Shrinkage of ultra-high strength concrete

This paper presents results from shrinkage tests conducted on ultra-high strength concrete (UHSC) mixtures produced using materials local to New Mexico, USA. The two UHSC mixtures investigated had 28 day compressive strengths of 170.3 MPa for UHSC with steel fibres (fibre reinforced) and 159.9 MPa for UHSC without fibres (plain). Early-age (less than 24 hours) shrinkage of plain UHSC was 54.9% greater than the early-age shrinkage of fibre reinforced UHSC. Total shrinkage (sum of early-age shrinkage and longer term shrinkage) of plain UHSC was 50.6% greater than that of fibre reinforced UHSC after heat curing. The lower shrinkage of fibre reinforced UHSC is attributed to the restraining influence of the steel fibres. Total shrinkage values of heat cured, plain and fibre reinforced UHSC specimens were 4251μ and 2822μ, respectively. These values were 25.2% and 19.6% greater than the shrinkage values for air cured, plain and fibre reinforced UHSC, respectively.