Metakaolin composite with graphite powder: Material characterization for self-heating potential evaluation.

Self-heating construction materials are of high potential within the design of de-icing and snow-melting systems used in constructions, roads, or pavements. In the past, mainly cementitious materials were subjected to the research of the design/optimization of self-heating mixtures using a wide range of electrically conductive admixtures, an appropriate determination of electrical properties, and electrode embedment/attachment. Taking into consideration the negative environmental impact of the production of cementitious materials, alkali-activated cementless composites are promising substituents that can be doped by electrically conductive admixtures to gain new functional properties, such as self-heating. The paper is focused on the design of alkali-activated metakaolin composite with 8 wt.% of graphite powder and experimental determination of basic physical and electrical properties to make a preliminary assessment of appropriateness for self-heating construction applications. The compressive strength, volt-ampere characteristic, DC electrical conductivity, as well as AC electrical characteristics were determined to assess the self-heating potential of the composite. The DC/AC electrical properties of the composite were promising in terms of self-heating function (σ = 3.01 × 10⁻¹ S·m⁻¹) at a reasonable level of mechanical properties for some construction applications (R_c = 10.5 MPa, R_f = 1.2 MPa). [ABSTRACT FROM AUTHOR]