The fiber‐reinforced self‐compacting concrete (FR‐SCC) is considered a high‐performance material, clustering characteristics of SCC combined with steel fibers. This paper assessed fresh and hardened state properties of a reference SCC and a FR‐SCC with fibers of three types and three quantities of reinforcement, totalizing 10 mixtures. Fresh state properties of the mixture were evaluated through the tests of slump‐flow, flow rate, filling ability, plastic viscosity by V‐funnel, passing ability by J‐ring and by L‐box; and hardened properties comprised compressive strength, flexural strength, and flexural toughness. Overall, it was observed that increasing the amount and length of fibers hindered the mixture workability. Also, the flexural strength and flexural toughness increased as the length and the amount of fibers increased. Regarding mechanical properties, it was not possible to identify an equivalence between the types of fibers evaluated and the compressive strength of mixtures. The flexural was proportional to the amount of fibers, with increases of up to 30% for concretes with fibers.
One of the factors that affect the concrete structures durability is the corrosion in reinforcement steel. This phenomenon does not occur because of the physical and chemical protection that concrete offers. Among the factors that cause the degradation of reinforced concrete, the ingress of chloride ions stands out. This phenomenon reproduction in laboratory is difficult because of its time for natural occurrence. Therefore, researchers created tests that accelerate the ingress of ions inside concrete in order to simulate how this process will occur in real situations. The Salt Spray test, showed by ASTM B117 standard, is one of these tests, which has been widely utilized in the analysis of metal materials, but it is rare in concrete. Thus, this paper aims to evaluate the chloride ions attack behavior on the four concrete mixes showed by ABNT NBR 6118. The samples are prismatic and the ions attack geometry was observed through the longitudinal rupture of the samples, silver nitrate chemical indicator aspersion and image analysis using the softwares, AutoCAD and Arc Map 10.3. The samples with and without protection in its ends and two different sizes were utilized. On samples without protection, the combined effect of the ingress by the end and the sides of the samples was observed, adding to its influence on maximum penetration of the chloride ions. The maximum penetrations increased to twice in the analysis by longitudinal rupture, compared to the analysis by the transversal rupture in four heights, because of the heterogeneous profile showed in samples.
Visando propiciar aos usuários de imóveis o melhor conforto acústico, o mercado da construção civil tem-se baseado nos critérios de desempenho prescritos pela NBR 15575 (ABNT, 2013), os quais indicam a verificação dos sistemas e de produtos dentro de parâmetros mínimos de desempenho. Por meio da norma, há o esclarecimento dos requisitos impostos pela mesma, sendo esses analisados com base na segurança e da habitabilidade das edificações, bem como durabilidade de sistemas. Dentre as áreas analisadas por essa norma, há o desempenho acústico, o qual não apresenta, de forma abrangente, a caracterização dos sistemas construtivos utilizados em todo país. Desta forma, este estudo tem o objetivo de avaliar o isolamento acústico em laboratório de diferentes sistemas de vedação vertical, compostos por alvenaria de blocos cerâmicos, a partir da inserção de revestimento em blocos de dimensão 14x19x59 cm e de preenchimento dos vazios e adição de revestimento em blocos de dimensão 19x19x39 cm. O revestimento testado foi a argamassa e o preenchimento dos vazios foi feito com vermiculita expandida. As verificações foram feitas em ambiente laboratorial, sendo executados de acordo com a ISO 10140-2:2010. Os resultados obtidos apontaram uma melhora no desempenho dos sistemas, sendo elucidados nos blocos de dimensão 14x19x59 cm, através do revestimento argamassado, o qual resultou num acréscimo de 11dB no índice de redução sonora ponderado e para o revestimento argamassado e preenchimento de vazios, com vermiculita expandida nos blocos de dimensão 19x19x39 cm, o qual apresentou um acréscimo de 2 dB. Palavras-chave: sistema vertical de vedação, diferentes revestimentos, vermiculita.
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