scholarly journals Partially Replacing Fly Ash with Limestone Powder in the Paste - Influence and Characterization

2015 ◽  
Vol 9 (1) ◽  
pp. 21-26 ◽  
Author(s):  
Lv Wenyu ◽  
Zhang Zhihui
Keyword(s):  
Shear Strength ◽  
Fly Ash ◽  
Temperature Rise ◽  
Frost Resistance ◽  
Setting Time ◽  
Research Direction ◽  
Adiabatic Temperature ◽  
Limestone Powder ◽  
Adiabatic Temperature Rise ◽  
Dry Shrinkage

Paste filling is an important research direction of coalmine “green mining” which can dispose coalmines solid waste and achieve environmental protection. The mechanical properties such as compressive strength, workability, ultimate tension value, shear strength and splitting strength of paste, in which the fly ash was partially replaced by limestone powder, was studied. Adiabatic temperature rise, setting time, shear strength, permeability, frost resistance and dry shrinkage of different substitution rate were investigated and the results were compared with traditional paste. The test results showed that the influence of limestone powder on workability, permeability and frost resistance performance of paste was slight, the setting time of paste were shortened, adiabatic temperature rise and mechanics performance of paste were decreased, dry shrinkage value was increased with limestone powder content increasing.

Influence of the Fly-Ash Content of Concrete at Low Water-Binder Ratio on Hydration Degree of Binders and Cement

2011 ◽  
Vol 250-253 ◽  
pp. 445-449
Author(s):  
Li Wei Xu ◽  
Jian Lan Zheng
Keyword(s):  
Fly Ash ◽  
Temperature Rise ◽  
High Performance Concrete ◽  
Ash Content ◽  
Adiabatic Temperature ◽  
Mineral Admixture ◽  
Hydration Degree ◽  
Adiabatic Temperature Rise ◽  
Binder Ratio ◽  
Water Binder Ratio

The hydration degree of binders and cement is investigated by measuring the adiabatic- temperature rise of concrete at low water-binder ratio with different fly-ash content. The results denote that, with a constant water-binder ratio, both of the hydration degree of binders and that of cement decrease with the increasing fly-ash content in the early stage. In a later stage, however, the hydration degree of cement increases with the increasing fly-ash content and the hydration degree of binders peaks when the fly-ash content is 35%. Fly ash is one of the mineral admixture of which high-performance concrete is made up. It brings down the rise of concrete temperature significantly and helps solve the problems of shrinkage and crack of concrete structure. Because the hydration mechanism in common concrete is different from that in concrete with low water-binder ratio, and the hydration environment is different between concrete and cement pastes, to determine the adiabatic-temperature rise of concrete directly conforms to the actual situation. The adiabatic-temperature rise, adiabatic-temperature-rise rate, hydration degree of both binders and cement are investigated by measuring adiabatic-temperature rise of concrete with different fly-ash content.

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.

A Study on the Influence of Fly Ash on the Thermal Parameters of Shrinkage Compensating Concrete

2018 ◽  
Vol 768 ◽  
pp. 336-340
Author(s):  
Yu Chuan Jiang ◽  
Je Xu ◽  
Bao Cheng Zhao ◽  
Yang Wang
Keyword(s):  
Thermal Conductivity ◽  
Fly Ash ◽  
Thermal Diffusivity ◽  
Specific Heat ◽  
Significant Influence ◽  
Temperature Rise ◽  
Thermal Parameters ◽  
Adiabatic Temperature ◽  
Adiabatic Temperature Rise ◽  
Air Content

This paper studies the adiabatic temperature rise, specific heat, thermal conductivity and thermal diffusivity of shrinkage compensating concrete mixed with 18%, 23%, 30% and 40% fly ash. The results present that fly ash has significant influence on the process of the adiabatic temperature rise, and the influence on the specific heat is little. The adiabatic temperature rise of 14d will be lower as the fly ash content is higher. There is significant influence of air content on thermal conductivity and thermal diffusivity, and the fly ash is little. Further research on the thermal parameters of shrinkage compensating concrete is needed.

Effect of Slag Characteristics on Adiabatic Temperature Rise of Blended Concrete

2022 ◽  
Author(s):  
Hai Zhu ◽  
Dhanushika Gunatilake Mapa ◽  
Catherine Lucero ◽  
Kyle A. Riding ◽  
A. Zayed
Keyword(s):  
Temperature Rise ◽  
Adiabatic Temperature ◽  
Adiabatic Temperature Rise

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.

scholarly journals Convenient Evaluation Method of Adiabatic Temperature Rise using Mortar Sample

2010 ◽  
Vol 48 (12) ◽  
pp. 15-22
Author(s):  
E. Maruya ◽  
H. Misumi ◽  
T. Takahashi ◽  
E. Sakai
Keyword(s):  
Temperature Rise ◽  
Evaluation Method ◽  
Adiabatic Temperature ◽  
Mortar Sample ◽  
Adiabatic Temperature Rise

scholarly journals Strength Development and Thermogravimetric Investigation of High-Volume Fly Ash Binders

Materials ◽  
2019 ◽  
Vol 12 (20) ◽  
pp. 3344 ◽  
Author(s):  
Zhiyuan Zhou ◽  
Massoud Sofi ◽  
Elisa Lumantarna ◽  
Rackel San Nicolas ◽  
Gideon Hadi Kusuma ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Temperature Rise ◽  
Bound Water ◽  
High Volume ◽  
Heat Of Hydration ◽  
New Method ◽  
Hydration Properties ◽  
Adiabatic Temperature Rise ◽  
High Volume Fly Ash

To address sustainability issues by facilitating the use of high-volume fly ash (HVFA) concrete in industry, this paper investigates the early age hydration properties of HVFA binders in concrete and the correlation between hydration properties and compressive strengths of the cement pastes. A new method of calculating the chemically bound water of HVFA binders was used and validated. Fly ash (FA) types used in this study were sourced from Indonesia and Australia for comparison. The water to binder (w/b) ratio was 0.4 and FA replacement levels were 40%, 50% and 60% by weight. Isothermal calorimetry tests were conducted to study the heat of hydration which was further converted to the adiabatic temperature rise. Thermo-gravimetric analysis (TGA) was employed to explore the chemically bound water (WB) of the binders. The results showed that Australian FA pastes had higher heat of hydration, adiabatic temperature rise, WB and compressive strength compared to Indonesian FA pastes. The new method of calculating chemically bound water can be successfully applied to HVFA binders. Linear correlation could be found between the WB and compressive strength.

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