Isothermal Strength Development Models of Ultra-High-Performance Concrete

Ultra-high-performance concrete (UHPC) has progressively gained interest because of its favorable strength and durability properties. Considering applications of heat treatment and mass concrete, understanding the direct relationship between curing temperature and time is informative for construction decisions (such as formwork type and time of removal) to maximize performance per unit cost of UHPCs, as they can differ from conventional concrete. Limited datasets are currently available to ascertain the degree of change related to UHPC mechanical properties as a function of curing temperature and conditions. This study presents a systematic experimental program to investigate the effect of isothermal and submerged conditions on the rate and extent of compressive strength and elastic modulus development for UHPC, followed by development of numerical models that capture these effects with reasonable accuracy. Although the final elastic modulus appears to be unaffected by temperature, much higher compressive strength was achieved with higher curing temperatures compared to ambient conditions, and both properties were successfully modeled.