The development of Mechanical property and Hydration Characteristics of concrete at negative temperature environment

摘要

The development of the concrete mechanical properties and the characterization of hydration degree of the high performance concrete under negative temperature curing condition in plateau environment were studied. The results indicate that the concrete casted at the temperature below -10°C must be mixed with the early strength antifreeze admixture with the optimum dosage, and other thermal insulation curing measurements should be taken at the same time. The process of concrete setting and hardening can be promoted, and the early strength can be increased. The strength of c30 concrete mixed with antifreeze admixture increases slowly under the negative temperature. Even though the samples are transferred into standard curing condition after being cured under the negative temperature condition for 3d and 7d, the concrete strength are still lower than the concrete cured under the standard condition with the identical age, the 56d concrete strength of negative temperature are close to the 28d strength of standard curing concrete. The effect of the negative temperature curing in the early stage on the development of concrete hydration degree is similar to the effect on compressive strength. The relation between the hydration degree and maturity degree is established, and the hydration degree can be predicted through the maturity degree of concrete under different curing conditions.