# Physical-Mechanical Properties of Cupola Slag Cement Paste
## 2 Materials and Methods
### Cement Comparison  
Table 7 shows a summary of the main properties characterised for both the different cements designed and the mortars manufactured.  
Neither the reference mix nor the two mixes designed will be affected by the presence of sulphates, a guarantee based on the reduced amount of C\({}_{3}\)A provided by the cements. Regarding leachates, a requirement necessitated by a possible application of the mortars for the channelling of drinking water, it has been verified that the raw materials used comply with the requirements defined by the current regulations. Furthermore, in the case of using ground slag to manufacture mortars, as the slag will be encapsulated in the mortar, the risk is even lower. The workability of the mortars was considered as a key parameter for the application studied and, therefore, the _w/c_ ratio was set to ensure that the workability of the three mortars was equal.  
It was found that the presence of CSF increases both the start and end setting times. It was found that with 80% CEM I + 20% CSF cement the setting time is similar to that of the cement currently used for this application. However, in the case of using a 50% CEM I + 50% CSF cement, the setting time increased significantly, but this increase in the setting time could be corrected by means of a setting activator.  
\begin{table}
\begin{tabular}{c c c c} \hline \hline
**Property** & **CEM III** & **80\% CEM I + 20\% CSF** & **50\% CEM I + 50\% CSF** \\ \hline Sulphur resistant & Yes & Yes & Yes \\ Leached problems & No & No & No \\ Setting time & Currently used & Similar to reference & Larger, but compensable \\ Workability & Currently used & Similar to reference & Similar to reference \\ Mechanical properties & Currently used & Higher to reference & Slightly lower than reference \\ \hline \hline \end{tabular}
\end{table}
Table 7: Comparison of the properties of the different cements and mortars.  
Finally, in relation to the mechanical properties of the three mortars, it can be seen that when the mortars made with the 50% CEM I + 50% CSF cement and the reference cement (CEM III) are compared, they give rise to similar mechanical properties, while the mortars with 80% CEM I + 20% CSF cement have superior mechanical properties.  
Based on the above comments, it can be concluded that 80% CEM I + 20% CSF cement would be suitable to replace the currently used CEM III, as in all aspects it provides similar or superior properties. In order to use 50% CEM I + 50% CSF cement, it would be necessary to first ensure: (i) The loss of mechanical properties is acceptable; (ii) to evaluate whether it is necessary to use a setting accelerator.  
As a general consideration, the use of these slags as substitutes for cements, and the main motivation for the work, not only represents a notable carbon footprint associated with cement, but also involves the elimination of a waste that is being taken to landfills. From the economic point of view, the company generating the waste will benefit from savings in landfill rates (which have also been increasing in recent years) for thousands of tons per year. The contribution of these slags to the carbon footprint of cement may not be very high since the rates of cement consumption far exceed the volumes of waste generation. This should be good news because it guarantees that all the generated waste could have an application.