# Enhanced Eco-Friendly Concrete Nano-Change with Eggshell Powder
\begin{table}
\begin{tabular}{c c} \hline \hline
**The Role of Eggshell in Concrete** & **Source** & **Influence of Eggshell Powder on the Physical and Mechanical Characteristics of Concretes and Mortars** \\ \hline
[4] & Increasing the compressive strength to 20.16 \(\pm\) 4.39 MPa in combination with the addition of nanosilica sol \\ \hline
[12] & Eggshell-derived calcium carbonate improved compressive strength. \\ \hline
[13] & It was found that 10\% eggshell powder as a partial substitute for cement provides a 57\% increase in strength compared to the control composition samples. \\ \hline
[14] & Part of the cement was replaced with 20-50\% fly ash (FA) and 5–10\% eggshell powder (ESP). The optimal percentage of replacement of cement in the concrete mixture for FA was 30–40\%, and for ESP 5\%. The mixtures with 5\% ESP and 30\% FA and with 5\% ESP and 40\% FA showed the highest results compared to other mixtures, 58.9 MPa and 56 MPa—compressive strength results, respectively. \\ \hline
[15] & It has been established that partial replacement of cement with eggshell powder in an amount of 10\% is optimal for fluidity and workability, and 20\% for compressive strength and flexural strength. \\ \hline
[16] & 10\% eggshell powder, when used in mortar, has been tested to provide optimum compressive strength. \\ \hline
[17] & Replacing part of the sand with eggshell powder in an amount of 40\% is the most optimal, as it accelerates carbonization and increases compressive strength. \\ \hline
[18] & Replacing cement with eggshell powder in an amount of 5\% provides a solution with optimal consistency and strength characteristics. However, the water absorption of the solution with eggshell powder is lower compared to the control composition. \\ \hline
[19] & Cement was partially replaced by eggshell powder at 5\%, 10\%, 15\% and 20\%. The compressive strength of the concrete increased by up to 13\%, and the bending strength by up to 11\% at 10\% ESP dosage compared to 0\% ESP dosage. \\ \hline
[20] & Replacement of ESP cement at 5, 10 and 20\% maintained the standard mortar compressive strength. The spent eggshell was subjected to heating up to 450 \({}^{\circ}\)C. Heating up to 450 \({}^{\circ}\)C allows the removal of the organic membrane before crushing and grinding into a powder form without changing the CaCO\({}_{3}\) composition. \\ \hline
[21] & The addition of ESP instead of part of the cement in an amount of 5\% to 10\% leads to an increase in the compressive strength of the concrete. This replacement is most optimal for mixture compositions with a higher water content. \\ \hline
[22] & Obtaining pure CaO by heating eggshells to 900 \({}^{\circ}\)C and replacing part of the cement (5\%, 10\%, 15\%) with it made it possible to obtain new antibacterial composites. \\ \hline \hline \end{tabular}
\end{table} 
Table 2: _Cont._waste by using them in building materials [3; 5; 12; 13; 14; 15; 16; 19; 25; 26; 27; 28; 29; 30; 31; 32; 33; 34; 35; 36; 37; 38; 39; 40]. In addition, there are works related to the improvement of the properties of composite building materials, products, structures, and first, concretes due to their nano-modification [41; 42; 43; 44; 45; 46; 47; 48; 49; 50; 51; 52; 53; 54; 55]. The aim of the work is to fill the scientific gap in the direction of studying the microstructure formation of improved nano-modified environmentally-friendly concrete based on eggshell powder and obtaining a concrete composition for the manufacture of an industrial sample of such a material. Thus, in our study, we aim to combine the concept of \"waste disposal\" with eggshell specification and develop a method of processing to the smallest sizes to achieve the degree of nano-modifying powder for its subsequent use in concrete.