Process and prediction of moisture and temperature distributions and history in hardening concrete.

摘要

The essential factors that determine the quality of concrete structure or its thermal cracking tendency are the relative humidity and temperature distribution varying with time. This study develops mathematical models for the prediction of relative humidity and temperature distribution and history for concrete in an attempt to help understand the curing efficiency and cracking tendency. These two models appear as nonlinear and linear time-dependent partial differential equations, respectively. They are solved via the finite element method. The environmental conditions, the hydration of cement that generates internal heat and the dependence of diffusivity of concrete on the humidity are considered in the models. An experimental and numerical program is developed to determine the material properties of concrete immediately after casting. Back-calculation of concrete diffusivity and thermal conductivity are also performed. Relative humidity and temperature predictions are compared with laboratory and field tests measured data.