Assessment of thermal performance of gypsum-based composites with revalorized graphite filler

[Display omitted] •Graphite increases bulk density and λ up to 19% and 97%, respectively.•Specific heat capacity is ranging from 1.01 and 1.22kJ/kg.K.•Emissivity increases between 6.1% and 10.3% with the graphite addition.•Graphite-gypsum board reduces thermal fluxes between 6% and 54%.•Graphite-gypsum boards shows a higher efficiency of the radiant system. European standards place great emphasis on the reintroduction of waste in the production chain. In this research, a combination of experimental tests has been carried out to analyse the use of revalorized isostatic graphite powder waste in gypsum-based boards. A series of gypsum pastes was prepared with a graphite content ranging from 0% to 25%, by weight substitution, and two w/b ratios. Its addition significantly increased the bulk density, thermal conductivity and emissivity of the samples until 19%, 97% and 10%, respectively. Additionally, a reduction of 54% in thermal fluxes towards the outside can be achieved when graphite-gypsum boards replaced gypsum ones at radiative constructive solutions.