Effect of Fibres on Tension Stiffening Behaviour of Binary Blended Ambient Cured Geopolymer Concrete

Geopolymer concrete is often cited as a promising sustainable material due to its lower environmental impact compared to traditional Portland cement-based concrete and utilizes industrial by-products as its raw materials. Addition of fibres to concrete can significantly improve its performance characteristics, making it beneficial for a wide range of construction applications. Advantages of basalt fibre are its corrosion resistance, light weight and thermal stability, and it possesses comparable tensile strength than steel fibres. Tension stiffening is a key phenomenon in fibre-reinforced concrete that enhances its performance under tensile stress. This provides critical insights into the post-cracking behaviour of fibre-reinforced concrete. Tension stiffening enhances the stiffness, crack control and load-bearing capacity of reinforced concrete in tension zones, improving structural durability and serviceability. Therefore, this study attempts to investigate the tension stiffening behaviour of ambient cured binary blended geopolymer concrete with varying dosages of basalt fibre (0.25, 0.5, 0.75 and 1% of volume). Specimen of size 60 × 60 × 600 mm with 10 mm diameter bars axially reinforced is subjected to uniaxial tensile load. Properties like crack width, crack spacing and deformation were recorded for each load increment. From the study, it can be concluded that the addition of basalt fibres improved the strength and tension stiffening characteristics of binary blended GPC.