<p>Engineered <?tk 4?>cementitious composites (ECC) are known for their high ductility and for developing numerous fine microcracks that help the material deform without losing integrity. Microcracks smaller than about 100&#xa0;µm generally do not influence durability, but wider cracks can allow aggressive agents to enter the matrix. The use of microencapsulated healing agents has emerged as a promising approach to limit this problem because the capsules can release the healing compound once cracking occurs. In this study, ECC was produced with PVA, PP and PE fibers and with sodium silicate microcapsule dosages of 0%, 4.0%, 4.5% and 5.0% by weight of cement. Durability was evaluated using rapid chloride permeability, sorptivity, low pressure water permeability, carbonation depth and permeable porosity, all under a consistent pre-cracking and healing procedure. The mixtures containing microcapsules showed clear improvement in transport resistance across all fiber systems. Among them, the PVA reinforced ECC with a 4.5% dosage provided the best overall balance of microcrack refinement, activation of the healing agent and improved matrix densification. Statistical analysis confirmed significant differences among the mixtures, and the composite durability index also indicated that 4.5% was the optimal dosage. Taken together, the results demonstrate that the combined use of polymer fibers and microcapsules enhances the self-healing capability of ECC and contributes to improved long-term durability in aggressive environments.</p> Graphical Abstract <p></p>