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This paper presents the experimental data of the behavior of reinforced concrete beams strengthened to shear with carbon fiber composites. The tests were composed of eight T beams, b w =15 cm, h=40 cm, flange width 40 cm, flange height 8 cm, and length 300 cm, divided into two series with the same longitudinal steel reinforcement and a reference beam without strengthening in each series. The beams had two types of arrangement of internal steel stirrups. The test variables were the internal and external geometric ratio of the transverse reinforcement and the mechanical ratio of carbon fiber composites stirrups. All the beams were loaded at two points. The strengthened beams were submitted to a preloading and the strengthening was applied to the cracked beam. All the beams were designed in order to guarantee shear failure, and the ultimate load of the strengthened beams was 36% to 54% greater than the reference beams. The Cracking Sliding Model applied to the strengthened beams was evaluated and showed good agreement with the experimental results.Keywords: shear strengthening; reinforced concrete; external strengthening; carbon fiber composites.Este artigo apresenta os dados de ensaios de vigas de concreto armado reforçadas à força cortante com compósito de fibras de carbono. Os ensaios de oito vigas T, b w =15 cm, h=40 cm, largura da mesa igual a 40 cm, altura da mesa 8 cm, comprimento de 300 cm, divididos em duas séries com a mesma armadura longitudinal e uma viga de referência sem reforço externo para cada série. As vigas tinham dois tipos de arranjos de estribos internos de aço. As variáveis dos ensaios foram as taxas geométricas das armaduras transversais internas e externas, e a taxa mecânica da armadura em estribos de compósito de fibras de carbono. Todas as vigas foram carregadas em dois pontos. As vigas reforçadas foram submetidas a um carregamento prévio e reforçadas após a fissuração. Todas as vigas foram projetadas para garantir a ruptura por força cortante, e as forças últimas das vigas reforçadas foram de 36% a 54% superiores às das vigas de referência. O Modelo da Fissura Deslizante foi avaliado e mostrou boa concordância com os resultados experimentais.Palavras-chave: reforço à força cortante; concreto armado; reforço externo; compósito de fibras de carbono. RC T beams strengthened to shear with carbon

Fulfilment of the thermal properties for newly designed composite materials often requires that the thermal diffusivity in the principal directions is measured. In other instances, the measurement of in-plane diffusivity can give information on transverse defects like imbedded cracks. We present a flash thermography method for simultaneously imaging the through-thickness diffusivity and the in-plane diffusivity of anisotropic materials. It relies upon the use of a grid-like mask between the flash lamp and the inspected materials. Examples are presented for a two sided configuration. It enabled characterising the profile of the principal diffusivities in tensile samples and in carbon disk brakes.

The aim of this work is to develop a reliable and confident non-destructive testing technique by means on infrared thermography. In particular, pulse heating thermography and lock-in thermography as a tool for the evaluation of hidden defect in FRP-reinforced concrete structures were examined. The study on a concrete sample strengthened with externally bonded FRP (Fiber Reinforced Plastic) sheets, with known defects appropriately applied at the FRP-concrete interface, is presented. The results obtained with both procedures are compared.