Methodology for Identifying Zero-Stress Time for Jointed Plain Concrete Pavements

作者：Nassiri Somayeh; Vandenbossche Julie M^*; Janssen Donald J

来源：Transportation Research Record, 2014, 2441(2441): 62-71.

DOI：10.3141/2441-09

This study focused on identifying the zero-stress time (TZ) in jointed plain concrete pavements (JPCPs). TZ is the time when the concrete slab is sufficiently strong to deform (thermally expand or contract and thus curl) despite the existing external restraints, including the friction at the base-slab interface. It is critical to be able to identify TZ so that the temperature gradient present in the slab at TZ, known as the built-in temperature gradient, can be characterized. In this study, TZ was established through the instrumentation of 36 concrete slabs in four JPCP construction projects. Strain-temperature behavior in each slab was used to identify TZ. The slabs in each project were paved at different times of the day (morning, noon, early afternoon, and late afternoon) to investigate the effects of the ambient curing conditions on TZ. The degree of hydration at TZ (alpha(TZ)) was established for each slab. The field data were used in the development of a model for predicting alpha(TZ) as a function of the concrete water-to-cement ratio, unit weight, early-age elastic modulus, and slab thickness.

• 出版日期2014