Super high early strength cement: ambient cured compressive strength exceeding 24 MPa within 4 h after mixing

A blended hydraulic cement with a normal setting behaviour but rapid strength gain has been developed. This blended cement is a mixture of Portland cement and high alumina cement with the inclusion of other admixtures in order to accelerate early strength and prolong setting time. Concrete made from this cement obtained a compressive strength that exceeded 24 MPa within 4 h after mixing. A practical example of the utilisation of this cement in concrete used for repairing the expansion joints between slab decks on a fly-over bridge across an intersection is presented herein. This concrete had an initial slump of 20 cm, setting time of 100 min and compressive strength of 25·4 MPa at 3 h after placing.