# Feasibility of Non-Remanufactured Waste Bottle Glass as Supplementary Cementitious Material
## 2 Methodology
### Non-Remanufactured Waste Bottle Glass
#### 2.1.4 Waste Glass Properties  
As refered, Table 1 summarises the physical properties of cement WG, GWG, and AGWG: density (determined by E-64), specific surface (determined according to EN 196-6, Blaine method), and particle size distribution (determined via laser method). The major elements analysis of cement and WG is presented in Table 2 and was determined by FRX.  
As can be perceived from Table 2, WG is mainly composed of siliciium oxide (61%), calcium oxide (11%), and sodium oxide (10%). Based on the literature survey, the percentages of the main constituents of glass do not differ widely, except Al\({}_{2}\)O\({}_{3}\) and CaO. Soda-lime glass comprises approximately 70% silica, 13-17% Na\({}_{2}\)O, and 10% CaO [16; 21; 22; 23]. The WG used in the current work presented less silica and higher calcium content. This might be related to the contaminants still present in WG, giving rise to higher calcium content and LOI (12%, see Table 2) due to organic matter.  
The use of waste glass powder as an SCM for cement-based materials/concrete does not yet have a dedicated standard. As such, the following standards were considered as a benchmark: (a) a general Portuguese standard for pozzolanic materials, NP 4220, and (b) an American standard, ASTM C 618, regarding fly ash and raw or calcined natural pozzolan for cement. The requirements of those standards are explained in Table 3. Bold and/or underlined cells in Table 3 highlight requirements WG did not comply with. Even though WG used in the current research presents a composition similar to natural pozzolan and other waste glasses, the requirements were not met. ASTM C 618 (class N and F) stipulate a minimum content of 70% for the sum of SiO\({}_{2}\) + Al\({}_{2}\)O\({}_{3}\) + Fe\({}_{2}\)O\({}_{3}\). Although not far, WG did not reach 70% of SiO2 + Al\({}_{2}\)O\({}_{3}\) + Fe\({}_{2}\)O\({}_{3}\).  
According to ASTM C 618, the LOI presents a maximum limit of 10% for class N and 6% for classes F and C. Similarly, NP 4220 specifies a maximum LOI of 10%. The LOI of WG did not comply with any of those standards.  
Concerning the sulphate content, an average SO\({}_{3}\) content of 0.48% was obtained for the WG sample, which is very low compared with the benchmarking limits referred by NP 4220 (3.0%) and ASTM C 618 (4.0% minimum limit).  
A maximum chloride content of 0.1% is imposed by NP 4220. The WG was found to have an average chloride of nearly 0.1% (see Table 2). Since waste glass powder will  
\begin{table}
\begin{tabular}{c c c c c c c c c c c c c} \hline \hline \multirow{2}{*}{**Materials**} & \multicolumn{10}{c}{**Chemical Composition (\% by Mass)**} \\ \cline{2-13}  & **SiO\({}_{2}\)** & **CaO** & **Fe\({}_{2}\)O\({}_{3}\)** & **Na\({}_{2}\)O** & **Al\({}_{2}\)O\({}_{3}\)** & **MgO** & **K\({}_{2}\)O** & **TiO\({}_{2}\)** & **P\({}_{2}\)O\({}_{5}\)** & **Cl** & **SO\({}_{3}\)** & **Insoluble Residue** & **LOI** \\ \hline Cement & 20.33 & 63.31 & 3.02 & 0.20 & 4.83 & 1.91 & 0.73 & & 0.05 & 2.85 & 1.03 & 2.28 \\ \hline WG & 60.91 & 10.78 & 1.15 & 9.63 & 2.54 & 1.07 & 0.92 & 0.15 & 0.16 & 0.16 & 0.49 & & 12.27 \\ \hline \hline \end{tabular}
\end{table}
Table 2: Main oxide composition of cement and WG.  
probably be used as partial cement replacement in a percentage lower than 10-20%, chloride content might not be a concern.  
Regarding the physical properties presented in Table 1, the PSDs of WG and AGWG are higher than cement. The d\({}_{90}\) values were 40, 127, and 82 \(\upmu\)m for cement, WG, and AGWG, respectively, and the d\({}_{50}\) values were 13, 26, and 18 \(\upmu\)m. A lower PSD would benefit pozzolanic ability [16; 31; 32; 33; 34; 35; 36; 37; 38] since past research showed that the smaller the particle size, the higher the pozzolanic reactivity of the glass powder particles [39].