Influência dos resíduos de rochas ornamentais de diferentes naturezas empregados como adição mineral nas propriedades de argamassas estruturais

Abstract

Brazil stands out as one of the world’s leading powers in the export and processing of ornamental stones; however, between 20 and 30% of this production is converted into waste. When incorporated into cementitious matrices, these wastes can act as fillers. Within this context, this study aimed to evaluate the individual performance of three waste derived from the sedimentation sludge of ornamental stone processing of different natures (granite, marble and São Tomé stone) when used as a mineral addition in structural mortars. The wastes were properly characterized, and the mortars were assessed in terms of their physical, mechanical and durability properties. The results indicated that the incorporation of ornamental stone waste led to improvements in most of the parameters evaluated. Open porosity was reduced by 29.7%, 28.0% and 21.2% in mortars containing São Tomé stone, marble and granite waste, respectively, compared to the reference mortar. Capillary water absorption showed more pronounced reductions of 37.0% and 22.7% in mortars with São Tomé stone and marble wastes. Similarly, total water absorption was significantly reduced, with decreases of 31% for São Tomé stone, 30% for marble and 22% for granite. The carbonation depth of mortars containing ornamental stone wastes was markedly low, with values below 0.4 mm. Regarding chloride penetration, improvements of 35.5% were observed in mortars with marble waste, 44.9% in those with granite waste and 47.7% in those with São Tomé stone waste. Compressive strength at 98 days was similar for all mortars, with values close to 70 MPa, as was flexural strength at 98 days, which reached approximately 8 MPa. It is concluded that the origin of the waste significantly influences the performance of structural mortars when used as a mineral addition, with a greater impact on physical and durability-related properties. Emphasis is given to the São Tomé stone waste, which is still scarcely explored in the scientific literature and presented the best overall results.