Mathematical Model of Temperature Changes in Concrete Pavements

When concrete pavement is subjected to a change in temperature, some time must elapse before a condition of equilibrium is again reached. In the transient heating and cooling processes that take place in the interim, there are three basic energy transfer modes: (1) Radiant; (2) convective; and (3) conductive heat transfer. As a concrete pavement's thermal environment changes, the physical mechanisms that underlie the heat‐transfer modes cause fluctuating temporal zones to occur within the pavement slab. For instance, during a freeze‐thaw cycle the upper portion of the pavement may be subject to thawing and refreezing while the bottom portion of the slab remains frozen. By using a finite‐difference computer model coupled with field and laboratory observations, the writers discuss how the rate and depth of temperature change can be accurately predicted. Freeze‐thaw cycles in which surface scaling occurred are used to illustrate one of the different kinds of exposure conditions that can be accurately simulated.