# Siderurgical Aggregate Cement-Treated Bases and Concrete Using Foundry Sand
## 4 Conclusions  
This work investigated the development of a CTB and SAC aggregate skeleton composed of untreated SA and FS in order to reduce NA consumption and waste production. The physical, mechanical and durability properties of the SAC were characterized and compared with results from another authors. The following conclusions were drawn:  
1. The use of SA and FS for CTB manufacture is feasible, but in order to reach an adequate compression strength (>4.5 MPa) a cement percent higher than 4% needs to be used in order to achieve adequate requirements.
2. A statistical analysis using Minitab software was made to determine the standard deviation of each CTB, which in this case was 0.416 for CTB-A4, 0.650 for CTB-A3 and 0.866 for CTB-A2. In addition, a Pearson correlation test was made to calculate the correlation between cement percent content and UCS. The result of this test was 0.812 and a \(p\)-value of 0.008, which indicates that there is a positive correlation between these variables.
3. The physical properties of the SAC presented high porosity and absorption values. This could be due to the high porosity and absorption of the aggregates used and because this was a low cement content concrete.
4. The mechanical properties of SAC-A and SAC-B presented a moderated compressive strength at 28 days of 27.75 and 38.25 MPa respectively. Modulus of elasticity presented similar values of 33 and 34 GPa, which were similar to results found in the literature. Flexural strength presented higher values than those in conventional concrete and in concrete with up to 50% of FS addition.
5. As to durability properties, total water penetration was occurred in the test specimens. This could be due to the porosity of the SA and the lack of a finer fraction to fill the voids in the concrete matrix. So, in further works, the addition of fillers or a finer FS could be used.
6. In future studies, a comparison between SAC and conventional concrete with NA could be of interest to determine the effects of the use of these RAs on concrete behavior.
7. The findings in this work, and the total water penetration in SAC, suggest that SAC could be used as a layer between soil and structural concrete.  
Conceptualization, J.R. and C.T.; methodology, C.T and G.G.D.A., validation, P.T. and A.A.; formal analysis, G.G.D.A., P.T. and A.A.; investigation, G.G.D.A.; data curation, G.G.D.A.; writing-original draft preparation, G.G.D.A. and A.A.; writing-review and editing C.T., J.R. and G.G.D.A.; visualization, G.G.D.A.; supervision, C.T. and J.R.; project administration, C.T. and J.R. All authors have read and agreed to the published version of the manuscript.  
This research was funded by the company INGECID S.L.  
\begin{table}
\begin{tabular}{c c} \hline \hline
**Mixture** & **Flexural Strength (MPa)** \\ \hline SAC-A & 5.15 \(\pm\) 1.43 \\ SAC-B & 5.88 \(\pm\) 0.17 \\ \hline \hline \end{tabular}
\end{table}
Table 10: Flexural strength of SAC mixtures.  
**Institutional Review Board Statement:** Not applicable.  
**Informed Consent Statement:** Not applicable.  
**Data Availability Statement:** The data presented in this study are openly available.  
**Acknowledgments:** The authors of this research would like to thanks to INGECID S.L. and SIDENOR Reinosa for the steel slags and foundry sand as well to ROCACERO for the for providing the cement and superplasticizer additive.  
**Conflicts of Interest:** The authors declare no conflict of interest.