Future perspectives to improve the energy efficiency of concentrating solar power (CSP) plants are focused on increasing temperatures above 600 ◦C. Among the different components of a CSP plant, the thermal energy storage (TES) medium must withstand high operating temperatures. Concrete was identified as an exciting candidate for its mechanical and thermal properties, needing further experimental research about this specific application. A fundamental concrete element is the cement binder, bringing cohesion to the composite components. As a requisite, the cement needs to be heat-resistant, and calcium aluminate cement (CAC) suits this demand. This cement is characterised by curing temperature-driven crystallisation changes, triggering an alteration of material properties. Considering that at 60 ◦C, the metastable hexagonal crystallisation is converted into a stable cubic crystallisation, seven curing cases were proposed in this study. After the curing process, thermo-mechanical properties of calcium aluminate cement paste were tested before and after thermal cycles from 290 ◦C to 650 ◦C. The results showed that, despite thermal cycling, the immediate hydration at 60 ◦C results in a higher thermal conductivity and compressive strength than standard curing at 20 ◦C.
novaci´on - Agencia Estatal de Investigaci´on (PID2021-123511OB-C31
- MCIN/AEI/10.13039/501100011033) and by the Ministerio de Ciencia,
Innovaci´on y Universidades - Agencia Estatal de Investigaci´on (AEI)
(RED2018-102431-T). The authors at University of Lleida would like to
thank the Catalan Government for the quality accreditation given to
their research group (2017 SGR 1537). GREiA is a certified agent TECNIO
in the category of technology developers from the Government of
Catalonia. This work is partially supported by ICREA under the ICREA
Academia programme. Laura Boquera acknowledgments are due to the
PhD school in Energy and Sustainable Development from University of
Perugia. Laura Boquera would like to acknowledge the financial support
provided by UNIPG –CIRIAF InpathTES project. The authors also thank
Ciments Molins industrial that provided the material to make possible
this experimental research. Financial support of the UNIPG-CIRIAF team
has been achieved from the Italian Ministry of University and Research
(MUR) in the framework of the Project FISR 2019 “Eco Earth” (code
00245) that is gratefully acknowledged.