## 5 Conclusions  
The present work aimed at studying the effects of cement prehydration due to uncontrolled storage from a phenomenological point of view through the application of the EMM-ARM method for the characterization of the early-age evolution of the elastic modulus of cement pastes. Attention has been focused on Portland (CEM II/A) as well as pozzolanic (CEM IV/B) cement; the latter has never been investigated by EMM-ARM. In addition to storage time, which was assumed as the control variable for prehydration, specific tests have also been carried out to assess the influence of curing temperature on the early age evolution of the Young's modulus of pozzolanic cement pastes. A total of eight experiments were conducted, six of which were on CEM II/A and CEM IV/B specimens stored for different periods of time up to one year, and the remaining two on CEM IV/B specimens cured at two different temperatures typical of environmental Mediterranean scenarios. Based on the obtained results, the following conclusions can be drawn:  
* The material stored in uncontrolled conditions undergoes phenomena that have negative effects on both Young's modulus and hardening rate as storage time increases. The observed trend was very marked for CEM II/A, characterized by higher clinker presence, with a reduction in the elastic modulus after 240 days of storage equal to 38% at 120 h since casting. The pozzolanic cement (CEM IV/B) proved to be less sensitive to the phenomenon of prehydration, with an 18.7% reduction in the elastic modulus observed at 120 h since casting on specimens produced from cement stored for one year; nevertheless, the effect cannot be neglected;  
Figure 7: Elastic modulus vs. time for CEM IV/B cement paste at 15 \({}^{\circ}\)C and 20 \({}^{\circ}\)C.  
a reduction in curing temperature of 5 \({}^{\circ}\)C with respect to the reference ordinary value of 20 \({}^{\circ}\)C induces a delay in the [PERSON]'s modulus evolution of pozzolanic cement paste, with a 25% reduction in E at 120 h since casting. In summary, the present study confirms that the EMM-ARM method can be used to assess the possible effect of cement prehydration based on a phenomenological approach. Considering that prehydration due to uncontrolled storage significantly affects the early-age evolution of the [PERSON]'s modulus of the cement paste, the present study demonstrates the applicability of EMM-ARM for the phenomenological characterization of the effect of uncontrolled storage and, therefore, prehydration on the mechanical properties of cement paste, with particular attention to pozzolanic as well as Portland cement. In this framework, a further applicative perspective of the EMM-ARM technique might be its application as an additional experimental test in the context of the CE marking qualification procedure of cement-based materials [38], with specific reference to the verification of constancy of performance. Thus, it might be attractive for acceptance checks of cementitious materials before use or commercialization. Conceptualization, C.R. ; methodology, L.C., P.C. and C.R. ; software, L.C. ; validation, P.C. and C.R. ; formal analysis, L.C., P.C. and C.R. ; investigation, L.C. ; resources, G.F., A.O. and C.R. ; data curation, L.C. and P.C. ; writing--original draft preparation, L.C., P.C. and C.R. ; writing--review and editing, G.F., A.O. and C.R. ; visualization, L.C. and P.C. ; supervision, G.F., A.O. and C.R. ; project administration, G.F. and C.R. ; funding acquisition, C.R. All authors have read and agreed to the published version of the manuscript. The present study has been carried out in the framework of the PRIN 2017 \"SURMOUNT--Innovative Systems for the UpgRade of MasOnry structUres and Non sTructural elements\" research project (funded by the Italian Ministry of University and Research under grant No. 20173 SJJJJ8), whose financial support is gratefully acknowledged. Not applicable. The data that support the findings of this study are contained within the article.