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Structural masonry using concrete blocks promotes the rationalization of construction projects, lowering the final cost of a building through the elimination of forms and the reduction of the consumption of reinforcement bars. Moreover, production of a block containing a combination of concrete and vegetable fiber sisal results in a unit with properties such as mechanical strength, stiffness, flexibility, ability to absorb energy, and post-cracking behavior that are comparable to those of a block produced with plain concrete. Herein are reported the results of a study on the post-cracking behavior of blocks, prisms, and small walls reinforced with sisal fibers (lengths of 20 mm and 40 mm) added at volume fractions of 0.5% and 1%. Tests were performed to characterize the fibers and blocks and to determine the compressive strength of the units, prisms, and small walls. The deformation modulus of the elements was calculated and the stress-strain curves were plotted to gain a better understanding of the values obtained. The compression test results for the small walls reinforced with fibers were similar to those of the reference walls and better than the blocks and prisms with added fibers, which had resistances lower than those of the corresponding conventional materials. All elements prepared with the addition of sisal exhibited an increase in the deformation capacity (conferred by the fibers), which was observed in the stress-strain curves. The failure mode of the reference elements was characterized by an abrupt fracture, whereas the reinforced elements underwent ductile breakage. This result was because of the presence of the fibers, which remained attached to the faces of the cracks via adhesion to the cement matrix, thus preventing loss of continuity in the material. Therefore, the cement/plant fiber composites are advantageous in terms of their ductility and ability to resist further damage after cracking.Keywords: vegetable fiber, post-cracking behavior, structural masonry.A alvenaria estrutural com blocos de concreto promove a racionalização da construção, com redução do custo final da edificação, por meio da eliminação de fôrmas e da redução do consumo de armaduras. Além disso, produzir um bloco com a combinação de concreto e fibra vegetal de sisal resulta em uma unidade que apresenta características mais apropriadas de resistência mecânica, rigidez, ductilidade, capacidade de absorção de energia e comportamento pós-fissuração, em comparação com o bloco produzido com o concreto simples. O presente trabalho avalia o comportamento pós-fissuração de blocos, prismas e pequenas paredes de concreto reforçado com fibra de sisal de comprimento 20 e 40 mm, e fração volumétrica de 0,5 e 1%. Foram realizados os testes de caracterização da fibra e do bloco, e os ensaios de resistência à compressão axial das unidades, dos prismas e das pequenas paredes. O módulo de deformação dos elementos foi calculado e foram traçados os diagramas tensão-deformação para uma melhor interpretação dos valores obtidos. Os resultados do e...