Experimental Study On Thermal Parameters And Temperature Simulation Of RCC Considering Fly Ash Content

For mass concrete hydraulic structure,high hydration heat increasing temperature difference between inside and outside,then there will be a temperature stress and temperature stress cracks can lead to high building,and the temperature crack and seriously affects the safe and stable operation of hydraulic structures,at present,the research of mass crack control of the hydraulic structures is very important and necessary.To reduce the inside of the mass concrete temperature stress,often in the design of concrete mixed with a certain amount of fly ash,due to the hydration of fly ash little heat,so the concrete hydration heat temperature rise will be greatly reduced,so that it can effectively reduce the inside of the mass concrete temperature stress,prevent the occurrence of cracks,guarantee the building safety and stability.This article through carries on the different dosage of fly ash roller compacted concrete adiabatic temperature rise test,study the dosage of fly ash roller compacted concrete adiabatic temperature rise and the effect of analysis of roller compacted concrete adiabatic temperature rise along with the change and change the laws of the dosage of fly ash,and used the results measured in experiment of a RCC gravity dam temperature field stress field simulation calculation,based on the calculation results of comparative analysis,which can be used as a reference for practical engineering.The adiabatic temperature appreciation of concrete is an important thermodynamic parameter in the temperature control simulation calculation.The adiabatic temperature rise test of RCC with 10%,20%,30%,40%,50%fly ash content and normal concrete control group with 0%fly ash content are carried out according to the ratio of experimental specifications.When the fly ash content is 0%,10%,20%,30%,40%,50%,The measured adiabatic temperature appreciation is 34.653℃,31.108℃,27.8115℃,24.115℃,20.334℃ and 16.456℃ respectively.According to the measured data to map the 6 kinds of adiabatic rise of temperature curve,the dosage of fly ash on the adiabatic rise of temperature between fly ash and relationship analysis,using the elliptic type and index of adiabatic temperature rise formula of temperature data fitting,according to the fitting results,the fitting results of hyperbolic formula are relatively poor and the fitting degree is small,The fitting result of exponential formula is well and the fitting degree is high.With the increase of fly ash content,the adiabatic temperature rise curve is more and more gentle,and the heat release peak of concrete is delayed.According to the test,the adiabatic temperature rise data of six groups with different fly ash contents and various engineering data are measured,the finite element simulation calculation of temperature field and stress field of RCC gravity dam during construction period and operation period is carried out,and the comparative analysis is made according to the results obtained from the simulation calculation,with the decrease of fly ash content,the maximum temperature and the maximum stress of the dam become higher and higher,and the peak value of temperature and stress duration curve becomes higher.Through comparative analysis,when 50%dosage of fly ash,the cooling water of the taken measures at the same time,the temperature field and stress field in order to meet the temperature and stress control standard,so that the RCC dam with 50%fly ash mixing ratio is more appropriate,at the same time the dam in the dam during construction period should be cooling water measures,to ensure dam safety and reliability.