Effect of material of post-cooling pipes on temperature and thermal stress in mass concrete

Structures ◽  
2019 ◽  
Vol 20 ◽  
pp. 204-212 ◽  
Author(s):  
Adek Tasri ◽  
Anita Susilawati
2017 ◽  
Author(s):  
Keshi You ◽  
Feng Wang ◽  
Liujiang Wang ◽  
Zhongwei Zhao ◽  
Yun Liu

Vestnik MGSU ◽  
2020 ◽  
pp. 380-398
Author(s):  
Nikolay A. Aniskin ◽  
Nguyen Trong Chuc

Introduction. The concreting of solid structures, such as concrete dams, bridge constructions, foundations of buildings and structures, is accompanied by exothermic heating, caused by cement hydration. Heat, emitted by mass concrete blocks, slowly leaves constructions. A substantial temperature difference frequently arises between the solid concrete centre and its surface. If this temperature difference reaches a critical value, thermal cracking occurs, which destroys structural continuity. Temperature problems and those associated with thermal stress state should be resolved to pre-assess and prevent potential cracking. This problem has enjoyed the attention of specialists, and it has been the subject of numerous research projects. Materials and methods. The overview is based on the information about implemented research projects focused on the thermal cracking of mass concrete dams and its prevention. Computer modeling techniques were applied to develop a mathematical model capable of projecting and assessing the potential cracking of mass concrete. Results. The co-authors have compiled an overview of advanced approaches to the assessment of potential thermal crack formation, contemporary problem-solving methods and selected research findings obtained using the finite element method. The co-authors offer a thermal behaviour/thermal stress state projection methodology for solid concrete, as well as a thermal crack formation assessment methodology. Conclusions. The thermal cracking problem has not been solved yet. The proposed methodology and a projection-oriented numerical model can be used as a reference by civil engineers in the process of designing and constructing concrete gravity dams. It may help to reduce cracking probability caused by heat evolution in cement.


2013 ◽  
Vol 353-356 ◽  
pp. 3256-3262
Author(s):  
Pei Fang Su ◽  
Xing Li Lu

In order to analysis thermal stress of mass concrete accurately, material properties of mass concrete are studied by numerical simulation method, and the equivalent age is introduced to describe the mechanical properties of concrete. The calculation models of concrete mechanical parameters are summarized, and then the calculation procedures are established on the basis of equivalent age. In this way, the temperature and temperature history are considered in these models. Meanwhile, the governing equation and computer program of the thermal stress based on the equivalent age are developed. The comparison of the numerical example using proposed method and conventional FEM method shows that the proposed method performs more adaptable and accurate.


2010 ◽  
Vol 163-167 ◽  
pp. 1291-1295 ◽  
Author(s):  
Min Zhi Liu ◽  
Sheng Qiang ◽  
Zhen Yang Zhu

Bedding cushion cracking in concrete dam is widespread, and has not been completely prevented [1,2]. There are many cracking causes of bedding cushion, including construction difficulty and structure requirements for concrete dam. Based on the method of FEM simulative calculation of temperature and stress fields of mass concrete using water cooling pipes, this paper makes relatively in-depth study on crack mechanism for concrete bedding cushion on rock. It is revealed that all three factors of uneven thickness of bedding cushion, thickness of new dam concrete placed on cushion after off period and foundation gallery upon bedding cushion have great influence on the tensile stress of bedding cushion and should be paid special attention during construction. The calculation results show that the tensile stress of thinner concrete cushion layer is much greater than the thicker one, and the thinner upon new concrete will also make greater tensile stress in cushion. As a result, both the thinner cushion layer and the cushion with thinner new concrete on it would have a bigger chance to crack than others. The mechanism is used to explain reasonably a dam crack in construction. Then some cracking prevention measures, which should have reference value for the construction of bedding cushion, are put forward in this paper.


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