scholarly journals Hydration Heat Analysis and Temperature Control on Steel Shell Concrete Immersed Tube during Precasting

2021 ◽  
Vol 783 (1) ◽  
pp. 012029
Author(s):  
Wenhuo Sun ◽  
Meimei Liu ◽  
Ting Ji
2011 ◽  
Vol 71-78 ◽  
pp. 4134-4137
Author(s):  
Ya Xun Yang

For the hydration heat generated by the massive concrete during the construction of the pier’s base, the methods and operation processes of temperature control are presented in this article, using the finite element program MIDAS analyze the massive concrete temperature field of the hydration heat during the construction of the base. Besides, temperature control program for the construction of massive concrete, simulation of the calculation result and controlling calculation following the process of the construction compared with the data of temperature monitoring are introduced. The result of analysis and calculation could be a reference for the similar construction.


2012 ◽  
Vol 594-597 ◽  
pp. 1509-1515
Author(s):  
Chun Jiao Lin ◽  
Gen Gen Fu ◽  
Lei Lei Guo

Based on the experimental study into the temperature control scheme for mass concrete pile caps of the Zhenyuling Bridge, this paper did comprehensive research on effective ways to reducing massive concrete temperature caused by hydration heat, and preventing concrete cracks caused by thermal stress. The paper analyzed the effects of cooling pipe, concrete thickness and surface insulation materials on the temperature-stress field of massive concrete. By theoretical analysis and simulation research, the temperature control scheme was developed to guide the construction of massive concrete. Temperature-controlling techniques and precaution measures of early thermal cracks are introduced, which can provide reference to construction similar structure.


2020 ◽  
Vol 2020 ◽  
pp. 1-17
Author(s):  
Wenqiang Xu ◽  
Sheng Qiang ◽  
Zhengkai Hu ◽  
Bingyong Ding ◽  
Bingyong Yang

Concrete hydration heat inhibitor can inhibit the early hydration reaction of concrete and reduce the initial heat release of concrete. However, there is no in-depth research on the effect of hydration heat inhibitor on hydraulic structures with different thicknesses and constraints. In this paper, numerical simulation is used to study the change of temperature and stress field after adding hydration heat inhibitor by establishing the finite element models of tunnel lining, sluice, and gravity dam. The results show that the effect of the hydration heat inhibitors on reducing the temperature peak is inversely proportional to the thickness of the structure. A formula is put forward to evaluate their relation in this paper. When the thickness of the structure is about 6 m, there is no peak cutting effect. For the stress field, hydration heat inhibitor can greatly reduce the thermal stress of the thin-walled structure and make the structure meet the temperature control requirements; for the medium wall thickness structure, it can reduce the internal tensile stress about 50% and the surface tensile stress about 20%, and other temperature control measures are still needed to ensure that the surface tensile stress of the structure meets the requirements; for hydraulic structures with large volume and thickness, the application effect of the inhibitor has limitations, which can reduce the internal tensile stress about 30%, but the tensile stress in the surface area will increase about 7% due to the increase of the internal and external temperature difference; therefore, other temperature control measures such as arranging cooling water pipe, strengthening surface insulation, and so on are needed to ensure that temperature cracks do not occur. This paper provides references and suggestions for the research and engineering application of hydration heat inhibitor.


2011 ◽  
Vol 243-249 ◽  
pp. 1589-1596
Author(s):  
Xu Hui He ◽  
Hao Cheng ◽  
Hong Xi Qin

The temperature control of mass concrete is regarded to be a universal problem. Because of the heavy load of railway cable-stayed bridges, the pile caps usually have large dimensions, so the thermal stress, which is caused by hydration heat, must be emphasized. In order to study the spatial distribution of temperature in mass concrete and find a functional temperature control measure during construction, the theoretical and FEM analysis of hydration heat-thermal stress field are applied, which can improve structural reliability and provide reference for design and engineering of the similar project. Based on FEM calculation, the theoretical hydration heat temperature field is obtained. In the same time, the temperature sensors as well as strain sensors are arranged in the key position of pile cap. Then the variation of hydration temperature in concrete would be measured and recorded since the concrete is pouring. According to the theoretical simulation and the monitoring results, the time-history curve of hydration heat is obtained, and the variation of inner temperature gradient along the height direction as well as the longitudinal direction with the concrete age are studied, and the feasibility of temperature control measures is also verified.


Author(s):  
P.R. Swann ◽  
A.E. Lloyd

Figure 1 shows the design of a specimen stage used for the in situ observation of phase transformations in the temperature range between ambient and −160°C. The design has the following features a high degree of specimen stability during tilting linear tilt actuation about two orthogonal axes for accurate control of tilt angle read-out high angle tilt range for stereo work and habit plane determination simple, robust construction temperature control of better than ±0.5°C minimum thermal drift and transmission of vibration from the cooling system.


1981 ◽  
Vol 26 (8) ◽  
pp. 636-637
Author(s):  
James M. Lipton
Keyword(s):  

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