Study Of Aqueduct Concrete Temperature Control And Crack Prevention Based On Tensile-pressure Creep At Early Age

In modern water conservancy projects,aqueducts are widely used in water diversion projects as an important crossing structure.With the increasing demand for engineering quality,the application of high performance concrete in aqueducts has become more widespread.High-performance concrete has higher strength,impermeability and durability than ordinary concrete because of its lower water-binder ratio and higher cement content,but its temperature shrinkage and self-shrinkage are also greater than those of ordinary concrete.During the construction period,during the early age of high-performance concrete,the hydration reaction of cement will release a large amount of thermal energy,leading to a rapid increase in its internal temperature.Because of the good heat dissipation performance of the concrete surface,the temperature is relatively low.Because of the huge temperature difference between the concrete surface and the interior,it is easy to produce cracks that penetrate the concrete,which poses a great threat to the stability and durability of the concrete structure.Therefore,in the early age of high-performance concrete to take temperature control measures to prevent the occurrence of temperature cracks.Creep is a very important influencing factor for concrete,especially for tensile creep that is often overlooked.Grasping the creep and creep properties of high-performance concrete at early age can also help provide more accurate concrete temperature control and crack prevention.Based on the above problems and combined with the Puyang River aqueduct in the South-to-North Water Diversion Project,this paper conducts temperature-control and crack-prevention simulation studies on the influence of tensile creep of early-age high performance concrete.The main research contents of this article are as follows:(1)In the calculation of the concrete stress,the factor of early extension and creep is introduced to help accurately predict the development process of the concrete stress field.The presence of tensile creep in high-performance concrete at early age can reduce the tensile stress in the structure and have a certain relaxation effect on the tensile stress of the structure.(2)Using the approximate calculation method,the classical concrete compression creep prediction model is approximately replaced by the concrete tensile creep prediction model.The calculation results are coMPared with the experimental data,and the applicability of the approximatecalculation method is analyzed.(3)Through the regression analysis of previous experimental data,a mathematical model that can describe the tensile creep process of high-performance concrete at early age is fitted,and through simulation calculation,it is verified whether the fitted mathematical model can accurately express the tensile creep.the process of.(4)The computer software was used to simulate the temperature field and stress field during the construction period of the aqueduct.The concrete elastic modulus,hydration reaction,temperature change,structural form,and creep type were comprehensively considered.The finite element model was built in layers to achieve high performance concrete.Structural temperature and stress field simulation calculations.(5)Combining with the actual situation of the aqueduct project,the rationality of the temperature control and crack prevention measures is analyzed by means of simulation,and the extent to which the stress caused by the tensile creep in the actual project can be induced is coMPared and analyzed to provide temperature control and crack prevention for similar projects.for reference.