Impact of mixing and curing temperatures on fresh and hardened states properties of UHPC

Abstract

New Canadian and American standards for concrete and bridges now provides guidelines for the design, production, curing, material characterization and installation of Ultra-High Performance Fiber Reinforced Concretes (named UHPFRC or UHPC) on structures. However, some technical aspects require more research since fundamental knowledge about UHPC is not as complete as for normal strength concretes (NSC). Among these aspects, knowledge on the properties of UHPC produced under field conditions is scarce. The main goal of the research project was to evaluate the fresh state properties (slump flow, air content, mass density, hydration heat) and hardened state properties (elastic modulus, Poisson ratio, compressive and flexural strengths) of a UHPC subjected to various mixing temperatures (10, 20 and 30°C) and curing temperatures (10, 23 and 35°C) encountered in field conditions. The impact of mixing and curing temperatures on each property is discussed and practical information is provided to help engineers planning the UHPC curing duration and formwork stripping.