# Long-Term Behavior of Concrete Containing Wood Biomass Fly Ash
## 2 Materials and Methods
### Testing Methods  
The following concrete properties were measured in the fresh state: consistency by slump test (EN 12350-2:2019), density (EN 12350-6:2019), air content (EN 12350-7:2019), and temperature [39; 40; 41]. The concrete was compacted on a vibrating table. After compaction, \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Property** & **CEM** & **WFA1** & **WFA2** \\ \hline P\({}_{2}\)O\({}_{5}\) & 0.22 & 1.40 & 1.97 \\ Na\({}_{2}\)O & 0.85 & 2.12 & 0.57 \\ K\({}_{2}\)O & 1.25 & 5.28 & 8.10 \\ CaO & 59.80 & 18.58 & 57.93 \\ MgO & 2.01 & 3.68 & 6.17 \\ Al\({}_{2}\)O\({}_{3}\) & 4.94 & 12.42 & 3.14 \\ TiO\({}_{2}\) & 0.23 & 1.21 & 0.13 \\ Fe\({}_{2}\)O\({}_{3}\) & 3.15 & 4.78 & 2.1 \\ SiO\({}_{2}\) & 21.88 & 49.34 & 18.19 \\ SO\({}_{3}\) & 3.33 & 1.17 & 1.70 \\ Pozzolanic oxides (SiO\({}_{2}\) + Al\({}_{2}\)O\({}_{3}\) + Fe\({}_{2}\)O\({}_{3}\)) & 29.97 & 66.54 & 23.43 \\ Alkalis (Na\({}_{2}\)O + 0.658 K\({}_{2}\)O) & 1.67 & 5.59 & 5.90 \\ LOI (at 950 \({}^{\circ}\)C) & 3.6 & 6.0 & 3.0 \\ pH & 12.9 & 12.9 & 13.2 \\ Density & 3.1 & 2.0 & 2.7 \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Chemical composition and density of the cement and WFA. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Mix Designation** & **M0** & **M1** & **M2** & **M3** & **M4** \\ \hline Cement (kg) & 400 & 340 & 280 & 340 & 280 \\ WFA cement replacement (\%) & 0 & 15 & 30 & 15 & 30 \\ WFA content (kg) & 0 & 60 & 120 & 60 & 120 \\ Cement + WFA (kg) & & & 400 & & \\ w/(cem. + WFA) ratio & & & 0.5 & & \\ Water (kg) & & & 200 & & \\ Aggregate (kg) & 1831 & 1802 & 1780 & 1805 & 1796 \\ Fine aggregate (kg) & 652 & 641 & 634 & 642 & 639 \\ Coarse aggregate (kg) & 1179 & 1161 & 1146 & 1163 & 1157 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Composition of the concrete. the specimens were stored in a room with a temperature of 22 \(\pm\) 2 \({}^{\circ}\)C and covered with a plastic sheet. After 24 h, the specimens were demolded and moved to a curing room where they were cured in air at a temperature of 20 \(\pm\) 2 \({}^{\circ}\)C and a relative humidity of \(>\)95%. All specimens for the fresh and hardened concrete tests were from the same batch. Concrete compressive strength was measured on concrete cubes with a side length of 150 mm at 28 days of age using a standardized method (EN 12390-3:2019) [42]. In addition, compressive strength was tested on specimens cut from prisms used to measure the drying shrinkage. The main reason for this additional test was the increase in length found in the specimens from the M4 mix. From each prism, three concrete cubes with a side length of 10 cm were sawn (Figure 1a). Thus, a total of nine specimens from each mix were tested. At the time of testing, the specimens were 2 years old. The compressive strength measured on cubes with a side length of 10 cm was converted to the strength of a 15 cm cube by multiplying by the coefficient 0.95. The measurements of capillary absorption and gas permeability were performed on cylindrical specimens with a diameter of 150 mm and a height of 50 mm, obtained by sawing from a standard cylinder with a diameter of 150 mm and a height of 300 mm. Before sawing, the concrete cylinders were cured in a curing room for 28 days. Upper and bottom slices of the cylinder were not tested to avoid the effects of different boundary conditions. For capillary absorption measurements, the side surface in contact with water was coated with epoxy resin (Figure 1b). Before testing, the specimens were oven-dried at a temperature of 105 \(\pm\) 5 \({}^{\circ}\)C until the change in mass was less than 0.5 g (\(\approx\)0.025% of mass) for two consecutive weighings, and then allowed to cool to ambient temperature in a sealed container. Specimens for capillary absorption measurement were placed on cylindrical rods in a water container, and the water level was adjusted so that the bottom of the specimens was immersed 2-5 mm into the water. The mass of the specimens was measured at intervals of 5, 15, 30, 60, 120, 240, and 1500 min.