High Performance Concrete with High Volume Fly Ash

The emphasis of this paper is how to increase the 3-day and 28-day strength of high volume fly ash concrete. By some technical measures, such as improving the initial pozzolanic activity (3 day) of fly ash and decreasing the ratio of water to binding material and increasing the total dosage of binding materials, a concrete with the ratio of fly ash to binding materials between 50 %-70 % can be made. The fluidity of the concrete mix with large dosage of fly ash is very good and the strength at 3 day and 28 day are more than 42.5 MPa and 85 MPa respectively. By determining the pH value and the calcium hydrate content of the paste with large dosage of fly ash and accelerated carbonation test, it is shown that the resistance of the concrete to carbonization has been improved. The concrete with large dosage fly ash has good volume stability.