# Application of Foundry Wastes in Eco-Efficient Construction Materials: A Review
## 6 Conclusions and Future Perspectives
\begin{table}
\begin{tabular}{c c c c} \hline \hline
**Authors** & **Foundry Waste** & \begin{tabular}{c} **Construction** \\ **Material** \\ \end{tabular} & **Main Results** \\ \hline [PERSON] et al. [89] & \begin{tabular}{c} Copper Slag and \\ Ground Granulated \\ Blast Furnace Slag \\ \end{tabular} & Concrete & \begin{tabular}{c} The replacement of up to 40\% of copper slag in \\ concrete with 30\% GGBFS improved strength and \\ durability, but higher replacements reduced \\ performance due to increased porosity. \\ \end{tabular} \\ \hline [PERSON] et al. [108] & \begin{tabular}{c} Ground Granulated \\ Blast Furnace Slag and \\ Waste Foundry Sand \\ \end{tabular} & Concrete & \begin{tabular}{c} The substitution of Portland cement with \\ alkali-activated GGBFS met the standards for strength \\ and water absorption, immobilizing heavy metals and \\ preventing environmental threats. \\ \end{tabular} \\ \hline [PERSON] et al. [109] & \begin{tabular}{c} Ground Granulated \\ Blast Furnace Slag and \\ Waste Foundry Sand \\ \end{tabular} & Lightweight & \begin{tabular}{c} The addition of calcined WFS increased the \\ compressive strength of the concrete in the early days, \\ but there was a slight decrease in strength at later \\ ages. \\ \end{tabular} \\ \hline [PERSON] et al. [110] & \begin{tabular}{c} Ground Granulated \\ Blast Furnace Slag and \\ Waste Foundry Sand \\ \end{tabular} & Concrete & \begin{tabular}{c} The compressive strength of the concrete with 50\% \\ RFA and 35\% GGBFS was higher than the standard. \\ The replacement of sand with WFS up to 50\% resulted \\ in water absorption comparable to that of \\ conventional concrete. \\ \end{tabular} \\ \hline [PERSON] et al. [111] & \begin{tabular}{c} Ground Granulated \\ Blast Furnace Slag and \\ Waste Foundry Sand \\ \end{tabular} & Concrete & \begin{tabular}{c} The replacement of up to 15\% of the cement with \\ GGBFS and up to 30\% of the natural sand with WFS \\ improved the mechanical properties of the concrete, \\ such as compressive, flexural, and tensile strength. \\ \end{tabular} \\ \hline [PERSON] et al. [112] & \begin{tabular}{c} Ground Granulated \\ Blast Furnace Slag and \\ Waste Foundry Sand \\ \end{tabular} & Mortars & \begin{tabular}{c} The replacement with 20\% WFS, along with 15\% SF \\ and 15\% GGBFS, resulted in significant improvements \\ in the mechanical properties of the mortars compared \\ to other mixtures. \\ \end{tabular} \\ \hline [PERSON] et al. [113] & \
\begin{tabular}{c} Waste Foundry Sand \\ and Electric Arc \\ Furnace Slag \\ \end{tabular} & Bricks &
\begin{tabular}{c} The combination of 40\% WFS, 30\% FA, and 30\% EAFS \\ produced geopolymer bricks with high strength and \\ lower environmental impact compared to concrete, \\ being classified as non-hazardous. \\ \end{tabular} \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Replacement of aggregates and cement with foundry waste in construction materials. is a wide range of different foundry slags. The increase in cement demand has been effectively addressed through the use of slags, specifically ground granulated blast furnace slag (GGBFS). * Underutilized foundry waste: The incorporation of ceramic mold shells and paraffin waves is less explored in construction materials. Research on their applications is relatively recent and still developing. * Primary application: Among construction materials, concrete is the material most commonly incorporated with foundry waste. * Replacement material: Foundry wastes are used to replace aggregates, cement, or both in construction materials. WFS is commonly used to replace aggregates; on the other hand, the slags and EAFD can replace both aggregates and cement. Ceramic mold shells and paraffin wax can also replace aggregates, and waste mixtures are often used to replace both aggregates and cement simultaneously. * Replacement content: WFS, slags, EAFD, and CMS exhibit a broad range of replacement, varying from 5% up to 100%.