Assessment of cracking in concrete due to hydration heat and autogenous shrinkage
An experimental study was conducted to simulate the generation of thermal stresses due to hydration heat and restraint by using a thermal stress measuring device (TSD). The net effects of time-dependent properties of hardening concrete can be well incorporated in TSD due to simultaneous development of temperature and corresponding stress in restrained specimen. Moreover, experiments were conducted to measure a precise value of early-age autogenous shrinkage (AS) and to evaluate the basic creep model with respect to AS. In cracking risk analysis, precise value of early-age AS must accurately predict the time of shrinkage-induced cracking. A significant difference exists between apparent (including AS) and real basic creep (excluding AS) for low water-cement ratio concrete and early-age normal strength concrete. To improve the crack sensitivity analysis, it is recommended to precisely measure early-age AS and modify the basic creep model to prevent from possible errors and computational problems.
Keywords: autogenous shrinkage, early-age shrinkage, hydration heat, thermal stress measuring, basic creep, concrete cracking, simulation, crack sensitivity analysis, structural engineering