Diabase fine waste for its use in cement-based mortar: Technical remarks, characterization and benefits for the industry

The dimension stone industry generates substantial amounts of moist fine waste during stone processing, raising environmental, economic, and health concerns regarding its accumulation. Addressing the management of this waste is a critical priority. One potential solution is to repurpose stone fine waste as a cost-effective raw material in cement-based mortars. This study focuses on fine waste derived from the diabase transformation process, a medium-grained subvolcanic rock valued for its properties and colour. Despite its potential, diabase fine waste (DFW) remains underexplored as a raw material for mortar production. The authors’ analysis revealed that this industrial waste is more complex than initially understood, containing wood fibres (1 %) and slate rock (20 %). This study offers a characterization of DFW to assess its quality control parameters under practical application conditions. Based on its size distribution and fineness modulus, DFW qualifies as a filler material, with particle shape and texture well-suited for mortar applications. The density of DFW (2964 + 46 kg/m 3 ) is similar to some types of cement, enabling mass-based replacement without altering the mortar’s volume. Additionally, DFW exhibits a higher specific surface area (2.3401 m 2 /g) than some cements but demonstrates lower water absorption than granite fine waste. DFW's mineralogical and chemical properties are compatible with cement formulations, and it exhibits some pozzolanic activity, despite being considered a non-inert mineral admixture. These findings suggest that DFW has significant potential as a filler material in mortar production. However, further research is needed to ensure the homogeneity of DFW for industrial applications. • A new fine waste from the dimension stone sector has been identified for use in mortar. • DFW under contain wood fibres and particles from the slate rock in their composition. • DFW under study can serve as filler to reduce the consumption of cement in mortars. • DFW under study cannot be considered a pozzolan but it is not inert because it has pozzolanic activity. • Factors that may affect its variability, such as the stages and processes where it was generated must be considered.