Effects of Temperature on Mechanical Property of Set Cement and Analysis Thereof

To characterize the mechanical property of the long set cement under a certain temperature gradient, the nonlinear changing pattern of the mechanical property of set cement at different temperatures was studied, and the causes for the changing pattern was analyzed. Curves describing changes of compressive strength, Young's modulus and Poisson ratio with temperature were drawn using the mechanical properties of set cement at temperatures between 30℃ and 160℃, and a functional equation was established by fitting the mechanical property of set cement with temperature. A nonlinear physical equation taking into account the eff3ects of temperature on the mechanical property of set cement was formulated. Analyses of the physical properties of set cement cured at different temperatures were done with the data obtained through TGA and XRD experiments. Using SEM, the micro morphology of set cement was analyzed, and the inherent causes of temperature affecting the mechanical property of set cement were primarily studied. It was found that at the same time of curing, the mechanical property of set cement had sudden changes at 60℃ and 80℃. At temperatures over 80℃, no obvious difference in the mechanical property was found of the cured set cement. It was also found that at temperatures below the temperature at which the sudden change takes place, the mechanical property changes in a pattern of quadratic function; at temperatures above the temperature at which the sudden change takes place, the mechanical property changes in a pattern of exponential function. Combined with the data obtained from micro analyses, it was found that different hydration products of cement and the different degrees of hydration reactions are what cause the mechanical property of the set cement to have sudden changes.