The Study On Heat Transfer Characteristics Of Concrete Based On Hydration Degree

The hydration of cement is affected by many factors,such as water cement ratio,specific surface area,cement composition and temperature.These factors will affect the hydration heat release,heat release power and final hydration degree of cement.With the progress of cement grinding technology,the cement is more and more fine,and the specific surface area of cement is also increased,which affects the hydration process of cement.Therefore,it is necessary to further study the hydration process of cement to make the model closer to the reality.Aiming at the existing problems,this paper studies the influence of large specific surface area and high temperature on the hydration heat release of cement,and puts forward the final hydration degree equation.Based on the research results and finite element software,the temperature distribution law of early age concrete is studied.The main contents of this paper are as follows:In this paper,the influence of water cement ratio,specific surface area and temperature on the heat release power and heat release of cement hydration is studied through the test of cement hydration heat.When the temperature and water cement ratio are constant,the larger the specific surface area of cement,the greater the hydration heat release power and heat release.When the water cement ratio and specific surface area are constant,the higher the hydration temperature,the greater the hydration heat release power and heat release.The maximum value of hydration heat release power appears in 3h-16 h,and the maximum value of hydration heat release is 1900J-4200 J.When the temperature and specific surface area are fixed,and the water cement ratio is about 0.4,the cement can be completely hydrated.At this time,the heat release power of cement hydration is the largest.In 0-72 h,the greater the water cement ratio is,the greater the heat release of cement hydration is.However,the maximum heat release power when the water cement ratio is 0.6 is less than that when the water cement ratio is 0.4.Based on the test results,the final hydration degree formula is proposed by using data regression method.The formula considers the influence of water cement ratio,specific surface area and temperature on the hydration process at the same time.The formula is verified and the results fit well with the test data.Based on the final hydration formula proposed in this paper,the adiabatic temperature rise model is modified,and the temperature distribution of concrete is studied by using the finite element software MADIS and numerical simulation method.The results show that the results are closer to the simulation value of experimental data.