 10 & 7.89 & 9.65 & 19.75 & 20.04 \\ Minimum & 6.47 & 7.78 & 14.08 & 14.86 \\ Maximum & 8.66 & 11.76 & 22.39 & 21.68 \\ Average & 7.51 & 9.38 & 17.43 & 17.88 \\ \hline \end{tabular}
\end{table} 
Table 14: Average compressive strengths of RPGC cubes. Figure 5: A plot of average initial and residual compressive strengths of RPGC specimens. percentage of moisture was available for evaporation at elevated temperature levels; hence, would result in lower mass losses.