Influence of environmental exposure conditions on mechanical properties of high-strength concrete

High-strength concrete (HSC) is regularly used for prestressed concrete bridge girders. Producers of prestressed concrete often have to modify their mixture proportions due to environmental conditions and time of day when casting to achieve the required release strengths. In addition, the properties of the concrete at later ages have to be sufficient such that the design requirements for the service and ultimate limit states are met. This research investigated the influence of temperature and humidity on the compressive strength and flexural tensile strength of HSC mixtures at different ages. Results were compared with standard prediction equations, including the expression used by the American Association of State Highway and Transportation Officials (AASHTO) for estimating the flexural tensile strength. It was determined that early-age environmental exposure conditions can influence the mechanical properties of HSC and new equations, based on environmental exposure factors, may be applicable.