In comparison with a vibrated concrete (VC) of the same strength class, self‐compacting concrete (SCC) typically has a lower coarse aggregate content and, possibly, a smaller maximum aggregate size. This may result in reduced aggregate interlock between the fracture surfaces of a SCC. Since aggregate interlock plays an important role in the shear strength of slender beams, SCC beams may have a shear strength lower than that of similar VC beams, but studies on that subject are still limited. This article summarizes an experimental programme that includes beams of high‐strength SCC and transverse reinforcement ratios around the minimum given by different codes – a case that had not been investigated so far. The shear strengths of those SCC beams are compared with those of VC beams with similar concrete compressive strength and small ratios of transverse reinforcement and also compared with beams calculated according to different code procedures.

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ResumoIn comparison with vibrated concrete (VC) of the same strength class, self-compacting concrete (SCC) typically has a lower coarse aggregate content and, eventually, a smaller maximum aggregate size. This may reduce the aggregate interlock between the fracture surfaces in SCC. Since the aggregate interlock plays an important role in the shear strength of slender beams, SCC beams may have a shear strength lower than that of similar VC beams. This article summarizes experimental studies on the shear strength of reinforced SCC slender beams without and with shear reinforcement. The shear strengths of SCC beams are compared with the ones of VC beams and also to the calculated ones according to different code procedures. It is shown that powder-type SCC beams tend to have lower shear strength than similar VC beams and that the difference depends upon the concretes composition and the characteristics of the beams.Keywords: self-compacting concrete, slender beams, shear strength.Em comparação com o concreto vibrado (CV) de mesma classe de resistência, o concreto autoadensável (CAA) tipicamente apresenta menor quantidade de agregado graúdo e, eventualmente, menor dimensão máxima deste agregado. Isto pode reduzir o engrenamento de agregados entre as superfícies de ruptura do CAA. Sendo o engrenamento dos agregados um parâmetro de influência importante na resistência à força cortante de vigas esbeltas, as vigas de CAA podem ter resistência à força cortante menor que a de vigas similares de CV. Este artigo resume estudos experimentais sobre a resistência à força cortante de vigas esbeltas de CAA sem e com armadura de cisalhamento. As resistências à força cortante de vigas de CAA são comparadas com as de vigas de CV e também com as calculadas segundo procedimentos de diferentes normas. É mostrado que as vigas de CAA com menor teor de agregados graúdos tendem a ter menor resistência à força cortante que vigas semelhantes de CV e que a diferença depende da composição dos concretos e das características das vigas.Palavras-chave: concreto autoadensável, vigas esbeltas, resistência à força cortante.

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This paper aims to contribute to a more rational understanding of the shear strength behavior of steel fiber‐reinforced concrete beams without stirrups. For this purpose, an experimental program comprising eight slender beams varying the fiber content and type, tested in three‐point bending configuration with a complete monitoring of the displacement fields of the failure span, was carried out. A detailed analysis of the shape and kinematics of the critical crack, associated with the investigation of the shear transfer mechanisms during the test given by mechanical models available in the literature, was performed. The theoretical–experimental analyzes proved to be a promising approach for quantifying the contribution of each relevant parameter to the shear capacity, such as the fiber concrete residual tensile response. The study, therefore, presents a contribution toward a rational and comprehensive methodology for the shear design of concrete members. The influence of shape and kinematics of the critical crack on the shear response is also reported and a theoretical explanation is provided to justify the fact that beams with the same characteristics have different cracking patterns but similar shear strength.

AgradecimentosA Deus, por ter me dado a oportunidade de desenvolver este estudo na Pontifícia Universidade Católica do Rio de Janeiro (PUC-Rio), onde tive o prazer de conviver e trabalhar com profissionais competentes e atenciosos.Aos meus pais e irmão, por acreditarem neste projeto e terem me dado total apoio em minha jornada estudantil.À Iandra Galdino, fonte de inspiração, pelo companheirismo e incentivo na condução deste curso.À Universidade Federal dos Vales do Jequitinhonha e Mucuri (UFVJM), por me permitir dedicação exclusiva a este estudo. Especiais agradecimentos aos colegas do Instituto de Ciência, Engenharia e Tecnologia (ICET/UFVJM), por suprir minha ausência neste período.Às universidades onde cursei a graduação e mestrado em Engenharia Civil,

Shear strength in reinforced concrete (RC) beams, especially in steel fiber reinforced concrete (SFRC) beams is a subject of great interest in structural engineering. In the case of beams without transverse reinforcement, the failure is explained based on a predefined crack pattern and kinematics, and the transfer of shear force accomplished through different mechanisms. Among these mechanisms, the aggregate interlock is present in most of the existing shear strength mechanical models in the literature, with divergences regarding its performance and preponderance. Thus, this paper focuses on evaluating the contribution of aggregate interlock throughout the critical crack formation process up to the ultimate load by performing bending tests on small-scale rectangular RC and SFRC beams without considering the effect of transverse reinforcement. The Digital Image Correlation (DIC) technique is used to track the patterns of shear cracks and their associated kinematics by measuring the relative displacements of opening (w) and sliding (δ). A detailed description of the shear behavior of these beams is provided by quantifying the aggregate interlock using the simplified Walraven model. The results help to understand the level of contribution of the aggregate interlock, and the main differences between structural elements of concrete with and without steel fibers in the scope of the shear strength.