Mechanical Properties of Natural Jute Fiber-Reinforced Geopolymer Concrete: Effects of Various Lengths and Volume Fractions

Enhancing the fracture strength and ductility of concrete through the incorporation of various types of synthetic and natural fibers with varying textures and contents remains challenging. Natural fibers, being versatile and eco-friendly construction materials, can be an excellent alternative to synthetic fibers. However, studies on natural fiber-reinforced (especially through the incorporation of jute fibers) novel composites like geopolymer binders remain deficient. Thus, the effects of various lengths (15, 25 and 35 mm) and volume contents (0.10, 0.20, 0.30, 0.40, 0.50, 0.60, and 0.70%) of natural jute fibers on the mechanical performance of fiber-reinforced geopolymer concrete were studied. The results revealed that jute fiber reinforcement remarkably affected the workability, compressive strength, fracture strengths, water absorption and microstructure properties of the proposed geopolymer concretes. Increasing the fiber length and volume fractions in the geopolymer matrix lowered the slump values and workability and increased the compressive strength. The specimen prepared with a fiber length of 35 mm and volume fractions of 0.70% displayed the lowest slump value (28 mm) and highest compressive strength (31.5 MPa) at 28 days. In addition, the specimens made with fiber volume fractions of 0.10, 0.20, 0.30, and 0.40% showed a significant improvement in the splitting tensile and flexural strengths. However, increasing the volume of the jute fibers up to 0.50% led to a slight drop in the fracture strength of the geopolymers. The specimens prepared with a length of 25 mm and a volume of 0.40% achieved the highest enhancement of splitting tensile strength (18.7%) and flexural strength (29.1%) at 28 days. In short, sustainable geopolymer concrete with high fracture performance can be obtained by incorporating natural jute fibers, leading to practical applications in the construction sector. The proposed green concrete may enable a reduction in solid waste, thus promoting a more sustainable concrete industry.