## 3 Experimental Results  
### CTE Tests  
The measured CTE values for the 40 specimens across the eight concrete mixtures are presented in Table 3. The effect of aggregate volume on CTE is visualized in Figure 4 where mixtures were prepared with a low volume of coarse aggregate and high volume of fine aggregate and Figure 5 with mixtures containing a high volume of coarse aggregate and low volume of fine aggregate. In Figure 4, the average CTE of specimen D-Ns-2 is similar to that of specimen G-Ns-2, with specimen D-Ms-2 similar to specimen G-Ms-2. The concrete specimens with natural sand produced higher CTEs than those with manufactured sand. For concretes with a low volume of coarse aggregate, the influence of the coarse aggregate type on the CTE appears to be insignificant, which is in agreement with a previous study [10]. However, the type of fine aggregate has a greater influence on the concrete's CTE. For the dolomite specimens, the range of the average CTE was 8.3 to 8.5 \(\mu\epsilon/^{\circ}\)C for concrete mixtures with manufactured sand and 9.0 to 9.7 \(\mu\epsilon/^{\circ}\)C with natural sand (see Table 3). Similarly, for concrete mixtures containing granite as the coarse aggregate, the average CTE ranges from 7.9 to 8.3 and 8.8 to 9.7 \(\mu\epsilon/^{\circ}\)C for of the manufactured and natural sand, respectively. Figure 3: Test setup for the determination of the coefficient of thermal expansion (CTE) of the cylindrical concrete specimens. The increase in the CTE for mixtures containing natural sand is a result of the siliceous aggregate generally having a higher CTE than granite-based fine aggregates. [PERSON] et al., reported a CTE study using mortar specimens with different types and varying amounts of fine aggregates that found the CTE increases with increasing volume of siliceous sand and decreasing volume of limestone sand [7]. Similar findings reported that quartz (SiO\({}_{2}\)) has the highest CTE among common minerals (11.5-12.0 \(\mu\epsilon/^{\circ}\)C), while calcite has the lowest (4.5-5.0 \(\mu\epsilon/^{\circ}\)C) [26]. \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline \multirow{2}{*}{**Mixture ID**} & \multicolumn{3}{c}{**CTE (\(\mu\epsilon\)/\({}^{\circ}\)C)**} & \multirow{2}{*}{**Mixture ID**} & \multicolumn{3}{c}{**CTE (\(\mu\epsilon\)/\({}^{\circ}\)C)**} \\ \cline{2-3} \cline{5-8}  & **Heating** & **Cooling** & **Average** & & **Heating** & **Cooling** & **Average** \\ \hline \multirow{4}{*}{D-Ms-1} & 8.3 & 8.5 & & & 7.7 & 7.9 & \\  & 8.6 & 8.8 & & & 7.9 & 8.3 & \\  & 8.5 & 8.6 & (0.07 *) & G-Ms-1 & 7.7 & 7.9 & \\  & 8.3 & 8.6 & & & 7.9 & 8.3 & \\  & 8.3 & 8.5 & & & 7.9 & 8.1 & \\ \hline \multirow{4}{*}{D-Ms-2} & 8.1 & 8.5 & & & 8.1 & 8.3 & \\  & 8.3 & 8.6 & & & 8.1 & 8.5 & \\  & 8.1 & 8.5 & (0.05 *) & G-Ms-2 & 8.1 & 8.5 & \\  & 8.3 & 8.6 & & & 8.1 & 8.5 & \\  & 7.9 & 8.3 & & & 8.3 & 8.5 & \\ \hline \multirow{4}{*}{D-Ns-1} & 8.8 & 9.2 & & & 8.8 & 9.0 & \\  & 9.0 & 9.4 & 9.0 & & 8.8 & 9.0 & \\  & 8.8 & 9.2 & (0.15 *) & G-Ns-1 & 8.8 & 9.0 & \\  & 8.8 & 9.4 & & & 8.6 & 9.0 & \\  & 8.8 & 9.0 & & & 8.6 & 8.8 & \\ \hline \multirow{4}{*}{D-Ns-2} & 9.5 & 9.9 & & & 9.7 & 9.9 & \\  & 9.7 & 9.9 & 9.7 & & 9.7 & 9.9 & \\ \cline{1-1}  & 9.5 & 9.7 & (0.18 *) & G-Ns-2 & 9.7 & 9.7 & \\ \cline{1-1}  & 9.5 & 9.9 & & & 9.5 & 9.7 & \\ \hline \hline \end{tabular} The temperature range for CTE measurement is from 10 \({}^{\circ}\)C to 50 \({}^{\circ}\)C. * Standard deviation.  
\end{table} 
Table 3: Measured and average CTE values. Figure 4: Effect of low volume of coarse aggregate and high volume of fine aggregate on concrete CTE. The EDX results, as will be discussed in a later section, confirm the natural sand had a much higher Si content than the manufactured sand. For concrete mixtures containing the high-volume of coarse aggregate, as shown in Figure 5, mixtures containing natural sand had higher CTE values than those with manufactured, regardless of the type of coarse aggregate.