Mechanical performance, hydration characteristics and microstructures
Han [42] showed that the hydration heat evolution rate was improved and the ending time of the induction period was shortened when the curing temperature was 60 ℃. In addition, the cumulative hydration heat gap between 70% BFFS and pure cement was decreased. Steam curing was verified an effective method to improve the early …
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What are the 5 Stages of Cement Hydration Process
Heat of Hydration. The reaction of cement and water is exothermic. This reaction releases a lot of heat. ... To prevent this flash, gypsum should be added when grinding cement clinker. The amount of gypsum added is related to the amount of C 3 A present. The hydrated aluminate does not contribute to the strength of concrete. On the other hand ...
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Predicting One-Day, Three-Day, and Seven-Day Heat of Hydration …
This paper aims to develop empirical equations predicting one-day, three-day, and seven-day heat of hydration of portland cement at 23°C and water to cement ratio of 0.5.
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Influence of grinding method and particle size distribution …
In the conventional process of cement production, 30–80 kWh/t specific energy is consumed in cement grinding which equals 30 % of the total energy consumption. Furthermore, approximately 60–70 % of the total electrical energy used in a cement plant is utilized for the grinding of raw materials, coal, and clinker.
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Effect of wet grinded lithium slag on compressive strength …
It was also reported that the paste with D50 was 0.3 μm could be obtained via wet grinding, and it could efficiently induce the early hydration of Portland cement by acting as nucleation seeds [28]. It was noted that the D50 of LS decrease from 3.04 μm to 300 nm resulted in the increase in dissolution of lithium from 3.94 mg/L to 24.1 mg/L [28] .
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Effects of carbonation degree on the hydration
The Blaine's fineness of both uncarbonated steel slag and steel slag with low carbonation degree after grinding were about 500 m 2 /kg, ... In order to further study the effects of carbonated steel slag on cement hydration, the chemically combined ... Until 72 h, the total heat of hydration with 5 wt% increased by 28.4 %, compared to that of ...
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The effect of wet-grinding phosphorus slag on the hydration …
Unlike the dry grinding of traditional cement, wet-grinding can treat the material under water conditions, which reduces the surface energy of the material and avoids the agglomeration of particles [24]. ... Hydration heat flow (a) and cumulative hydration heat (b) curves of paste samples for 120 h.
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Heat of hydration prediction for blended cements
The recommended strategies for reducing the amount of heat generated during cement hydration include the use of low-heat portland cements, blended …
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Advances in understanding hydration of Portland cement
Abstract. Progress in understanding hydration is summarized. Evidence supports the geochemistry dissolution theory as an explanation for the induction period, in preference to the inhibiting layer theory. The growth of C–S–H is the principal factor controlling the main heat evolution peak. Electron microscopy indicates that C–S–H ...
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Nano particles prepared from hardened cement paste by wet grinding …
Hydration heat of all samples was increased over time because of the continuous hydration of cement, but its incremental ratio was obviously weakened. For example, with the addition of 2% WGRP, the hydration heat of PC pastes was increased by 92% at 12 h age, but the increase ratio was just 11% at 3 d age. Download : …
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Heat of hydration and the importance of controlling it
Q. What is meant by heat of hydration and why is it sometimes important to control the heat generated in concrete? A. The reactions that bring about the hardening of hydraulic cement pastes are exothermic, that is, they are accompanied by the liberation of heat. This heat of hydration is an important factor in mass concrete (ACI 207.1R).
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Hydration Kinetics of Phosphorus Slag-cement Paste
There is a reduction of 25.3% and 18.6% in the cement hydration heat within 3 days and 180 days when 30 wt% FA is blended. ... wet-grinding enhanced the hydration degree and rate in the nucleation ...
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Unlocking the potential of ordinary Portland cement …
cement with hydration control additive enabling ... clinker during the grinding or sometimes the mixing process to ... heat flow during the first 0.5h from in situ calo, (b) heat flow during ...
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Heat of hydration and the importance of controlling it
This heat of hydration is an important factor in mass concrete (ACI 207.1R). Mass concrete as any volume of concrete with dimensions large enough to require that …
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Mutual compatibility of superplasticizers (PC, SNF), grinding …
Grinding aids increases the rate and the total heat of cement hydration. TEA accelerates the reaction, intensifies the aluminate peak and shortens the induction period more than glycol, as observed in the calorimetric curve. The flowability of low-C 3 A cement ground with GA was higher than that of high-C 3 A cement mortars.
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Effect of wet-grinding steel slag on the properties of Portland cement
The setting time, rheology, hydration heat, compressive strength, hydration products, microstructure and autogenous shrinkage of wet-grinding steel slag – cement composition were investigated in this study. Material Sustainability Indicator (MSIs) was used to analyse the impact of wet-grinding steel slag on environment to prove that wet ...
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Prediction of heat of hydration of cementitious systems
The temperature and time-dependent heat of hydration of cementitious pastes is a fundamental property to understand concrete performance. Cement hydration can be depicted using kinetic models by considering the effect of the chemical and physical properties of the cementitious pastes and the curing conditions. Supplementary …
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Heat of hydration prediction for blended cements
The wet grinding method was used to avoid the effect of temperature on gypsum and its possible phase transformation to hemihydrate or anhydrite. ... Kishi T, Maekawa K. Multi-component model for hydration heat of Portland cement. Concr Libr JSCE. 1996;28:97–115. Google Scholar
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Unlocking the potential of ordinary Portland cement with hydration …
Ordinary Portland cement (OPC) is the core ingredient of many construction materials. In 2022, 4.1 billion tons were used worldwide, contributing to ~8% of CO2 emissions ( ~ 3 Gt/year).
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Evaluation of heat of hydration, temperature …
Hydration of a greater amount of cement leads to a higher concrete temperature and a larger temperature difference between the middle and the outer …
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Improving durability of heat-cured high volume fly ash cement …
For high volume fly ash blended cement systems, the more fly ash is added per unit volume, the less cement is in the system, and the less water is consumed by the hydration reaction of cement. In other words, the effective water-to-cement ratio is higher in systems with higher fly ash content, although the total water-to-binder ratio is the same.
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(PDF) The Effect of Various Grinding Aids on the Properties of Cement …
production of Portland cement, grinding aids are added in small amounts in the range of 0.01 to 0.10% by weight of cement, according to the PN-EN 197-1 standard [ 1
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Advances in hydration and thermodynamics of
3.Early-age C 3 S/alite hydration. Today no one disputes that hydration is a dissolution-precipitation process. It is now clear that C-S-H precipitates very early during the hydration of C 3 S or alite, but that the rate of reaction then slows down dramatically leading to what is known as the induction period. At the end of the induction period the …
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(PDF) Mutual compatibility of superplasticizers …
of reaction, the hydration heat of cements ground with G and T was 14 – 18% higher for CL and 2 – 7% higher for CH, compared to the refer- ence samples without grinding aids.
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Heat-cured cement-based composites with wet-grinded fly …
And the higher the WCS content, the earlier the time of hydration heat release. Taking the WFA-cement binder with 12 wt% WCS for example, the location of the main hydration peak was advanced by 32.4%, from 24.7 h (F-0-50) to 16.7 h (F-12-50). ... due to the promoted Al incorporation in C-S-H by wet-grinding. (5) During the hydration …
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Evaluation of heat of hydration, temperature evolution and thermal
During the hydration, the rate of heat of hydration depends on temperature of the concrete. Higher temperature accelerates the rate of the cementitious material hydration reactions. Van Breugel [6] and Schindler and Folliard [7] reported that the cement degree of hydration was proportional to the heat released, as shown in Eq.
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Resistance to Grinding and Cement Paste Performance of
Regression models were obtained using R version 3.5.1 for: (i) the resistance to grinding (K R), (ii) the 28-day compressive strength and (iii) the point of maximum heat liberation during the accelerating period of cement hydration. The independent variables in the models were the volumetric fractions of the raw materials in the blend.
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Improving durability of heat-cured high volume fly ash cement …
This work investigated the durability performances of heat-cured high volume (30 wt%–70 wt%) fly ash (FA) cement mortars by using different particle sizes (19.7 μm, 4.29 μm and 2.51 μm) and ...
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Cement hydration kinetics study in the temperature
The heat evolution during the hydration of cement was examined by multiple calorimetric methods: isothermal, oscillating isothermal, as well as temperature scanning tests in the temperature range from 15 °C to 95 °C. The apparent activation energy ( Ea) of several different types of cements were all found to decrease significantly with ...
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Standard Test Method for Heat of Hydration of …
solution of the dry cement and the heat of solution of a separate portion of the cement that has been partially hydrated for 7 and for 28 days, the difference between these values being the heat of hydration for the respective hydrating period. 1.2 The results of this test method may be inaccurate if some of the components of the hydraulic ...
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