Effect and durability of sisal fibers in concrete blocks

This work deals with sisal fiber incorporation into concrete blocks during manufacturing in order to evaluate its mechanical properties and increase its durability in cementitious matrixes. For this purpose, 20-mm-long sisal fibers were used at a rate of 1% of concrete volume. For improved sisal durability, a variant requiring a less alkaline matrix and a lower calcium hydroxide formation was chosen. Sisalreinforced blocks were produced using Portland cement PCV ARI RS and using PC 40 RS III cement with 10% in volume of silica, resulting in a less alkaline cementitious matrix. Theses blocks were physically characterized and tested for compressive strength and indirect tensile strength. Additionally, the composite's microstructure was analyzed by scanning electron microscopy and energy dispersive x-ray. Blocks with fibers showed lower compressive strength but higher indirect tensile strength compared with blocks in plain concrete. The sisal fibers exhibited higher durability in the modified cementitious matrix with silica than in the Portland cement ARI cement matrix.