# Coefficient of Thermal Expansion of RCA Concrete Made by Equivalent Mortar Volume
## 3 Experimental Tests  
### Mix Design  
The experiment was performed using Type I Portland cement, of which the specific gravity and specific surface area were 3.15 and 3380 cm\({}^{2}\)/g, respectively. The experiment consisted of 23 test series. In test series 2 and 3, Type C fly ash was added at a ratio of 10% relative to the cement. The chemical admixture used in the present experiment was a polycarbonate-based air-entraining agent and a water-reducing agent from a South Korean vendor (Econex Co., Pyeongtaek, Korea). All the aggregates were prepared under saturated-surface-dry conditions.  
The first mix series consisted of 5 mixes having a compressive strength of 35 MPa, which is the standard for manufacturing railway PC sleepers. The tests were performed using the 'RR' aggregates obtained by crushing old PC sleepers. The mix symbols shown in Table 2 are described below. The first letter 'C' means the conventional ACI mix design, and the letter 'E' means the EMV mix design. The following letters 'NR' mean the crushed natural aggregate used for railway sleepers. As described above, 'RR' means RCA produced  
\begin{table}
\begin{tabular}{c c c c c c c c c c c c} \hline \hline \multirow{2}{*}{**Test Series**} & \multirow{2}{*}{**Mix**} & \multirow{2}{*}{**W/C**} & \multirow{2}{*}{**S/a**} & \multirow{2}{*}{**RCA wt \%**} & \multicolumn{6}{c}{**Mix Proportions (kg/m\({}^{3}\))**} \\ \cline{6-11}  & & & & & **W** & **C** & **S** & **F/A** & **NCA** & **RCA** & **Admixture** \\ \hline \multirow{6}{*}{\(1\)} & CNR & 0.39 & 45.3 & 0 & 187 & 480 & 739 & - & 894 & 0 & 4.80 \\ \cline{2-11}  & CRR68 & 0.39 & 46.5 & 68 & 187 & 480 & 739 & - & 275 & 575 & 4.80 \\ \cline{2-11}  & CRR33 & 0.39  
from railway sleepers. CRR68 and CRR33 represent the mixes prepared by respectively replacing 68% and 33% of the total coarse aggregates with the RR recycled aggregates. 'ERR68' in ERR68 and ERR68-2 means that the mixes were prepared using EMV mix design by replacing 68% of the aggregates with the 'RR' recycled aggregates. In addition, '-2' is a scale factor meaning that 1/2 of the RM suggested by the modified EMV mix design was treated with aggregates, and the remaining 1/2 was considered as mortar [42].  
The second mix series consisted of 5 mixes prepared using the 'RP' recycled aggregates produced from old PC culverts. The conventional ACI mix design and the EMV mix design were also applied to the second mix series. The CRP and ERP series of mix series 2 were prepared respectively by using concrete in which the RP recycled aggregate was coated with a cement paste dissociation agent for chloride penetration resistance, and concrete to which cement paste dissociation agent was not applied [43].  
The third mix series consisted of 4 mixes. The first three mixes were prepared by applying the same mix design as in the second mix series, and the fourth was prepared by using the 'RA' recycled aggregate to compare the physical properties between the different types of aggregate.  
A pan mixer that allows for mixing at a volume of 60 L was used to perform the experiment in a laboratory located at Hongik University, Korea. The coarse aggregate and fine aggregate were added to the mixer and mixed together for about 30 s. Then, cementitious materials were further added and stirred for 30 s. After that, admixtures, carefully diluted in water, were added and mixed for 2 min.