Case Studies in Construction Materials (Jul 2024)
Time-dependent properties of steam cured non-proprietary ultra high-performance concretes
Abstract
Steam curing of ultra-high-performance concrete (UHPC) has been a common practice to accelerate its material properties development in research and field applications. The time benefits of steam curing come with additional energy demands and CO2 emission. In this research, the effect of steam curing duration on development of UHPC material properties is systematically investigated on four non-proprietary UHPC matrices and two fiber reinforced UHPCs, and fills this current knowledge gap. Investigated material properties includes compressive strength, dynamic modulus of elasticity, electrical surface resistivity and shrinkage. Empirical relationships between these material properties and the duration of steam-curing were derived and compared to available results and relationships from other researchers. In addition, the results were compared to those from regular curing conditions. These research findings might be useful for the precast industry to tailor their energy input, fuel consumption and CO2 emission to the accelerated gain of material properties of non-proprietary UHPC developed using locally available materials. The results show that after 24 h of steam curing at 90 °C the compressive strength and dynamic modulus of elasticity of developed UHPC matrices and fiber reinforced UHPCs exceed 170 MPa and 60 GPa, respectively. In addition, the electrical surface resistivity exceeds 1000 K-ohm-cm and shrinkage is less than 0.04% after 24 h of steam curing. These properties surpass the properties when compared to 28 days of regular curing.
