# Feasibility of Developing Sustainable Concrete Using Environmentally Friendly Coarse Aggregate
## 3 Experimental Procedure
### Testing  
The compressive strength test was conducted in accordance with AS 1012.9 [54] using MTS compression testing machine by applying a load of 20 MPa/min. Four specimens tested for each data point. Modulus of elasticity and Poisson's ratio were obtained using Technotest compression testing machine coupled with compressometer and extensometer at a constant loading rate of 0.25 MPa/sec in accordance with AS 1012.17 [55]. AS 1012.12.2 standard [53] was used to identify the reported dry densities. The four point bending flexural strength test was conducted using MTS compression testing machine by applying a load of 1 MPa/min with respect to AS 1012.11 [57]. The splitting tensile strength test was conducted in accordance with AS 1012.10 by applying a loading rate of 1.5 MPa/min. The water absorption and apparent volume of permeable void (AVPV) percentage is measured in  
\begin{table}
\begin{tabular}{c c c c c c c c c c c} \hline \hline \multirow{2}{*}{**Material**} & \multicolumn{8}{c}{**By Weight (\%)**} \\ \cline{2-11}  & **SiO\({}_{2}\)** & **Al2O\({}_{3}\)** & **Fe2O\({}_{3}\)** & **CaO** & **P2O\({}_{5}\)** & **TiO\({}_{2}\)** & **MgO** & **K2O** & **SO\({}_{3}\)** & **MnO** & **Na2O** & \({}^{*}\)**LOI \\ \hline Cement & 22.5 & 4.5 & 0.4 & 66.3 & 0.67 & 0.20 & 0.51 & 0.15 & 2.8 & 0.10 & 0.17 & 1.7 \\ \hline \hline \end{tabular}  
* Loss on ignition (unburnt carbon content).  
\end{table}
Table 1: Chemical composition of Portland cement (PC).  
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Aggregate Property** & **RCA-25** & **RCA-40** & **Basalt Aggregate** & **Standard** \\ \hline Aggregate crushing value & 35.5\% & 30.4\% & 21.2\% & AS 1141.21 [46] \\ Aggregate impact value & 36.1\% & 31.2\% & 21.6\% & VicRoads-RC 37.103 [47] \\ Los Angeles abrasion value & 22.4\% & 25.7\% & 32.7\% & AS 1141.23 [48] \\ Over dry density & 2250 kg/m\({}^{3}\) & 2250 kg/m\({}^{3}\) & 2650 kg/m\({}^{3}\) & AS 1141.4 [49] \\ Water absorption & 6.85\% & 6.55\% & 1.45\% & ASTM C127 [50] \\ Moisture content & 4.30\% & 4.15\% & 0.85\% & VicRoads-RC 253.01 [51] \\ \hline \hline \end{tabular}  
\end{table}
Table 3: Properties of coarse aggregates.  
accordance with AS 1012.21 standard [56]. The \(100\times 200\) mm\({}^{3}\) cylindrical moulds were cut into four equal slices and tested according to the standard. The drying shrinkage test was performed in accordance with AS 1012.13 [58]. The drying shrinkage tests were initiated immediately after the 7 days of water curing and continued until 90 days. All shrinkage specimens were kept in a humidity chamber with a temperature of \(23\pm 2\)\({}^{\circ}\)C and 50% relative humidity throughout the testing period. A portable ultrasonic non-destructive tester with a 54 kHz transducer was used to measure the Ultrasonic Pulse Velocity (UPV) in accordance with ASTM C597 [60]. Readings from two directions were observed in each specimen before averaging to get the final UPV value. Scanning Electron Microscope (SEM) images of the concrete microstructure were obtained from a Quanta 200 SEM by using the backscattered electron imaging mode. Images were taken at 10 mm working distance with 15 eV of energy. The specimens used for the SEM imaging were obtained from concrete specimens by cutting using a diamond saw. SEM samples having dimensions of 10 mm \(\times\) 5 mm \(\times\) 5 mm were prepared using a semiautomatic grinding and polishing machine to produce an even and smooth surface by applying mechanical abrasion up to 3\(\upmu\)m. Samples were kept in a dehumidifier for a period of 24 h prior to applying a carbon coat and mounted with conductive, double-sided carbon tape.