Experimental study on temperature stress calculation and temperature control optimization of concrete based on early age parameters

Temperature control curve is the key to achieving temperature control and crack prevention of high concrete dam during construction, and its rationality depends on the accurate measurement of temperature stress.With the simulation testing machine for the temperature stress, in the present study, we carried out the deformation process tests of concrete under three temperature curves: convex, straight and concave.Besides, we not only measured the early-age elastic modulus, creep parameters and stress process, but also proposed the preferred type.The results show that at early age, higher temperature always leads to greater elastic modulus and smaller creep.However, the traditional indoor experiments have underestimated the elastic modulus and creep development at early age, which makes the calculated value of temperature stress too small, thus increasing the cracking risk.In this study, the stress values of the three curves calculated based on the strain and early-age parameters are in good agreement with the temperature stress measured by the temperature stress testing machine, which verifies the method accuracy.When the temperature changes along the concave curve, the law of stress development is in consistent with that of strength.Under this condition, the stress fluctuation is small and the crack prevention safety of the concave type is higher, so the concave type is better.The test results provide a reliable basis and support for temperature control curve design and optimization of concrete dams.