Avaliação da durabilidade dos concretos fornecidos por centrais dosadoras

• Autor(a) principal: Paula, Marcelo Cândido de
• Data de Publicação: 2018
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Repositório Institucional da UFG
• Texto Completo: http://repositorio.bc.ufg.br/tede/handle/tede/11743
• topic: Concreto; Centrais dosadoras; Durabilidade; Curva de Abrams; Carbonatação; Migração de cloretos; Concrete; Metering stations; Durability; Abrams curve; Carbonation; Migration of chlorides; ENGENHARIAS::ENGENHARIA CIVIL::CONSTRUCAO CIVIL

This research aimed to evaluate the mechanical behavior and durability of concrete supplied by premixed concrete batching plants with the strength classes most used by the main construction companies in the region of Goiânia/GO (C25, C30, C35, C40 and C45, being conventional pumped concrete with maximum dimension characteristic of coarse aggregate of 19 mm and consistency class S50, slump 50 ≤ to < 100 mm). The durability parameters used were obtained through accelerated and natural carbonation, chloride migration, total absorption, capillary absorption, water permeability, electrical resistivity and ultrasound tests. In terms of mechanical properties, compressive strength and modulus of elasticity were the studied parameters. Finally, the impact on the durability of the concrete produced by the increase in the water/binder ratio was evaluated, considering the environment in which the structural element is inserted, as well as the effect of different constituent materials present in each concrete (in this context of durability). Based on the results obtained, it was found that a significant part of the concrete does not comply with the maximum water/cement ratio recommendations of ABNT NBR 6118: 2014, and its values are, in many cases, much higher. This causes an important drop in the performance regarding the carbonation of concrete, which will certainly result in a reduction in the useful life of the concrete structure and in non-compliance with the current minimum VUP requirements of 50 years for the structural system (according to ABNT NBR 15575: 2013). As for chlorides, there is an important influence of the water/binder ratio, but the effects resulting from the type of cement used were very significant in the results. In this regard, an important contribution of mineral additions in reducing the transport of chlorides in concrete was found.