Simulation Of Hydration Heat Of Mass Concrete And Optimization Of Temperature Control Scheme

Although mass concrete has been continuously expanded and developed in the field of construction,and has been widely used in various large-scale reinforced concrete structures,due to the large heat storage inside the mass concrete,the temperature stress increases,which may affect the service life of concrete components and also easily bring safety risks.This paper uses theoretical analysis,field test and simulation to carry out research,and summarizes the current research progress on temperature crack control of mass concrete,several common temperature control construction technologies and relevant basic theories of mass concrete temperature field.Based on a river bridge in Anhui Province and measured data,a finite element simulation model was established,and combined with theoretical analysis,the influence of different parameters on the temperature field of mass concrete was studied from the perspectives of pipe spacing,flow rate,pipe diameter,number of inlet and outlet,cooling water temperature,environmental temperature,fly ash content and pouring temperature.The variation of temperature field of mass concrete under different factors is studied.According to the results of sensitivity analysis,the weight level of each influencing factor is calculated,and the temperature control scheme is optimized and reasonable construction suggestions are given.The main research contents are as follows:(1)The temperature variation rule of mass concrete is analyzed based on the field measured results;Based on the engineering data and field measurement data,the finite element analysis model of hydration heat of mass concrete was established by using Midas FEA NX to simulate the evolution process of the temperature field of cap with time,and the accuracy of the model was verified according to the measured temperature.(2)Based on the simulation analysis model built in(1),the influence of changes in parameters of the mass concrete pipe cooling system(water pipe spacing,water pipe flow,number of inlet and outlet,cooling water temperature,water pipe diameter)on the cooling effect was studied;The parameters of the tube cooling system,internal temperature,surface temperature and temperature difference on the inner surface were quantitatively analyzed,and the weight level of each influencing factor was calculated according to the sensitivity analysis results.(3)Based on the simulation model,the influence rules of environmental temperature,pouring temperature and fly ash content on the temperature field of mass concrete are analyzed,and the reasonable range of parameters is proposed;Based on the results of parameter sensitivity analysis,the weight proportion of the influence of the above factors on the temperature field was calculated.(4)According to the weight levels obtained in(2)and(3),the calculation method of the maximum temperature difference on the inner surface under different influencing factors is proposed;Based on the results of parameter sensitivity analysis,the temperature control scheme of the cap is reasonably optimized,and economic and reasonable temperature control measures are proposed,and the temperature control effect is compared with that of the original scheme,and reasonable suggestions are proposed for the temperature control scheme of the project according to the research results.Compared with the original scheme,the maximum temperature value of the optimized scheme is reduced by 16.2%,the maximum internal surface temperature difference is reduced by 28.8%,and the stable temperature value is reduced by 13.5%.