# Evaluation of Early-Age Compressive Strength in Winter Prefabrication: A Comparative Study
## 4 Results and Discussion
### Calorimetric Test  
Merging the findings of Figures 3-5 and Table 10, we obtain a cohesive overview of the impact of environmental conditions and cement type on hydration kinetics and mechanical performance across three scenarios: standard ambient curing, cold storage with warm mixing water, and post-mixing heat treatment. \begin{table}
\begin{tabular}{c c c c c} \hline \hline  & & \multicolumn{3}{c}{**Scenario 1**} \\ \cline{3-5}
**Compressive Strength [MPa]** & & & **T = 20 \({}^{\circ}\)C** & \\ \cline{2-5}  & & **Fi-1** & **Fii-1** & **Fiii-1** \\ \hline
24 h & 32.3 & 31.8 & 24.3 \\ \hline
7 days & 55.9 & 54.3 & 46.9 \\ \hline
28 days & 62.9 & 65.8 & 56.1 \\ \hline \hline \end{tabular}
\end{table} 
Table 8: Early-age and long-term compressive strength of cement formulations under standard conditions (20 \({}^{\circ}\)C) in scenario 1. \begin{table}
\begin{tabular}{c c c c c c c c c c} \hline \hline  & & \multicolumn{6}{c}{**Scenario 2**} & \multicolumn{6}{c}{**Scenario 3**} \\  & & **Scenario 1** & & & **Material 8 \({}^{\circ}\)C** & & & **Material 8 \({}^{\circ}\)C** \\  & & **T = 20 \({}^{\circ}\)C** & & & **Water Heated 35 \({}^{\circ}\)C** & & & **Heat 35 \({}^{\circ}\)C** & \\ \cline{2-5}  & & & & & **Storage 8 \({}^{\circ}\)C** & & & & **Heat 35 \({}^{\circ}\)C** & \\ \cline{2-5}  & **Fi-1** & **Fii-1** & **Fii-1** & **Fi-2** & **Fii-2** & **Fii-2** & **Fii-3** & **Fii-3** & **Fii-3** \\ \hline Compressive strength [MPa] 24 h & 32.3 \(\pm\) 1 & 31.8 \(\pm\) 0.5 & 24.3 \(\pm\) 0.7 & 7.7 \(\pm\) 0.2 & 9.3 \(\pm\) 0.5 & 3.2 \(\pm\) 0.2 & 38.3 \(\pm\) 1 & 39.8 \(\pm\) 1.5 & 30.9 \(\pm\) 0.7 \\ \hline \hline \end{tabular}
\end{table} 
Table 9: Comparative analysis of compressive strength across different formulations and conditions. Figure 4: Calorimetric analysis of hydration in fi-2 cement: cold storage conditions. Figure 3: Calorimetric analysis of hydration in fi-1 cement: standard curing conditions. * Scenario 1: Standard ambient curing  
Fi-1: Exhibits a sharp rise in temperature and heat released, indicative of rapid hydration kinetics, primarily due to the high reactivity of CEM I 52.2N. The early peak in temperature followed by a sustained heat release suggests an aggressive exothermic reaction typical of high-grade Portland cement. The calorimetric data reveal the highest heat release at 328 J/g, corresponding with a significant early-age compressive strength of 32.3 MPa. Fii-1 and Fiii-1: Show moderated calorimetric profiles due to the inclusion of SCMs (Supplementary Cemerentitious Materials), with heat releases of 325 J/g and 241 J/g, respectively. This moderation is reflected in the slightly adjusted strength values of 31.8 MPa and 24.3 MPa, indicating the SCMs' effectiveness in tailoring the hydration kinetics and strength development path. * Scenario 2: Cold Storage with warm mixing water  
Fi-2: The rise in temperature is less marked, and the increase in heat released is more gradual, with a significant reduction in the heat released at 210 J/g due to cold storage conditions. This scenario highlights a delayed and prolonged dormant phase of hydration, leading to a markedly lower compressive strength of 7.7 MPa. Fii-2 and Fiii-2: Reflect slightly higher total heat releases (215J/g and 82J/g, respectively) than Fi-2, showing the mitigating effect of SCMs on cold cure conditions. The resultant compressive strengths of 9.3 MPa and 3.2 MPa provide insight into the complex interactions between cement hydration and SCM reactivity under adverse temperature conditions.