Civil construction is one of the most resource-consuming sectors in the world. For this reason, the last years have witnessed the study of reusing industrial residues in building materials. The ornamental stone processing industry has a considerable environmental liability related to residue generation during the cutting stages of granite blocks. The objective of this work is to analyze the viability of incorporating granite residues, up to 100%, to substitute sand in coating mortars for building construction. Mortars without residue, as control, and incorporated with 20, 40, 60, 80, and 100% of granite residue were subjected to consistency tests, incorporated air and water retention together with the rheological characterization using the squeeze-flow and the dropping-ball methods. The results show that mortars with 40% granite residues presented greater plastic deformation, helping their applicability by also presenting improved technological properties in the fresh state.

This study investigates the potential use of Casuarina equisetifolia cone bottom ash (CC-BA) as an additional material in rendering mortars for wall and ceiling applications. A bibliometric analysis revealed a significant lack of research on the topic. Casuarina cones, widely dispersed in urban areas, pose a public maintenance burden but can be used as fuel, producing ash with potential applications in construction. Mortars were prepared with a 1:6 cement-to-sand ratio, incorporating 5 to 25% CC-BA by weight relative to the mass of cement, in addition to a reference mix (CPII-00). The materials underwent physical, chemical, and microstructural characterizations. Fresh-state testing indicated satisfactory workability up to 15% CC-BA, with CPII-10 yielding the best results. All compositions met the consistency index requirements, although water demand increased with higher CC-BA content. Calorimetry results highlighted CPII-05 and CPII-15 as thermally satisfactory, indicating accelerated hydration kinetics. Air content decreased with CC-BA addition, suggesting a filler effect. After 28 days, mechanical strength remained favorable up to CPII-15. Water absorption and void index increased with 20–25% CC-BA, while lower contents showed comparable or improved values relative to CPII-00. Microstructural analysis, particularly via micro-computed tomography (μ-CT), confirmed the filler effects of CC-BA, enhancing performance up to CPII-15. Overall, CPII-10 demonstrated the most promising balance of properties, with CPII-15 also suitable for the proposed applications.