Research on thermal- humidity -force coupling characteristics of mass concrete structures under temperature control

Abstract

Hydraulic mass concrete has been in a temperature and humidity cycle environment for a long time, reducing the performance and service life of its structure. Under the premise of temperature control, we use the Soret effect as the basis of heat- humidity coupling, and then use thermal conductivity, diffusion coefficient and elastic modulus to evaluate the coupling effect between temperature, relative humidity, and stress of mass concrete, and establish a thermal – humidity -force coupling model. Using the embedded temperature and humidity sensor to conduct experiments on mass concrete, this study explores the temperature control pipeline's influence on the temperature and relative humidity distribution inside the concrete and the feasibility of the coupling model. Through experimental results and model analysis, this study found that, under temperature control, the prediction results of the coupled model are more consistent with the experimental results, and its accuracy is higher than that of the uncoupled model. In the process of temperature control, temperature has a significant effect on surface water diffusion, whereas humidity has little effect on temperature conduction, and temperature conduction is mainly affected by temperature gradient. Temperature control can effectively reduce the temperature amplitude inside the concrete, reducing the stress inside the concrete. Moreover, the coupled thermal-moisture-force model can accurately predict the variation trend of temperature, relative humidity, and stress with time at each point inside the concrete under temperature control. The theoretical results of this study can provide a reference for the design, construction, and maintenance of hydraulic engineering structures in the future and better grasp the internal temperature, relative humidity, and stress of hydraulic concrete in different environments and the change law.