Mechanical Properties and Autogenous Shrinkage of Ultra High Performance Concrete Using Expansive Admixture and Shrinkage Reducing Agent depending on Curing Conditions

Abstract

This paper examines the mechanical and autogenous shrinkage characteristics per curing condition of Ultra High Performance Concrete (UHPC) according to the change in the quantities of expansive admixture and shrinkage-reducing agent. In view of the mechanical properties according to the curing condition, all the UHPC specimens that experienced steam curing at 90℃ developed compressive strength higher than 190 MPa, and the specimens that experienced water curing at 20℃ developed compressive strength comparable to that developed at 91 days by the steam-cured specimens. The specimens steam-cured at 90℃ showed high tensile strength of 23.4 MPa whereas slight loss of the tensile strength was observed in those water-cured at 20. Besides, in view of the autogenous shrinkage according to the curing condition, no particular change could be found in the final shrinkage. The compressive strength developed by UHPC according to the use of expansive and shrinkage-reducing agents reached values higher than 190 MPa in case of steam curing at 90℃. Shrinkage reduced by about 45% when using both expansive and shrinkage-reducing agents without difference according to the curing condition.