Document Type : Research Paper

Authors

• Adil M. Jabbar
• Mohammed J. Hamood
• Dhiyaa H. Mohammed

Civil Engineering Dept., University of Technology-Iraq, Alsina’a street, 10066 Baghdad, Iraq.

Abstract

Ultra-High Performance Concrete (UHPC) is a new generation of concrete characterized by its high strength, high durability, and high stiffness. Autogenously shrinkage represents one of the issues of UHPC that occurred at early ages. It occurs particularly during the first 48 hours after casting. This paper focuses on the ways that can be depended on to mitigate the autogenously shrinkage and obtain the outstanding mechanical properties of UHPC. The results showed that the use of coarse sand and high dose of high range water reduced the admixture above 5% of cementations of materials weight, and high ambient temperature at the time of mixing and casting led to increasing the autogenously shrinkage. While using fine sand, silica fume at 25% of cement weight, and crushed ice at 50% of mixing water to control the mixing temperature can reduce autogenously shrinkage significantly.

Highlights

• In UHPC, autogenous shrinkage dominates over the drying shrinkage.
• High pouring temperature and coarse sand increase the number and size of pores.
• Increasing silica fume over 25% of cement content reduces compressive strength.
• Adding steel or basalt fibers minimize the inverse effect of autogenous shrinkage.

Keywords

• Autogenously shrinkage
• Cement
• Fly ash
• HRWRA
• Silica fume
• UHPC

Main Subjects

• Civil