Thermal Characteristics of Mat Foundation with Different Lift Thickness of Mass Concrete Including Strontium-Based Latent Heat Binder

2014 ◽  
Vol 525 ◽  
pp. 461-464
Author(s):  
Kyung Lim Ahn ◽  
Qi Bo Liang ◽  
Bae Su Khil ◽  
Hyun Do Yun
Keyword(s):  
Latent Heat ◽  
Temperature Rise ◽  
Volume Fraction ◽  
Heat Of Hydration ◽  
Adiabatic Temperature ◽  
Hydration Heat ◽  
Mass Concrete ◽  
Adiabatic Temperature Rise ◽  
Concrete Foundation ◽  
Mat Foundation

This study provides analytical results for heat of hydration in the mat foundation with mass concretes to investigate the effect of lift thickness in the mat foundation on the hydration heat and crack characteristics of mat foundation with mass concrete. Mass concretes were mixed with ternary cement with 1% strontium-based latent heat binder at volume fraction and Type IV low heat cement. The mat foundation has the dimension of 15m length, 20m width and 3m depth. Lift thickness of mass concrete for mat foundation was varied from 1.0m to 3.0m. A commercial software MIDAS/Gen was used to analyze the hydration heat of mass concrete foundation. The maximum adiabatic temperature rise (K), and the coefficient of temperature rise (α) for thermal analysis were drawn from adiabatic temperature rise test. Based on the results of the finite element analysis for mat foundation with different lift thickness, the highest internal temperature and thermal stress increased with increasing with lift thickness of foundation. However, for foundation constructed with premixed strontium based latent heat binder (PSLB) concrete, this phenomenon was less remarkable compared to mass concrete foundation made with low heat cement.

Influence of Casting Temperature on the Heat of Hydration in Mass Concrete Foundation with Ternary Cements

2014 ◽  
Vol 525 ◽  
pp. 478-481 ◽  
Author(s):  
Mi Hwa Lee ◽  
Young Seok Chae ◽  
Bae Su Khil ◽  
Hyun Do Yun
Keyword(s):  
Temperature Rise ◽  
Heat Of Hydration ◽  
Adiabatic Temperature ◽  
Casting Temperature ◽  
Mass Concrete ◽  
External Temperature ◽  
Maximum Heat ◽  
Adiabatic Temperature Rise ◽  
Concrete Foundation ◽  
Mat Foundation

This study is conducted to evaluate analytically the effect of casting temperature on the heat of hydration in mass concrete foundation with ternary cements and Type IV low heat cement. The mat foundation has the dimension of 15m length, 20m width and 3m depth. Casting temperatures considered for mat foundation consist of 10, 20 and 30C ̊. A commercial software MIDAS/Gen was used to analyze the hydration heat of mass concrete foundation. The maximum adiabatic temperature rise (K), and the coefficient of temperature rise˰˸α˹˰for thermal analysis were drawn from adiabatic temperature rise test. Analytical results show that blended cement PSLB_352 is the most effective to control the heat of hydration in mass concrete foundation and external temperature increases the maximum heat of hydration and crack probability of mat foundation with mass concrete.

Kinetic Model of Adiabatic Temperature Rise of Mass Concrete

2021 ◽  
Vol 13 (5) ◽  
pp. 771-780
Author(s):  
Shou-Kai Chen ◽  
Bo-Wen Xu
Keyword(s):  
Temperature Field ◽  
Temperature Rise ◽  
Initial Conditions ◽  
Dynamic Change ◽  
Adiabatic Temperature ◽  
Model Parameters ◽  
Hydration Reaction ◽  
Mass Concrete ◽  
Adiabatic Temperature Rise ◽  
Proposed Model

The adiabatic temperature rise model of mass concrete is very important for temperature field simulation, same to crack resistance capacity and temperature control of concrete structures. In this research, a thermal kinetics analysis was performed to study the exothermic hydration reaction process of concrete, and an adiabatic temperature rise model was proposed. The proposed model considers influencing factors, including initial temperature, temperature history, activation energy, and the completion degree of adiabatic temperature rise and is theoretically mature and definitive in physical meaning. It was performed on different initial temperatures for adiabatic temperature rise test; the data were employed in a regression analysis of the model parameters and initial conditions. The same function was applied to describe the dynamic change of the adiabatic temperature rise rates for different initial temperatures and different temperature changing processes and subsequently employed in a finite element analysis of the concrete temperature field. The test results indicated that the proposed model adequately fits the data of the adiabatic temperature rise test, which included different initial temperatures, and accurately predicts the changing pattern of adiabatic temperature rise of concrete at different initial temperatures. Compared with the results using the traditional age-based adiabatic temperature rise model, the results of a calculation example revealed that the simulated calculation results using the proposed model can accurately reflect the temperature change pattern of concrete in heat dissipation conditions.

Modeling the Heat of Hydration of Concrete Incorporating Fly Ash

2016 ◽  
Vol 705 ◽  
pp. 332-337 ◽  
Author(s):  
Zheng Gang Lu ◽  
Xiu Xin Wang
Keyword(s):  
Fly Ash ◽  
Temperature Rise ◽  
Heat Of Hydration ◽  
Hyperbolic Type ◽  
Adiabatic Temperature ◽  
Adiabatic Temperature Rise ◽  
Equivalent Age ◽  
Binder Ratio ◽  
Water Binder Ratio ◽  
Release Coefficient

The hydration evolution of concrete with different water-binder ratios and fly ash replacement percentages are studied by experimental investigation. Based on equivalent age concept, the effect of water-binder ratio as well as fly ash dosage on the ultimate temperature rise and heat release coefficient are analyzed with the hyperbolic-type calculating model of adiabatic temperature rise adopted. It is indicated that the adiabatic temperature rise will be reduced with the increase of water-binder ratio and the incorporation of fly ash. The hydration evolution process will be accelerated with the decrease of water-binder ratio, but slowed down when the amount of fly ash is enhanced.

scholarly journals Feasibility of Using Phase Change Materials to Control the Heat of Hydration in Massive Concrete Structures

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Won-Chang Choi ◽  
Bae-Soo Khil ◽  
Young-Seok Chae ◽  
Qi-Bo Liang ◽  
Hyun-Do Yun
Keyword(s):  
Phase Change ◽  
Latent Heat ◽  
Phase Change Materials ◽  
Cement Mortar ◽  
Concrete Structures ◽  
Experimental Tests ◽  
Heat Of Hydration ◽  
Hydration Heat ◽  
Experimental Results ◽  
Mass Concrete

This paper presents experimental results that can be applied to select a possible phase change material (PCM), such as a latent heat material (LHM), to control the hydration heat in mass concrete structures. Five experimental tests (microconduction, simplified adiabatic temperature rise, heat, and compressive strength tests) were conducted to select the most desirable LHM out of seven types of inorganic PCM used in cement mortar and to determine the most suitable mix design. The results of these experimental tests were used to assess the feasibility of using PCM to reduce hydration heat in mass concrete that was examined. The experimental results show that cement mortar containing barium- [Ba(OH)2·8H2O] based PCM has the lowest amount of total hydration heat of the cement pastes. The barium-based PCM provides good latent heat properties that help to prevent volume change and microcracks caused by thermal stress in mass concrete.

scholarly journals Study on Adiabatic Temperature Rise Reflecting Hydration Degree of Concrete

2018 ◽  
Vol 2018 ◽  
pp. 1-12
Author(s):  
Yanhua Han ◽  
Shaojun Fu ◽  
Shufa Wang ◽  
Zuowei Xie
Keyword(s):  
Neural Network ◽  
Temperature Rise ◽  
Bp Neural Network ◽  
Thermal Model ◽  
Concrete Structures ◽  
Thermal Parameters ◽  
Adiabatic Temperature ◽  
Mass Concrete ◽  
Hydration Degree ◽  
Adiabatic Temperature Rise

The thermal model and the relevant parameters of concrete are the most important issues to study the space-time characteristics of temperature field, which are also the theoretical foundation of temperature control and crack prevention for the mass concrete structures. In this research, the improved adiabatic temperature rise test is carried out, and the temperature variation of fly ash concrete is analyzed. Furthermore, a thermal model of concrete considering the hydration degree is established based on the existing achievements. Meanwhile, the thermal conductivity and specific heat of concrete are measured via three approaches: by treating the parameters as constant values, by computing the parameters as variables of the degree of hydration, and by back-analyzing the parameters through BP neural network. Finally, the thermal parameters determined by different methodologies are substituted into the thermal model, respectively, and the finite element analysis of the concrete specimen is performed. By comparing simulated temperatures with various measured results, it can be found that the numerical analysis results of parameters calculated by BP neural network are closest to the measured values in the whole curing ages. Therefore, BP neural network method is an effective way to calculate the thermal parameters, and BP inversion algorithm provides a new way for accurately study the temperature profile of mass concrete structures.

Experimental Study on Influential Factors of Adiabatic Temperature Rise for Mass Concrete

2011 ◽  
Vol 306-307 ◽  
pp. 917-922
Author(s):  
Dong Dong Wang ◽  
Wei Li Tian ◽  
Cheng Qi Wang
Keyword(s):  
Temperature Rise ◽  
Heat Liberation ◽  
Influential Factors ◽  
Adiabatic Temperature ◽  
Mineral Admixtures ◽  
Mass Concrete ◽  
Adiabatic Temperature Rise ◽  
Exothermic Process ◽  
Binder Ratio ◽  
Main Factor

Experiments on adiabatic temperature rise are systematically carried out in this paper, the characteristics of adiabatic temperature rise of concrete with different mineral admixtures are compared. The influence of binder amount, water-binder ratio, placing temperature and superplasticizer is also studied. The results reflect that binder is the main factor affecting adiabatic temperature rise, mineral admixtures such as fly ash can significantly reduce the rate and amount of heat development, large quantity substitution of slag in concrete can relieve the concentrative heat liberation, the retarded superplasticizer can prolong the exothermic process effectively and high placing temperature has adverse effect on temperature control of mass concrete.

Study on the Crack Resistance Properties of Manufactured Sand Concrete

2021 ◽  
Vol 1033 ◽  
pp. 178-182
Author(s):  
Rui Jun Gao ◽  
Hao Wu ◽  
Chao Liu
Keyword(s):  
Tensile Strength ◽  
Elastic Modulus ◽  
Crack Resistance ◽  
Temperature Rise ◽  
Functional Materials ◽  
Adiabatic Temperature ◽  
Mass Concrete ◽  
Adiabatic Temperature Rise ◽  
Manufactured Sand ◽  
Crack Problems

In order to solve the problem of workability and durability of concrete caused by poor particle shape and morphology of manufactured sand and high content of stone powder, which leads to crack problems of concrete, the tensile strength, elastic modulus, shrinkage performance and adiabatic temperature rise performance of manufactured sand concrete were studied in this paper. And the cracking risk factor (the reciprocal of the anti cracking safety factor) of the concrete with the special admixtures and the crack resistant functional materials was calculated by according to GB 50496-2018. The experimental results show that the elastic modulus and tensile strength at the age of 28 d of the test concrete are increased from 31.0 GPa to 34.6 GPA and 2.91 MPa to 4.23 MPa, respectively. The shrinkage performance and adiabatic temperature rise of the concrete are reduced from 98 με to 65 με and 38.9°C to 38.4°C, respectively. The risk factors of surface and center crack resistance of mass concrete floor are 0.52 and 0.75, so the concrete under inspection will not crack.

scholarly journals A Study on Relationship Between the Heat Release of Later-age Concrete and the Concrete Strength Development

2016 ◽  
Vol 10 (1) ◽  
pp. 363-368 ◽  
Author(s):  
Zhenyang Zhu ◽  
Weimin Chen ◽  
Zhiqiang Xie ◽  
Guoxin Zhang
Keyword(s):  
Heat Release ◽  
Temperature Rise ◽  
Concrete Strength ◽  
Adiabatic Temperature ◽  
Hydration Heat ◽  
Strength Development ◽  
Early Age ◽  
Testing Device ◽  
Adiabatic Temperature Rise ◽  
Early Age Concrete

The adiabatic temperature rise of early-age concrete can be precisely tested by the device. However, the insufficient accuracy of testing device can lead to inaccurate measurements of adiabatic temperature rise of later-age concrete. The purpose of this paper is to create a model to predict the hydration heat of later-age concrete. Based on the previous studies, it is known that the heat release of the concrete is accomplished with the increment of the concrete strength and concrete strength can be accurately measured. Thus, a preliminary later-age hydration heat model was established. The correction of the model was verified through experiments.

scholarly journals Effects of Steel Slag Powder and Expansive Agent on the Properties of Ultra-High Performance Concrete (UHPC): Based on a Case Study

Materials ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 683
Author(s):  
Shunkai Li ◽  
Shukai Cheng ◽  
Liwu Mo ◽  
Min Deng
Keyword(s):  
Temperature Rise ◽  
High Performance ◽  
High Performance Concrete ◽  
Steel Slag ◽  
Adiabatic Temperature ◽  
Hydration Heat ◽  
Ultra High Performance Concrete ◽  
Adiabatic Temperature Rise ◽  
Slag Powder ◽  
Steel Slag Powder

In view of the performance requirements of mass ultra-high performance concrete (UHPC) for the Pang Gong bridge steel cable tower in China, the UHPC incorporating of steel slag powder and hybrid expansive agents is optimized and prepared. The effects of steel slag powder and hybrid expansive agents on the hydration characteristics and persistent shrinkage of UHPC are investigated. The results indicate that 15 wt.% steel slag powder and 5 wt.% hybrid expansive agents can effectively reduce the drying shrinkage deformation of UHPC with a slight decrease of strength. Heat flow calorimetry results show that the incorporation of steel slag powder and expansive agents decreases the hydration heat at three days. Moreover, the obtained adiabatic temperature rise of UHPC is 59.5 °C and the total shrinkage value at 180 days is 286 με. The hydration heat release changes of large volume UHPC in the steel-concrete section of cable tower is agreed with the result of adiabatic temperature rise in the laboratory.

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