scholarly journals Application of hydration heat inhibitor in crack control of mass concrete of tunnel side wall

2021 ◽  
Vol 283 ◽  
pp. 01032
Author(s):  
XiZhi Wang ◽  
MinSheng Shi ◽  
XinGang Wang
Keyword(s):  
Temperature Rise ◽  
Concrete Strength ◽  
Side Wall ◽  
Hydration Heat ◽  
Structural Deformation ◽  
Maximum Temperature ◽  
Optimal Dosage ◽  
Mass Concrete ◽  
Control Effect ◽  
Crack Control

The structural deformation caused by temperature change is the main reason for cracking of mass concrete. In order to avoid or reduce the crack of the side wall of cast-in-place mass concrete in tunnel, the effects of different dosage of hydration heat inhibitor on the internal temperature rise curve of concrete, strength and the properties of the mixture are analyzed through experimental research, and the optimal dosage of 1% of cementing material is finally determined. The engineering application results show that after adding hydration heat inhibitor to the tunnel side wall concrete, the maximum temperature rise in the tunnel side wall is obviously reduced, and the arrival time of the temperature peak is delayed. No cracks appear in the tunnel side wall, and the crack control effect is good.

scholarly journals Revisiting the Effect of Slag in Reducing Heat of Hydration in Concrete in Comparison to Other Supplementary Cementitious Materials

Materials ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 1847 ◽  
Author(s):  
Hoon Moon ◽  
Sivakumar Ramanathan ◽  
Prannoy Suraneni ◽  
Chang-Seon Shon ◽  
Chang-Joon Lee ◽  
...  
Keyword(s):  
Blast Furnace ◽  
Temperature Rise ◽  
Adiabatic Calorimetry ◽  
Blast Furnace Slag ◽  
Isothermal Calorimetry ◽  
Heat Of Hydration ◽  
Supplementary Cementitious Materials ◽  
Maximum Temperature ◽  
Mass Concrete ◽  
Furnace Slag

Blast furnace slag (SL) is an amorphous calcium aluminosilicate material that exhibits both pozzolanic and latent hydraulic activities. It has been successfully used to reduce the heat of hydration in mass concrete. However, SL currently available in the market generally experiences pre-treatment to increase its reactivity to be closer to that of portland cement. Therefore, using such pre-treated SL may not be applicable for reducing the heat of hydration in mass concrete. In this work, the adiabatic and semi-adiabatic temperature rise of concretes with 20% and 40% SL (mass replacement of cement) containing calcium sulfate were investigated. Isothermal calorimetry and thermal analysis (TGA) were used to study the hydration kinetics of cement paste at 23 and 50 °C. Results were compared with those with control cement and 20% replacements of silica fume, fly ash, and metakaolin. Results obtained from adiabatic calorimetry and isothermal calorimetry testing showed that the concrete with SL had somewhat higher maximum temperature rise and heat release compared to other materials, regardless of SL replacement levels. However, there was a delay in time to reach maximum temperature with increasing SL replacement level. At 50 °C, a significant acceleration was observed for SL, which is more likely related to the pozzolanic reaction than the hydraulic reaction. Semi-adiabatic calorimetry did not show a greater temperature rise for the SL compared to other materials; the differences in results between semi-adiabatic and adiabatic calorimetry are important and should be noted. Based on these results, it is concluded that the use of blast furnace slag should be carefully considered if used for mass concrete applications.

The Arch Support Construction and Hydration Heat Analysis of the First Bridge over Yangtze River in Hejiang

2013 ◽  
Vol 291-294 ◽  
pp. 1122-1127
Author(s):  
Yan Feng Luo ◽  
Da Yan Qin ◽  
Yun Zhang
Keyword(s):  
Yangtze River ◽  
Casting Process ◽  
Hydration Heat ◽  
Maximum Temperature ◽  
Mass Concrete ◽  
Element Analysis ◽  
Early Hydration ◽  
Mix Proportion ◽  
Arch Support ◽  
Heat Preservation

The arch support of the First Bridge over Yangtze River in Hejiang used the stratified and graded casting process in mass concrete pouring process. By means of optimizing the concrete mix proportion design, using high mixing amount of fly ash concrete, reducing heat release rate of concrete early hydration heat, delaying the time of maximum temperature rise, and combining turn-over forms and water storage and other surface heat preservation measures, the temperature difference between inside and outside concrete was reduced and the cracking of mass concrete was avoided. Finite element analysis of hydration heat was done to verify the feasibility of the construction scheme.

Non-Structural Cracking Analysis of early Age of Reinforcement Concrete Wall

2012 ◽  
Vol 446-449 ◽  
pp. 251-259
Author(s):  
Ting Yao ◽  
Jian Ye Zhang ◽  
Jia Ping Liu ◽  
Qian Tian
Keyword(s):  
Structural Engineering ◽  
Maximum Temperature ◽  
Early Age ◽  
Mass Concrete ◽  
Concrete Wall ◽  
Crack Control ◽  
Leading Role ◽  
Real Behavior ◽  
Unique Source ◽  
Source Of Information

Structure monitoring has been increasingly valuable in recent years and has taken a leading role in the field of structural engineering. Date collected by early age monitoring represent a unique source of information for understanding the real behavior. In this paper, the temperatures evolution and concrete deformation evolution are obtained by real-time continuous monitoring of Reinforcement concrete(RC) wall. The result shows that the early age thermal cracking is one of the most important origin of several phenomena that imperil durability and shorten the lifespan of the structure. Though the wall is not considered as mass concrete, and has a big radiating surface, the maximum temperature can even reach up to 52°C due to heat generation of cement and the insulation of formwork, which can lead to shrinkage deformation when the temperature decreases. The measured experimental date can provide useful reference for early crack control and durability of RC concrete structure, and they can also be use to verify and improve the accuracy of the numerical results for RC wall, which is available in the future for basis to similar projects and research.

Crack Control Technology for Concrete of Super-Large Section Precast Immersed Tube

2014 ◽  
Vol 578-579 ◽  
pp. 1240-1246
Author(s):  
Jin Hui Li ◽  
Ke Xin Liu ◽  
Liu Qing Tu ◽  
Yun Pang Jiao
Keyword(s):  
Temperature Control ◽  
Raw Materials ◽  
Concrete Strength ◽  
Complex Structure ◽  
Cooling Water ◽  
Temperature Monitoring ◽  
Raw Material ◽  
Maximum Temperature ◽  
Large Section ◽  
Crack Control

As the complex structure, large size, hot climate, aggressive corrosive environment and high concrete strength grade for Super-large Section Precast Immersed Tube of Hong Kong-Zhuhai-Macao Bridge, crack control of concrete was difficult. On the basis of simulating analysis on thermal stress, temperature control design was carried out. Harmful crack could be effective controlled by series of treatment measures during construction period such as optimization of raw materials, preparation of low heat and shrinkage concrete, controlling concrete raw material temperature, mixing concrete with ice shavings and cooling water, setting up automatic maintenance system and automatic temperature monitoring system. From the monitoring results, the temperature monitoring results were consistent with the simulation data, and the maximum temperature and the temperature difference between concrete surface and internal concrete were met the requirement of temperature control standard. Moreover, the precast immersed tube didn’t appear harmful crack.

Mass concrete sections and the maturity concept

1976 ◽  
Vol 3 (1) ◽  
pp. 47-57 ◽  
Author(s):  
E. G. Nisbet ◽  
S. T. Maitland
Keyword(s):  
Temperature Rise ◽  
Concrete Strength ◽  
Temperature Curve ◽  
Mass Concrete ◽  
Structural Elements ◽  
Standard Laboratory ◽  
Laboratory Conditions ◽  
Concrete Cylinders ◽  
Recording Potentiometer ◽  
Early Strength

The 28 day strength of concrete cylinders cured under standard laboratory conditions can now be reliably predicted at early ages by use of (a) the Modified Boiling Test or (b) the Autogenous Curing Test. The availability of early strength indicators for concrete can be used to great advantage during construction provided these strengths can be related to the strength of the structural elements.To permit an estimate to be made of the strength of in-place concrete on structures appurtenant to the Welland Channel By-pass, the temperature rise of the structural elements was monitored with an automatic 16 point recording potentiometer. The time temperature curve of the in-place concrete was compared to that of 6 in. by 12 in. (150 mm by 300 mm) concrete cylinders taken during casting of the structure and cured autogenously for 48 h, thus permitting an estimate of the in-place concrete strength to be made from the results of the 48 h autogenous strengths.On the basis of the in-place concrete strength estimates, decisions were made regarding the application of post tensioning forces and/or the removal of formwork and supporting shoring.

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.

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.

Modelling the early age behaviour of a low heat concrete bulkhead sealing an underground tunnel

2000 ◽  
Vol 27 (1) ◽  
pp. 112-125 ◽  
Author(s):  
Olivier Didry ◽  
Malcolm N Gray ◽  
André Cournut ◽  
James Graham
Keyword(s):  
Numerical Model ◽  
Temperature Rise ◽  
Numerical Models ◽  
Autogenous Shrinkage ◽  
Heat Of Hydration ◽  
High Mass ◽  
Maximum Temperature ◽  
Early Age ◽  
Mass Concrete ◽  
Government Organizations

A major experiment - the tunnel sealing experiment, related to the disposal of heat generating radioactive wastes in geological formations and supported by government organizations from Japan, France, U.S.A., and Canada, is being carried out at the Underground Research Laboratory of Atomic Energy of Canada Limited in Manitoba, Canada. Through a systematic process, the results from the experiment will be used to validate numerical models for the early age behaviour of high mass concrete bulkheads. A numerical model, based on the CESAR-LCPC finite element code equipped with the modules TEXO and MEXO, has been developed and used to predict the behaviour of a concrete bulkhead which will be built as part of the experiment. The TEXO-based component of the model which describes temperature changes has been validated. A maximum temperature rise in the concrete of 19°C is calculated. This will occur about 4 days after the concrete is cast. The temperature rise is low. This arises from the use of a specially developed low cement content concrete. Despite uncertainties in the MEXO-based model, which is used to describe the chemo-mechanical behaviour of the system, results indicate that it is unlikely that the concrete will crack, but a gap of 0.5 mm or more will develop between the bulkhead and the rock. Water leakage around the bulkhead through this gap could be significant and measures to seal this gap are advised. The modelling results recorded here will be tested against measurements made in the experiment. Thus, the numerical model will be formally validated and bounds to its use will be defined. Key words: concrete, bulkhead, sealing, early age behaviour, heat of hydration, autogenous shrinkage, underground repository, modelling.

scholarly journals Application of HCSA expansive agent in crack control of mass concrete

2021 ◽  
Vol 283 ◽  
pp. 01011
Author(s):  
XinGang Wang ◽  
ShiGuang Fan
Keyword(s):  
Vertical Direction ◽  
Side Wall ◽  
Shrinkage Strain ◽  
Bottom Plate ◽  
Time Interval ◽  
Mass Concrete ◽  
Crack Control ◽  
Expansive Agent ◽  
Long Time ◽  
Expansion Effect

The open section of the west artificial island of the Hong Kong-Zhuhai-Macao Bridge is a mass concrete structure. The concrete was poured in two times in the vertical direction, that is, the whole bottom plate was poured in the first time, and the middle wall and two side walls were poured in the second time. The side wall and middle wall are easy to crack due to the long time interval between two concrete castings. In order to study the function and effect of HCSA expansion agent in the crack control of mass concrete, the applicable condition of compensating shrinkage in the crack control of mass concrete is analyzed first. Then the effect of HCSA expansion agent was studied in laboratory and field. The experimental results show that HCSA expander has a good expansion effect under laboratory conditions, but it has no expansion effect on the middle side of the mass concrete test block in the engineering site, instead, it will further increase the internal temperature rise of concrete and increase the shrinkage strain of concrete. HCSA expander is helpless for crack control of mass concrete.

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