Physio-chemical, mechanical and fracture analysis of ultra-high performance cementitious composite

The present research aims to develop cost-effective and environmentally friendly Ultra-High Performance Concrete (UHPC) composite using fly ash and quartz powder as a sustainable alternative to cement. The performance of various constituents is examined, and their influence on fresh and hardened properties is investigated for the optimum trial mix design. The results show that a cube compressive strength of 144 MPa was achieved with fly ash content of 20% and 10% quartz powder and other ingredients without any special heat treatment. Advanced characterization studies such as heat of hydration and X-ray diffraction analysis were performed to understand the performance of fly ash blended UHPC. Further, various fracture properties, such as fracture toughness, fracture energy, brittleness number, etc., were investigated considering geometrically similar notched beam specimens for UHPC mix with 1.5% and 2.5% steel fibre content. The optimum UHPC mix achieved good scores in terms of the strength index and the carbon emission index, indicating the concrete is eco-friendly and sustainable.