Avaliação técnica da utilização de aditivos biocidas em compósitos cimentícios

Abstract

Although cementitious composites have several applications, they still have limitations in their characteristics, including biodeterioration, due to the action of microorganisms. In order to improve this condition, zinc oxide (ZnO) was added as a biocide additive, in order to add better performance against the action of microorganisms, in addition to pozzolanic materials, rice husk ashes, which, together with the biocide additive, they can improve the mechanical resistance and the absorption of water by capillarity of the cementitious composite. In this study, the properties of cementitious composites with the addition of zinc oxide (ZnO) and rice husk ash (RCA) were evaluated in the fresh and hardened state. Traces were developed, varying the additions, in grams of material, of ZnO at 0%, 5%, 10%, 15% and 20%, in addition to the fixed 10% of CCA, 0.042% of superplasticizer and their w/w ratio. c of 0.5. To evaluate the performance of the cementitious composites, tests were carried out on consistency, resistance to compression and traction in bending, total and partial water absorption by capillarity, in addition to the visual analysis of the biocidal properties. There was great fragility in the samples with the incorporation of the biocide additive, demonstrating a drop in their workability, a reduction in resistance by up to 97% for traction in flexion at 7 days and by up to 98% for compression at 7 days, a water absorption per capillarity three times greater than the reference, as well as a delay in the curing time of the materials. The visual analysis showed little variation in the defined time. [resumo fornecido pelo autor]