Effect of Peruvian sisal fiber on the mechanical and microstructural strength of concrete

In response to environmental concerns, such as global warming, there has been growing interest in the development of sisal fiber (SF)-reinforced concrete due to its low environmental impact and reduced cost. This study evaluated the effect of SF on the mechanical and microstructural properties of concrete. Sisal fibers, with a length of 50 mm, were selected and added to concrete at 0.5, 1, 1.5, 1.5, and 2% by weight of cement, with a treatment using CaO for 7 days. A total of 80 specimens were prepared to analyze compressive strength, tensile strength, flexural strength, elastic modulus, and microstructural properties. The results showed that the optimum SF content was 1.5%, where parameters such as workability, unit weight, and air content decreased but remained within permissible ranges, while temperature remained constant. Significant improvements were observed in compressive, tensile, and flexural strengths, with increases of 17.80%, 52.30%, and 88.83%, respectively. However, a 5.56% reduction was observed in the elastic modulus compared to the reference concrete. X-ray diffraction analysis revealed changes in the concentrations of crystalline phases such as quartz and albite, while energy dispersive spectroscopy highlighted a higher oxygen content, indicating more efficient hydration of the cement. The 1.5% SF (T4) optimizes cost–benefit (+ 88.8%), but higher doses reduce efficiency. It is ideal for walls and sidewalks, prioritizing resistance to cracking and sustainability. SF is eco-efficient and economical compared to synthetic fibers. This demonstrates that the incorporation of SF into concrete represents a sustainable and efficient alternative that significantly improves its mechanical and microstructural properties.