# Feasibility of Non-Remanufactured Waste Bottle Glass as Supplementary Cementitious Material
## 2 Methodology
### Mortar Study
#### 2.2.3 The mechanical Strength
Each sample mass was measured before partial water immersion (0 min) and at the following times after contact with water, 5, 10, 20, 30, 60, 90, 120, 180, and 240 min. The following equation determines the sorptivity, S, of each mortar specimen during testing time:  
\[A=A_{0}+S\times t^{0.5} \tag{2}\]  
where \(A_{0}\) (mg/mm\({}^{2}\)) is the water absorbed initially by pores in contact with water, A (mg/mm\({}^{2}\)) is the water absorption by unit area of the mortar specimen's surface from the moment the specimen is dipped in water, and t is the elapsed time from the moment the specimen makes contact with water (in minutes). Rapid Chloride Migration Test  
The NT Build 492 procedure was followed to access the chloride ion penetration resistance. The test was performed at 28 days on three replicate cylindrical specimens  
Figure 5: Mortar resistivity measurement. Figure 6: Water absorption by capillarity conducted in a water bath with an automatically adjusted water level. for each mortar under study (Table 4). Before testing, the samples were vacuum-soaked with a Ca(OH)\({}_{2}\) saturated solution. Afterwards, an electrical potential was applied across each specimen to force the chloride ions in the catholyte solution (10% NaCl) to migrate through them, as shown in Figure 7. In this case, a potential of 25 V was applied, and the test was performed for 24 h. Afterwards, the cylindrical samples were axially split into two halves, and silver nitrate solution (0.1 M) was sprayed on one of the surfaces. This solution precipitated the chloride salt into white silver, as seen in Figure 8.  
Equation (2) allows the calculation of the non-steady-state migration coefficient, D\({}_{\text{nssm}}\):  
\[D_{\text{nssm}}=\frac{0.0239(273+T)L}{(U-2)t}\times\left(x_{\text{d}}-0.0238 \sqrt{\frac{(273+T)Lx_{\text{d}}}{U-2}}\right)\times 10^{-12} \tag{3}\]  
\(T\) is the mean value of the initial and final temperatures in the 0.3 M NaOH solution; \(U\) is the absolute value of the voltage applied (V); \(L\) is the sample thickness (mm); \(t\) is the duration of the test (min); and \(x_{\text{d}}\) is the mean value of the penetration depths (mm). Accelerated Carbonation Test  
The resistance to CO\({}_{2}\) was evaluated according to RILEM CPC-18. Three prismatic specimens (40 \(\times\) 40 \(\times\) 160 mm\({}^{3}\)) were cast for each mortar type (see Table 4). The specimens were water-cured for 14 days and then dried in a controlled environment room  
Figure 8: White silver precipitation of chloride salt. Figure 7: Chloride migration test set-up. (T = 20 \(\pm\) 2 \({}^{\circ}\)C and HR = 50 \(\pm\) 3%) for 14 days. After that, the specimens were exposed to accelerated carbonation in a climatic chamber with a CO\({}_{2}\) concentration of 5 \(\pm\) 0.1%, RH = 60 \(\pm\) 5%, and temperature of 23 \(\pm\) 2 \({}^{\circ}\)C. At the 35 th day of exposure to CO\({}_{2}\), a 1 cm slice thickness was cut from each sample and sprayed with 1% phenolphthalein solution. Exposure to a carbonation environment reduces the pH of the cementitious system mainly due to the reaction of calcium hydroxide with CO\({}_{2}\). As a result, the phenolphthalein solution remains colourless in the carbonated region and red/pink in the non-carbonated region [44]. The risk of alkali-silica reaction occurrence due to waste glass incorporation was monitored according to ASTM C 1567 with two slight modifications [21; 22; 25]. Instead of using the mortar proportioning specified in the standard, the specimens were produced using mortar mix proportions presented in Table 4. In addition, mortars were produced using CEN sand according to EN 196-1.