Study On Temperature Prediction And Control Of Mass Concrete During Construction

With the continuous development of economy,society,and technology,mass concrete has become one of the widely used materials in the field of infrastructure construction.However,concrete is often affected by significant temperature stress during construction.When the temperature stress exceeds the tensile strength of concrete,temperature cracks will appear in the concrete.Therefore,in the construction of large volume concrete,attention should be paid to its temperature control.Based on the above background,this article proposes a reliable modeling method for concrete temperature control system,and designs a reasonable concrete temperature control algorithm to accurately and quickly stabilize the temperature of concrete within the comfort threshold.This article fully combines the research experience of predecessors and analyzes the prediction and control of concrete temperature during construction,mainly focusing on the following aspects for in-depth exploration and research:(1)Based on the heat conduction equation and boundary conditions,the temperature field of concrete is modeled,including two parts: the modeling of environmental factors and the modeling of the average temperature of concrete pouring.The concrete temperature prediction curve can be obtained through the finite difference algorithm.When the molding temperature is 26 ℃,the temperature curve presents a trend of rising first and then falling.The maximum temperature of each plane layer of the concrete bottom plate during the pouring stage is 48.04 ℃.The cooling water measures are adopted.The average temperature of the concrete cooling level is modeled through theoretical derivation,and the average temperature of the concrete pouring is simulated using MATLAB.(2)Based on model predictive control theory,the mathematical model of concrete temperature is discretized.This paper proposes a concrete temperature cooling water flow control strategy based on the MPC algorithm.According to the temperature control index requirements in the "Mass Concrete Construction Specification",the simulation results of concrete temperature cooling water flow control are obtained using the MPC controller built by SIMULINK.The results show that the temperature of concrete circulating water can be calculated according to the reference trajectory based on the prediction model,and the error can be controlled within a reasonable range,with the temperature fluctuation range not exceeding 1 ℃.(3)Taking the temperature control of a large volume concrete project of a bridge as the research object,through engineering practice,the performance testing of concrete engineering is evaluated,and the measured data collected by sensors are processed to obtain the change rule of concrete temperature distribution.