Daily Cycles of Temperature-Independent Curvature in Jointed Plain Concrete Pavements

Curvature due to temperature curling and moisture warping has a large effect on the performance and assessment of jointed plain concrete pavements (JPCP). Accurate curvature prediction can improve the design and evaluation of these structures. Daily changes in curvature are often assumed to be solely dependent on the temperature. However, data from instrumented slabs indicate that a hysteresis loop occurs on the equivalent linear temperature gradient (ELTG) versus curvature plot. A method is introduced to characterize the hysteresis loop by a characteristic height. This parameter is found to follow long-term and seasonal patterns. The characteristic height is correlated to the amplitude of the daily relative humidity cycle, indicating that the hysteresis loop may be affected by daily moisture movement within the slab. A method is introduced to identify the components of strain independent of temperature and restraint. These temperature-independent and restraint-independent strains are used to probe the long-term and seasonal changes in the hysteresis behavior. (C) 2017 American Society of Civil Engineers.