# Intensified Pozzolanic Reaction on Kaolinite Clay-Based Mortar
## 2 Experimental  
### Materials  
The scanning electron microscope (SEM, JSM-7800F Prime from JEOL Ltd., Tokyo, Japan) images of all used materials are shown in Figure 1. The chemical compositions determined by X-ray fluorescence (XRF-1700, Shimadzu, Tokyo, Japan) are summarized in Table 1. Kaolinite clay was obtained from Gochang-goon, Chonnam, Korea. As shown in Table 1, the main oxide components of the clay are SiO\({}_{2}\) (55.34%), Al\({}_{2}\)O\({}_{3}\) (22.33%), and Fe\({}_{2}\)O\({}_{3}\) (8.43%), while the hydrated lime is mainly composed of CaO (74.51%).  
\begin{table}
\begin{tabular}{c c c c c c c c c c c c} \hline \hline \begin{tabular}{c} **Chemical** \\ **Composition** \\ \end{tabular} & \begin{tabular}{c} **SiO\({}_{2}\)** \\ \end{tabular} & \begin{tabular}{c} **Al\({}_{2}\)O\({}_{3}\)** \\ \end{tabular} & \begin{tabular}{c} **TiO\({}_{2}\)** \\ \end{tabular} & \begin{tabular}{c} **Fe\({}_{2}\)O\({}_{3}\)** \\ \end{tabular} & \begin{tabular}{c} **MgO** \\ \end{tabular} & \begin{tabular}{c} **CaO** \\ \end{tabular} & \begin{tabular}{c} **Na\({}_{2}\)O** \\ \end{tabular} & \begin{tabular}{c} **K\({}_{2}\)O** \\ \end{tabular} & \begin{tabular}{c} **MnO** \\ \end{tabular} & \begin{tabular}{c} **P\({}_{2}\)O\({}_{5}\)** \\ \end{tabular} & \
\begin{tabular}{c} **LOI\({}^{\text{1}}\)** \\ \end{tabular} &
\begin{tabular}{c} **Total** \\ \end{tabular} \\ \hline Kaolinite clay & 55.34 & 22.33 & 1.04 & 8.43 & 0.52 & 1.46 & 0.10 & 2.49 & 0.07 & 0.10 & 8.02 & 99.91 \\ Hydrated lime & 0.57 & 0.54 & 0.01 & 0.14 & 1.12 & 74.51 & 0.01 & 0.12 & 0.004 & 0.01 & 23.00 & 100.03 \\ Silica fume & 96.90 & 0.29 & 0.01 & 0.15 & 0.18 & 1.54 & 0.16 & 0.64 & 0.03 & 0.05 & 0.02 & 99.97 \\ \hline \hline \end{tabular}
\end{table}
Table 1: Oxide compositions of used materials (wt %).  
The particle size distributions of kaolinite clay, hydrated lime, and SF are presented in Figure 2, which were determined by laser diffraction method using Mastersizer 3000 (Malvern Instruments, Malvern, UK). Used SF (SiO\({}_{2}\) > 96.9%) has a density of 2.2 g/cm\({}^{3}\) and specific surface area of 200,000 cm\({}^{2}\)/g. In this study, the particle size distribution of SF was measured again using image-processing technique to correct its agglomeration effect during the laser diffraction measurement [35]. To obtain more accurate particle size distribution of SF, 20 SEM images containing total 3720 SF particles were analyzed under various magnifications (30,000\(\times\)-100,000\(\times\)). The obtained new distribution curve of SF is added in Figure 2. The laser diffraction method could not detect the particles smaller than 100 nm (except for very fine particles of 5-11 nm) due to its agglomeration effect. Thus, the highest volume density is formed at 265 nm (Figure 2a); while image-processing method detected the particles between 40-100 nm and yielded the highest density peak at 172 nm. This comparison reveals that a significant portion of small SF particles cannot be detected and the particle size can be overestimated from the laser diffraction method.  
The fine aggregate satisfies the international organization for standardization (ISO) standards [36] which regulates that SiO\({}_{2}\) contents are no less than 98% and the particle size is ranged between 80 \(\upmu\)m and 2 mm.