Near surface mounted (NSM) strengthening technique using carbon fibre reinforced polymer (CFRP) laminate strips was applied for doubling the load carrying capacity of concrete beams failing in bending. This objective was attained and the deformational capacity of the strengthened beams was similar to the corresponding reference beams. The NSM technique has provided a significant increment of the load at serviceability limit state, as well as, the stiffness after concrete cracking. The maximum strain in the CFRP laminates has attained values between 62% and 91% of its ultimate strain. A numerical strategy was developed to simulate the deformational behaviour of RC beams strengthened by NSM technique. Not only the load carrying capacity of the tested beams was well predicted, but also the corresponding deflection.

Near Surface Mounted (NSM) is a recent strengthening technique based on bonding Carbon Fiber Reinforced Polymer (CFRP) bars (rods or laminate strips) into pre-cut grooves on the concrete cover of the elements to strength. To assess the effectiveness of the NSM technique, an experimental program is carried out involving reinforced concrete (RC) columns, RC beams and masonry panels. In columns failing in bending the present work shows that the failure strain of the (CFRP) laminates can be attained using the NSM technique. Beams failing in bending are also strengthened with CFRP laminates in order to double their load carrying capacity. This goal was attained and maximum strain levels of about 90% of the CFRP failure strain were recorded in this composite material, revealing that the NSM technique is also very effective to increase the flexural resistance of RC beams.The effectiveness of externally bonded reinforcing (EBR) and NSM techniques to increase the flexural resistance of masonry panels is also assessed. In the EBR technique the CFRP laminates are externally bonded to the concrete joints of the panel, while in the NSM technique the CFRP laminates are fixed into precut slits on the panel concrete joints. The NSM technique provided a higher increase on the panel load carrying capacity, as well as, a larger deflection at the failure of the panel.The performance of EBR and NSM techniques for the strengthening of RC beams failing in shear is also analyzed. The NMS technique was much more effective in terms of increasing the beam load carrying capacity, as well as, the beam deformability at its failure. The NSM technique was easier and faster to apply than the EBR technique.

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A adição de fibras no concreto vem se mostrando uma ferramenta eficaz para o melhoramento do desempenho e da durabilidade de elementos estruturais nas edificações. O objetivo deste trabalho foi realizar um estudo sobre a utilização de fibras não metálicas no concreto, identificando os tipos mais utilizados e as áreas de aplicação. Para isso, foi realizada prospecção tecnológica por meio de uma pesquisa exploratória com uma abordagem quantitativa e qualitativa, apoiando-se nos resultados das publicações científicas da CAPES e Web of Science, e patentárias do INPI e Orbit. A prospecção apontou um crescimento do estudo da temática nos últimos dez anos, havendo uma liderança na utilização das fibras sintética, seguido pelas fibras poliméricas e em terceiro as fibras vegetais, sendo que, o concreto com a adição de fibras, vem sendo utilizado principalmente nas áreas em que a agressividade ambiental, a abrasão e os esforções de tração são determinantes para a estabilidade estrutural.