Study On The Hydration Heat Temperature Effect Of Concrete In The Construction Stage Of Thick-walled Hollow High Pier

In the early curing of concrete, because of the cement and cementing materials inconcrete is reacting with water, the hydration heat reaction of concrete will produce lots of thehydration heat, which lead to the temperature of the concrete gradually increased. To thestructure of the average size, because of the better heat dissipation conditions inside andoutside on concrete structure, they can not produce larger hydration heat temperature. And theconcrete structures deformation is basically the same, where the concrete member will not orrarely produce hydration heat crack. However, To the structure of the mass concrete that therelatively large size for the concrete structure, including lots of content and cementingmaterials and phenomenon of the hydration reaction is significant, that lead to the concretehydration heat temperature rise more faster and higher. But due to the low thermalconductivity of concrete, the concrete surface is lost heat fast and temperature also dropsquickly. At the same time, concrete internal accumulation heat can not transfer to the concretestructure as soon as possible, which leading to high internal temperature and low externaltemperature on the concrete structure, so the temperature gradient begin to appear. Thetemperature gradient will lead to concrete structure have uneven deformation temperature,and when the block of concrete structures subjected to internal or external constraints, unevendeformation will produce large thermal stress. If in some improper cases for control orhandling of the thermal stress, the thermal stress will exceed the tensile strength of concretecaused by cracking of concrete surface, which brings hidden trouble to the durability andsafety of concrete structure.In this paper, it is through the study of field living test of heat temperature on the stage ofconstruction of a railway thick-walled hollow high pier concrete hydration heat found that, thehydration heat temperature harmful crack for thick wall hollow high pier in concreteconstruction. In order to fully analyze the generation mechanism of temperature crack of thehydration heat reaction, this paper first using the finite element theory analysis method,established to simulate the mathematical model with the finite element calculation. So thephysical model of qualitative analysis be changed into a mathematical model of quantitativeanalysis by the physical model into the finite element theory. Then compared with the thickwall hollow high pier of the actual engineering field living test results and finite elementanalysis results, which the produce and development rules and distribution of hydration heattemperature and the hydration heat thermal stress of concrete in the construction of hydrationheat reaction can be find easily. It is also can summarize the fundamental causes of concreteconstruction stage of hydration heat temperature harmful cracks. At the same time, what canillustrate the construction process of thick wall hollow high pier is that, concrete hydration heat temperature effect of temperature stress is beginning to affect the safety of concretestructure durability and service, so in the design and construction should be in accordancewith the mass concrete structure design and construction. Finally, according to the reason ofthe hydration heat of concrete temperature crack, it is found t the control methods of the timeinterval of the concrete placement and the control methods of concrete pouring layer thicknessthat can prevent and control temperature cracks in process of concrete construction. And theresearch of combination analysis method using actual engineering and the theory of finiteelement on the use of control layer of concrete pouring time interval, and the method tocontrol the thickness of concrete layer casting use, which carries on the discussion and theresearch is feasible and effective to the prevention and control of temperature cracks ofconcrete hydration heat.