Optimizing VO2 integration in cements for the development of thermochromic building materials

Thermochromic vanadium dioxide (VO2) was implemented in opaque cementitious matrices. The impact of three different VO2 types on cement hydration progress was investigated. The leaching behavior of these systems when exposed to water was analyzed and the material’s optical properties were assessed....

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Bibliographic Details
Authors: Galán, Isabel, Lontschar, Katrin, Pérez Álvarez-Quiñones, Gloria, Mittermayr, Florian
Format: article
Status:Published version
Publication Date:2025
Country:España
Institution:Consejo Superior de Investigaciones Científicas (CSIC)
Repository:DIGITAL.CSIC. Repositorio Institucional del CSIC
OAI Identifier:oai:digital.csic.es:10261/397224
Online Access:http://hdl.handle.net/10261/397224
https://api.elsevier.com/content/abstract/scopus_id/105003183917
Access Level:Open access
Keyword:Energy efficiency
Thermochromic properties
Fast setting cement
Reflectance
Building materials
Chemical processes
Description
Summary:Thermochromic vanadium dioxide (VO2) was implemented in opaque cementitious matrices. The impact of three different VO2 types on cement hydration progress was investigated. The leaching behavior of these systems when exposed to water was analyzed and the material’s optical properties were assessed. The presence of VO2 has a retardation effect on the hydration of ordinary Portland cement, less pronounced in the case of tungsten-doped VO2. Additionally, the increased solubility of vanadium oxide in alkaline environments leads to partial loses of vanadium from the matrix during hydration and when exposed to leaching cycles. Tests carried out on fast setting cements in combination with tungsten-doped VO2 showed promising results in terms of VO2 stability within the matrix: (i) the retardation of the hydration process could be shortened, and (ii) < 1 % of the vanadium was lost through leaching. The improved integration of VO2 into the matrix enhanced the material’s thermochromic behavior, represented by a ∼4 % reflectance difference over a temperature interval between 31 and 24 °C. The resulting systems set the basis for the design of intelligent building materials that could be applied to roofs or facades to optimize indoor temperature conditions and thus reduce energy demands in buildings.