# Nanmodified Concrete with Enhanced Characteristics Based on River Snail Shell Powder
## 3 Results  
Table 5 presents the test results of concrete prototypes with the RSSP addition as a partial cement replacement in terms of \"compressive strength\" \(R_{b,cub}\), \"axial compressive strength\" \(R_{b}\), \"flexural tensile strength\" \(R_{bth}\), \"axial tensile strength\" \(R_{btr}\), \"ultimate axial compressive strain\" \(\varepsilon_{b}\), \"ultimate axial tensile strain\" \(\varepsilon_{btr}\), and \"elastic modulus\" \(E\). Figure 4 \"shows the effect of the amount of snail shell powder on the compressive strength of concrete\". The influence of the nano-modifying additive on the mechanical properties of concrete is represented by dependencies based on the saturation function [15]. \[Y(x)=C_{0}+Ax^{b}\sin(\omega x+\varphi) \tag{1}\]  
Here \(Y(x)\) is the mechanical characteristics; \(x\) is the amount of powder in the shells of river snails RSSP, %; \(C_{0}\) is the value of mechanical characteristics without additives; \(b\) is the degree parameter; \(\omega\), \(\varphi\) are parameters of the frequency and phase angle, respectively. Figure 4: Compressive strength of snail shell powder concrete. \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**Composition Number** & \(R_{b,cub}\), \% & \(R_{b}\), \% & \(R_{bth}\), \% & \(R_{btr}\), \% & \(\varepsilon_{b}\), \% & \(\varepsilon_{btr}\), \% & \(E\), GPa \\ \hline
1 & 39.4 & 29.9 & 4.72 & 2.62 & 2.28 & 1.34 & 27.4 \\
2 & 40.6 & 30.3 & 4.84 & 2.68 & 2.24 & 1.32 & 27.8 \\
3 & 42.2 & 31.2 & 4.98 & 2.79 & 2.19 & 1.28 & 28.5 \\
4 & 44.1 & 32.3 & 5.15 & 2.91 & 2.14 & 1.25 & 29.4 \\
5 & 40.2 & 30.1 & 4.81 & 2.66 & 2.27 & 1.34 & 27.7 \\
6 & 36.3 & 27.2 & 4.25 & 2.38 & 2.47 & 1.45 & 25.2 \\
7 & 32.8 & 24.5 & 3.89 & 2.19 & 2.68 & 1.57 & 22.7 \\ \hline \hline \end{tabular}
\end{table} 
Table 5: Strength and deformation characteristics. The physical meaning of the saturation function is as follows. The function reflects two processes: quality improvement and a destructive process of quality reduction if this additive becomes too much. At the first stage, the nano-modifying additive \"leads to an increase in the strength characteristics of concrete\". Then, its effect reaches a maximum and gradually decreases. Figure 4 \"shows that the compressive strength of concrete\" when cement is replaced with snail shell powder in the amount of 6% has a maximum value--12% more than that of the composition without RSSP. At the same time, higher values of compressive strength than the composition without RSSP were observed at dosages of 2, 4 and 8% (from 2 to 7%). From 0 to 6%, the strength increased, while at a dosage of more than 6%, a sharp drop in the strength of concrete was observed (up to 17%). The dependence of the compressive strength of concrete when cement is replaced by snail shell powder was approximated by the function with a coefficient of determination of 0.983. \[R_{b,cub}=39.4+1.277\cdot x^{0.698}\cdot\sin(0.363x);\ \ R^{2}=0.983 \tag{2}\]  
Figure 5 \"shows the effect of the amount of snail shell powder on the axial compressive strength of concrete\". The dependence of the axial compressive strength of concrete on the amount of powder of snail shells RSSP was approximated by the function with a coefficient of determination of 0.991. \[R_{b}=29.9+0.333\cdot x^{1.136}\cdot\sin(0.363x-0.1);\ \ \ \ \ R^{2}=0.991 \tag{3}\]  
Based on the data in Figure 5, the highest axial compressive strength was observed in concrete with a dosage of RSSP of 6-8% more than that of a composition without RSSP. The trend of increase and decrease in strength at other considered dosages of the additive instead of part of the cement is the same as in Figure 4 for compressive strength. The increase in the axial compressive strength at doses of RSSP 2, 4, and 8% ranged from 0.6 to 4.4%, and the decrease in strength at nanomodifier doses of 10 and 12% reached 18%. Figure 6 \"shows the effect of the amount of snail shell powder on the tensile strength in bending of concrete\". Figure 5: Axial compressive strength of snail shell powder concrete.