## 2 Materials and Methods  
### Materials  
In this study, ordinary Portland cement CEM I 42.5 R (OPC) was used as a binder for LWC specimens. OPC was produced by JSC \"Akmenes Cementas\" (Akmene, Lithuania)according to the requirements of the EN 197-1 [28] standard. The main characteristics of OPC are presented in Table 1.  
To reduce the viscosity of the Portland cement matrix, a polymeric dispersant (PD), Castament(r) FS 40, was used. PD Castament(r) FS 40 is a spray-dried, free-flowing powder of a polymerisation product based on polyethylene glycol. Castament(r) FS 40 was produced by BASF Construction Solutions GmbH (Trostberg, Germany). The main characteristics of PD are presented in Table 2.  
Metakaolin waste (MKW) is formed during the technological processes required to produce expanded glass and was used as a pozzolanic microfiller. Ten percent of the OPC was replaced with MKW. MKW accelerates the hydration of Portland cement and participates in the pozzolanic reaction with portlandite, formed by the hydration of the main cement minerals. MKW also slightly performs the functions of a superplastic and ensures the formation of fine pores in concrete, increasing its durability. MKW was obtained from the company JSC \"Stiklporas\" (Druskinikai, Lithuania). The main characteristics of MKW are presented in Table 3.  
The air-entraining admixture (AEA) \"UFAPORE TCO\" was used to ensure the formation of small pores in the cement matrix and to hydrophilise the crushed polystyrene foam waste. AEA is an admixture based on sodium alkene sulphonate. AEA was produced at Unger Fabrikker AS (Fredrikstad, Norway). The main characteristics of AEA are presented in Table 4.  
The expanded glass (EG) aggregate of three different fractions (0-2, 4-8, and 8-16 mm) were produced by JSC \"Stiklporas\" (Druskinikai, Lithuania) and used as LWA in LWC. The main characteristics of the EG aggregate are presented in Table 5.  
\begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline
**Specific** & **Bulk Density,** & **Start of** & **End of** & **Max Alkali** & \multicolumn{3}{c}{**Mineral Composition, \%**} \\
**Surface, cm\({}^{2}\)/g** & **g/cm\({}^{3}\)** & **Setting, min** & **Setting, min** & **Content, \%** & **C\({}_{3}\)S** & **C\({}_{2}\)S** & **C\({}_{3}\)A** & **C\({}_{4}\)AF** \\ \hline
4200 & 1.15 & 140 & 190 & 0.8 & 56.64 & 16.72 & 8.96 & 10.59 \\ \hline \end{tabular}
\end{table}
Table 1: Main characteristics of OPC.  
\begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline
**Physical Shape** & **Appearance** & **Bulk Density,** & **PH Value (at 20 \({}^{\circ}\)C),** & **Dosage Recommendation, \%** \\  & **kg/m\({}^{3}\)** & **20\% Solution** & **(in Relation to Weight of Material)** \\ \hline Powder & Yellowish to brown & 300–600 & 6.5 to 8.5 & 0.05 to 0.5 \\ \hline \end{tabular}
\end{table}
Table 2: Main characteristics of PD.  
\begin{table}
\begin{tabular}{c c c c c c c c c c} \hline \hline
**Specific** & **Bulk Density,** & **Size of Particles** & \multicolumn{6}{c}{**Mineral Composition, \%**} \\
**Surface, cm\({}^{2}\)/g** & **g/cm\({}^{3}\)** & **(More than 40 \%),** \% & **SiO\({}_{2}\)** & **Al\({}_{2}\)O\({}_{3}\)** & **Fe\({}_{2}\)O\({}_{3}\)** & **CaO** & **MgO** & **K\({}_{2}\)O + Na\({}_{2}\)O** & **TiO\({}_{2}\)** & **Others** \\ \hline
897 & 0.480 & 8–15 & 46.1 & 37.2 & 1.1 & 0.2 & 0.20 & 0.70 & 0.70 & 13.8 \\ \hline \end{tabular}
\end{table}
Table 3: Main characteristics of MKW.  
In this study, crushed aggregate of polystyrene foam packaging waste containers (CEPW) (0-2 mm), were supplied by \"Virginijus ir Co\" (Plunge, Lithuania) and used to significantly facilitate LWC. The bulk density of the (0-2) mm fraction was 15.0 kg/m\({}^{3}\).