Numerical analysis of thermal cracking estimation of mass concrete with GGBS at an early age

2021 ◽  
Vol 0 (0) ◽  
pp. 0-0
Author(s):  
Moustafa Shawkey ◽  
Ahmed Hassan ◽  
Mohamed Rashad
2017 ◽  
Vol 25 (3) ◽  
pp. 8-14 ◽  
Author(s):  
Juraj Bilčík ◽  
Róbert Sonnenschein ◽  
Natália Gažovičová

Abstract This paper focuses on the causes and consequences of early-age cracking of mass concrete foundation slabs due to restrained volume changes. Considering the importance of water leaking through cracks in terms of the serviceability, durability and environmental impact of watertight concrete structures, emphasis is placed on the effect of temperature loads on foundation slabs. Foundation slabs are usually restrained to some degree externally or internally. To evaluate the effect of external restraints on foundation slabs, friction and interaction models are introduced. The reinforcement of concrete cannot prevent the initiation of cracking, but when cracking has occurred, it may act to reduce the spacing and width of cracks. According to EN 1992-1-1, results of calculating crack widths with local variations included in National Annexes (NAs) vary considerably. A comparison of the required reinforcement areas according to different NAs is presented.


2019 ◽  
Vol 99 ◽  
pp. 191-202 ◽  
Author(s):  
Zhifang Zhao ◽  
Kejin Wang ◽  
David A. Lange ◽  
Hougui Zhou ◽  
Weilun Wang ◽  
...  

2010 ◽  
Vol 163-167 ◽  
pp. 2731-2737
Author(s):  
Jin Sheng Du ◽  
Xiao Feng Luo ◽  
P.L. Ng ◽  
Francis T.K. Au

Heat generation of concrete during hardening causes early age temperature rise, and if the associated tendency of volume change is restrained, thermal stresses would be induced and early thermal cracking would result. This issue should be duly considered in concrete bridge construction as the bridge piers as well as other structural members are typically mass concrete members. In this paper, a real-life bridge pier is selected for study. The pier was instrumented to measure its early age temperature rise on site. Finite element analysis was conducted to evaluate the time variations of temperature distributions and thermal stresses induced in the bridge pier. The measurement and analysis results threw light on the evaluation of risk of thermal cracking and planning of temperature control measures in similar projects.


Author(s):  
Andrew Z. Boeckmann ◽  
Zakaria El-tayash ◽  
J. Erik Loehr

Some U.S. transportation agencies have recently applied mass concrete provisions to drilled shafts, imposing limits on maximum temperatures and maximum temperature differentials. On one hand, temperatures commonly observed in large-diameter drilled shafts have been observed to cause delayed ettringite formation (DEF) and thermal cracking in above-ground concrete elements. On the other, the reinforcement and confinement unique to drilled shafts should provide resistance to thermal cracking, and the provisions that have been applied are based on dated practices for above-ground concrete. This paper establishes a rational procedure for design of drilled shafts for durability requirements in response to hydration temperatures, which addresses both DEF and thermal cracking. DEF is addressed through maximum temperature differential limitations that are based on concrete mix design parameters. Thermal cracking is addressed through calculations that explicitly consider the thermo-mechanical response of concrete for predicted temperatures. Results from application of the procedure indicate consideration of DEF and thermal cracking potential for drilled shafts is prudent, but provisions that have been applied to date are overly restrictive in many circumstances, particularly the commonly adopted 35°F maximum temperature differential provision.


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.


2021 ◽  
Vol 54 (6) ◽  
Author(s):  
Jianda Xin ◽  
Yi Liu ◽  
Guoxin Zhang ◽  
Zhenhong Wang ◽  
Ning Yang ◽  
...  

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