Development of low-cost ultra-high performance low-carbon concrete

According to the Portland Cement Association (PCA), ultra-high performance concrete (UHPC) is ‘‘a high-strength, ductile material formulated by combining Portland cement, silica fume, quartz flour, fine silica sand, high range water reducer, water, and steel or organic fibres. The material provides compressive strengths up to 29,000 lb per square inch (psi) and flexural strengths up to 7000 psi”. Over the past decades, a significant number of studies have been undertaken to investigate the properties of UHPC for different applications. There are 2 main obstacles that prevent the extensive application of UHPC in the construction industry. Firstly, the material cost of UHPC is very high compared to normal strength concrete (NSC) and high-performance concrete (HPC). Secondly, a high amount of cement is used in the mixture design of UHPC which results in high shrinkage, heat of hydration, and cost of the material and can compromise the material sustainability performance of UHPC. To tackle these issues, this project aims to develop an UHPC that is low-cost and low-carbon by using low-carbon binders (as a complete replacement of cement) and recycled materials and fibres (as partial/complete replacement of virgin materials and fibres).