Numerical Simulation of Heat Evolution of Eco-Friendly Blended Portland Cements Using a Multi-Component Hydration Model

2008 ◽  
Vol 569 ◽  
pp. 257-260 ◽  
Author(s):  
Xiao Yong Wang ◽  
Han Seung Lee ◽  
Ki Bong Park
Keyword(s):  
Portland Cement ◽  
Pozzolanic Reaction ◽  
Heat Evolution ◽  
Curing Temperature ◽  
Evolution Process ◽  
Waste Materials ◽  
Portland Cements ◽  
Influence Of Water ◽  
Mineral Components ◽  
Hydration Model

With the development of concrete industry, the necessity for utilizing waste materials and decreasing overall energy consumption is becoming increasingly obvious. Fly ash and granulated blast-furnace slag, which are used as blends of Portland cement, are waste materials produced in electric and energy industry, and concretes made with them can have properties similar to ones made with pure Portland cement at lower cost per unit volume. By using blended Portland cement, both ecology benefit and economic benefit can be achieved. Due to the pozzolanic reaction between calcium hydroxide and blended components, compared with ordinary Portland cement, hydration process of blended Portland cement is more complex. In this paper, based on a multi-component hydration model, a numerical model which can simulate heat evolution process of blended Portland cements is built. The influence of water to cement ratio, curing temperature, particle size distribution of cement paste and blended Portland material, and cement mineral components on heat evolution process is considered. The prediction result agrees well with experiment result.

Numerical Simulation of Autogenous Shrinkage of Eco-Friendly Blended Portland Cements Using a Multi-Component Hydration Model

2008 ◽  
Vol 569 ◽  
pp. 261-264 ◽  
Author(s):  
Xiao Yong Wang ◽  
Han Seung Lee ◽  
Seung Min Lim
Keyword(s):  
Fly Ash ◽  
Portland Cement ◽  
Ordinary Portland Cement ◽  
Autogenous Shrinkage ◽  
Heat Of Hydration ◽  
Curing Temperature ◽  
Portland Cements ◽  
Influence Of Water ◽  
Hydration Model ◽  
Numerical Program

Fly ash and granulated blast-furnace slag, which are used as blends of Portland cement, are waste materials produced in electric and energy industry. Due to excellent durability, low heat of hydration, energy-saving, resource-conserving, and generally less expensive than ordinary Portland cement, blends Portland cements is used increasingly in construction industry. Both ecology benefit and economic benefit can be achieved by using blended Portland cement. Addition of blended components to cement, especially such as fly ash or silica fume, will lead to a densification of the microstructure. The autogenous shrinkage deformation will increase and the following autogenous shrinkage crack will do harm to durability of concrete structure. In this paper, based on the multi-component hydration model, a numerical program is built to predict autogenous shrinkage of ordinary Portland cement and blended Portland cement. The numerical program considers the influence of water to cement ratio, curing temperature, particle size distribution, cement mineral components on hydration process and autogenous shrinkage. The prediction result agrees well with experiment result.

Modeling of hydration reactions to predict the properties of slag blended concrete

2014 ◽  
Vol 41 (5) ◽  
pp. 421-431
Author(s):  
Xiao-Yong Wang ◽  
Ki-Bong Park
Keyword(s):  
Portland Cement ◽  
Cement Hydration ◽  
Blended Cement ◽  
Numerical Procedure ◽  
Reaction Model ◽  
Heat Evolution ◽  
Mineral Admixture ◽  
Temperature History ◽  
Granulated Blast Furnace Slag ◽  
Hydration Model

The granulated blast furnace slag is commonly blended with Portland cement or clinker to produce slag blended cement after being ground to the fineness comparable to Portland cement. Hydration of slag-blended cement is much more complex than that of ordinary Portland cement because of the mutual interactions between the cement hydration and the slag reaction. In this paper, by considering the production of calcium hydroxide in cement hydration and its consumption in the reaction of slag, a numerical procedure is proposed to simulate the hydration of concrete containing slag. The numerical procedure includes two sub components, a cement hydration model and a slag reaction model. The heat evolution rate of slag concrete is determined from the contributions of the cement hydration and the slag reaction. Furthermore, the temperature history in hardening blended concrete is evaluated by combining the proposed numerical procedure with a finite element method. The proposed model is verified through experimental data on concrete with different water–cement ratios and mineral admixture substitution ratios.

Prediction of the Carbonation Depth of Concrete with a Mortar Finish

2008 ◽  
Vol 385-387 ◽  
pp. 633-636 ◽  
Author(s):  
Han Seung Lee ◽  
Xiao Yong Wang
Keyword(s):  
Portland Cement ◽  
Numerical Procedure ◽  
Pozzolanic Reaction ◽  
Surface Coatings ◽  
Reinforced Concrete Structures ◽  
Hydration Products ◽  
Application Time ◽  
Carbonation Depth ◽  
Hydration Model ◽  
Corrosion Of Steel

It is well known that carbonation will result corrosion of steel reinforcement in reinforced concrete structures. To reduce the rate of carbonation, the surface coatings, such as mortar finish, has been used widely to concrete. This paper presents a numerical procedure about carbonation of the coating-concrete system. This numerical procedure starts with a multi-component hydration model. By hydration model which considers both and Portland cement and pozzolanic reaction, the amount of hydration products which are susceptible to carbonate as well as porosity is obtained as function of age. Furthermore, the diffusivity of CO2 is determined and carbonation depth of concrete is predicted. Parameter studies are performed to show the influence of composition and application time of mortar finish on carbonation depth of substrate concrete.

scholarly journals The Effect of Sodium Gluconate on Pastes’ Performance and Hydration Behavior of Ordinary Portland Cement

2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
Xingdong Lv ◽  
Jiazheng Li ◽  
Chao Lu ◽  
Zhanao Liu ◽  
Yaosheng Tan ◽  
...  
Keyword(s):  
Portland Cement ◽  
Ordinary Portland Cement ◽  
Cement Hydration ◽  
Isothermal Calorimetry ◽  
Setting Time ◽  
Heat Evolution ◽  
Curing Temperature ◽  
Sodium Gluconate ◽  
Early Hydration ◽  
Negative Effect

The goal of this paper provides better understanding of the effect of sodium gluconate (SG) on ordinary Portland cement (OPC) hydration behavior. Pastes’ performances of ordinary Portland cement, including setting time at 20°C and 35°C curing temperature, mechanical strength, fluidity, and zeta potential are studied. Furthermore, the effects of SG on cement hydration behaviors are investigated by the means of isothermal calorimetry measurements, X-ray diffraction (XRD), and thermogravimetric analysis (TGA). The results show that SG is difficult to maintain significant retarding effect at the temperature of 35°C compared to that at the temperature of 20°C. SG is able to reduce the cement cumulative hydration heat and delay the occurrence time of heat evolution peak in a certain extent, but it has little impact on reducing the cement evolution rate peak. The effects of SG on mechanical properties and dispersion properties of cement depend on its dosages. Specifically, the positive effect occurs when the addition dosage is less than 0.15% (i.e., by cement weight), but the negative effect emerges if the addition dosages exceed this limitation. Similarly, SG plays different roles on cement hydration at different hydration periods. It inhibits the hydration of C3S and the formation of portlandite (CH) at the early hydration period. On the contrary, it promotes the C3S hydration when hydration time is beyond 1 d. Meanwhile, SG also plays different roles on cement hydration at different dosage additions. Specifically, SG promotes ettringite (AFt) formation at the dosage less than 0.06%, but it inhibits AFt formation at the dosage more than 0.06%.

Mechanism of Cement Paste with Different Particle Sizes of Bottom Ash as Partial Replacement in Portland Cement

2017 ◽  
Vol 68 (10) ◽  
pp. 2367-2372 ◽  
Author(s):  
Ng Hooi Jun ◽  
Mirabela Georgiana Minciuna ◽  
Mohd Mustafa Al Bakri Abdullah ◽  
Tan Soo Jin ◽  
Andrei Victor Sandu ◽  
...  
Keyword(s):  
Portland Cement ◽  
Construction Material ◽  
Bottom Ash ◽  
High Volume ◽  
Cement Composite ◽  
Pozzolanic Reaction ◽  
High Specific Surface Area ◽  
Partial Replacement ◽  
Natural Aggregates ◽  
Pozzolanic Properties

Manufacturing of Portland cement consists of high volume of natural aggregates which depleted rapidly in today construction field. New substitutable material such as bottom ash replace and target for comparable properties with hydraulic or pozzolanic properties as Portland cement. This study investigates the replacement of different sizes of bottom ash into Portland cement by reducing the content of Portland cement and examined the mechanism between bottom ash (BA) and Portland cement. A cement composite developed by 10% replacement with 1, 7, 14, and 28 days of curing and exhibited excellent mechanical strength on day 28 (34.23 MPa) with 63 mm BA. The porous structure of BA results in lower density as the fineness particles size contains high specific surface area and consume high quantity of water. The morphology, mineralogical, and ternary phase analysis showed that pozzolanic reaction of bottom ash does not alter but complements and integrates the cement hydration process which facilitate effectively the potential of bottom ash to act as construction material.

Effect of W/B ratios on pozzolanic reaction of biomass ashes in Portland cement matrix

2012 ◽  
Vol 34 (1) ◽  
pp. 94-100 ◽  
Author(s):  
V. Sata ◽  
J. Tangpagasit ◽  
C. Jaturapitakkul ◽  
P. Chindaprasirt
Keyword(s):  
Portland Cement ◽  
Pozzolanic Reaction ◽  
Cement Matrix ◽  
Biomass Ashes

scholarly journals Development of Concrete Paving Blocks Prepared from Waste Materials without Portland Cement

2018 ◽  
Vol 24 (1) ◽  
Author(s):  
Charin NAMARAK ◽  
Chaiwut BUMRUNGSRI ◽  
Weerachart TANGCHIRAPAT ◽  
Chai JATURAPITAKKUL
Keyword(s):  
Portland Cement ◽  
Waste Materials

Calorimetric determination of the effect of additives on cement hydration process

2013 ◽  
Vol 67 (2) ◽  
Author(s):  
Pavel Šiler ◽  
Josef Krátký ◽  
Iva Kolářová ◽  
Jaromír Havlica ◽  
Jiří Brandštetr
Keyword(s):  
Portland Cement ◽  
Silica Fume ◽  
Maximum Temperature ◽  
Granulated Blast Furnace Slag ◽  
Mineral Components ◽  
Maximum Temperatures ◽  
The Impact ◽  
Furnace Slag ◽  
Calorimetric Determination

AbstractPossibilities of a multicell isoperibolic-semiadiabatic calorimeter application for the measurement of hydration heat and maximum temperature reached in mixtures of various compositions during their setting and early stages of hardening are presented. Measurements were aimed to determine the impact of selected components’ content on the course of ordinary Portland cement (OPC) hydration. The following components were selected for the determination of the hydration behaviour in mixtures: very finely ground granulated blast furnace slag (GBFS), silica fume (microsilica, SF), finely ground quartz sand (FGQ), and calcined bauxite (CB). A commercial polycarboxylate type superplasticizer was also added to the selected mixtures. All maximum temperatures measured for selected mineral components were lower than that reached for cement. The maximum temperature increased with the decreasing amount of components in the mixture for all components except for silica fume. For all components, except for CB, the values of total released heat were higher than those for pure Portland cement samples.

Low Cement/High Fly Ash Concretes: Their Properties and Response to Chemical Admixtures

1987 ◽  
Vol 113 ◽  
Author(s):  
V. H. Dodson
Keyword(s):  
Fly Ash ◽  
Portland Cement ◽  
Calcium Hydroxide ◽  
Pozzolanic Reaction ◽  
Portland Cement Concrete ◽  
Cement Concrete ◽  
Fly Ashes ◽  
Chemical Admixtures ◽  
Reaction With Water

ABSTRACTIn practice, the amount of fly ash added to portland cement concrete varies depending upon the desired end properties of the concrete. Generally, when a given portland cement concrete is redesigned to include fly ash, between 10 and 50% of the cement is replaced by a volume of fly ash equal to that of the cement. Sometimes as much as twice the volume of the cement replaced, although 45.4 kg (100 lbs) of cement will only produce enough calcium hydroxide during its reaction with water to react with about 9 kg (20 lbs) of a typical fly ash. The combination of large amounts of certain fly ashes with small amounts of portland cement in concrete has been found to produce surprisingly high compressive strengths, which cannot be accounted for by the conventional “pozzolanic reaction”. Ratios of cement to fly ash as high as 1:15 by weight can produce compressive strengths of 20.7 MPa (3,000 psi) at I day and over 41.4 MPa (6,000 psi) at 28 days. Methods of identifying these “hyperactive” fly ashes along with some of the startling results, with and without chemical admixtures are described.

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