Possibility of Using High Volume Fly Ash to Produce Low Cement Ultra High Performance Concrete

Ultra High Performance Concrete (UHPC) is a new class of concrete that has been developed in recent decades for its exceptional properties of strength and durability. The production of UHPC normally requires the use of large amounts of cement that results in the unsustainable development of this concrete system. Therefore, the study of the use of mineral admixtures will be a good solution to reduce cement consumption while improving the properties of the UHPC is of great practical significance in terms of sustainable construction development. The objective of this study is to use a high volume of fly ash to replace cement for the production of UHPC under both standard- and heat treatment- curing conditions. The results show that it is possible to use fly ash up to 40 and 50% by mass of binder under standard curing conditions and heat treatment conditions, respectively, to make the UHPC with the 28d-compressive strength of over 120 MPa. It means that up to 60% of binder (10% silica fume and 50% fly ash) can be used to produce the low cement ultra high performance concrete.