Multi-Component Model for Hydration Heat of Portland Cement

Kishi, Toshiharu; Maekawa, Koichi

doi:10.2208/jscej.1995.526_97

Cited by 44 publications

(37 citation statements)

References 3 publications

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“…In this paper, a multi-component hydration heat model developed by Kishi (1994Kishi ( , 1995Kishi ( , 1996Kishi ( , 1997 and Maekawa et al (2008) is investigated. In this model, hydration and heat generation of components in cement including clinkers such as C 3 S, C 2 S, C 3 A, C 4 AF, and mineral admixtures such as fly ash and blast furnace slag are treated respectively by the Arrhenius law of chemical reaction and then integrated together.…”

Section: Introductionmentioning

confidence: 99%

Enhanced Model and Simulation of Hydration Process of Blast Furnace Slag in Blended Cement

Luan

Ishida

Nawa

et al. 2012

ACT

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Analytical hydration model for filler rich self-compacting concrete AbstractA hydration model for cementitious materials was applied to slag blended cement. The original model was found to overestimate the hydration degree of slag, and the influence of the slag ratio on the hydration degree not to be well simulated either. The hydration mechanism of slag was investigated, considering the role of calcium hydroxide as activator and the Ca/Si ratio of C-S-H. It is assumed that for low Ca/Si ratio, the C-S-H inner product has a stronger resistance against ion diffusion and thus influences the hydration process significantly. Accordingly an enhanced model for slag hydration is proposed. Finally, the enhanced model is verified by both hydration degree and heat generation tests.

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Section: Introductionmentioning

confidence: 99%

Enhanced Model and Simulation of Hydration Process of Blast Furnace Slag in Blended Cement

Luan

Ishida

Nawa

et al. 2012

ACT

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“…This especially holds in the period of formation of the hydration shell, since the precipitation process controls the rate of hydration during that period. This has been suggested by existing experimental data and hydration models (Taplin 1959;Kishi and Maekawa 1995;van Breugel 1995avan Breugel , 1995b. Therefore, the rate of hydration is modeled as a function of water content using the factor γ w .…”

Section: Rate Of Hydrationmentioning

confidence: 99%

“…Three different temperature conditions at a fresh state were assumed. The experimental data were obtained from Kishi and Maekawa (1995). ( ) ( )…”

Section: Moisture Transport and Water Vapor Sorptionmentioning

confidence: 99%

Numerical Approach towards Aging Management of Concrete Structures: Material Strength Evaluation in a Massive Concrete Structure under One-Sided Heating

Maruyama

Igarashi

2015

ACT

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For the purpose of performance evaluation of an existing reinforced concrete member, a chemo-thermo-hygro model to predict the spatial and temporal changes of physical properties of concrete in the member, named the "Computational Cement-Based Material Model (CCBM)", was proposed. This proposed simulation model includes models of rate of hydration of cement minerals, phase composition, and resultant properties of cement paste (i.e., compressive strength, Young's modulus, Poisson's ratio, thermal expansion coefficient, autogenous shrinkage, drying shrinkage, heat capacity, heat transfer coefficient, water vapor sorption isotherms, and water transfer coefficient). Furthermore, the model for compressive strength of concrete considered the variation in cement paste strength due to its colloidal features as well as micro-defects produced around aggregate due to differences in volume between aggregates and mortar upon heating and drying. The concrete properties of spatial distribution and temporal changes were evaluated by coupling these models with heat and water transport. Validation of these models was achieved by using existing experimental data. Using this CCBM, a thick concrete wall made with moderate Portland cement with a water-to-cement ratio of 0.55 under one-sided heating was simulated and potential problems that can arise during an integrity evaluation were discussed. If the required compressive strength, which was assessed within 91 days of placement, remains unchanged, an additional hydration process can build an adequate strength margin to overcome the risk of strength reduction due to heat and drying. However, in the case that the required strength is increased due to a re-evaluated risk, such as the magnitude of an earthquake, performance evaluation is not trivial as the core sample taken from the side where the execution of sampling is possible could exhibit a greater strength than the average strength of the target concrete member. Therefore, numerical evaluation might aid in this kind of situation.

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“…The inputs required in this scheme are mix proportion, powder material characteristics, casting temperature, geometry of the target structure, and the boundary conditions to which the structure will be exposed during its life-cycle. Using the multi-component hydration model, solutions for temperature, degree of hydration, and amount of chemically combined water are obtained [4][5]. By applying the average level of hydration and chemically combined water to a micro pore structure development model, the porosity distribution of hydrated and non-hydrated compounds around reference cement particles is calculated and the surface area of the micro-pores is estimated mathematically [2].…”

Section: Outline Of Fe Programsmentioning

confidence: 99%

An Integrated Computational System of Mass/Energy Generation, Transport and Mechanics of Materials and Structures

Ishida¹,

Maekawa²

1999

Doboku Gakkai Ronbunshu

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The authors present an integrated computational system consisting of a 3D FE structural analysis program and a 3D FE thermo-hygro physical analysis system which can model the development and deterioration of concrete materials performance. The thermo-dynamic process provides solutions for temperature, pore pressure, pore distributions, and other material properties in both 3D space and time. By passing this information to the structural mechanics process, the stress and damage to RC members caused by temperature changes and shrinkage can be obtained. The generation of cracks changes the material properties of mass transport, which are controlled by thermo-physics. This proposed integrated system can be used for the simultaneous evaluation of overall structural and material performances without distinguishing between structure and durability.

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Multi-Component Model for Hydration Heat of Portland Cement

Cited by 44 publications

References 3 publications

Enhanced Model and Simulation of Hydration Process of Blast Furnace Slag in Blended Cement

Enhanced Model and Simulation of Hydration Process of Blast Furnace Slag in Blended Cement

Numerical Approach towards Aging Management of Concrete Structures: Material Strength Evaluation in a Massive Concrete Structure under One-Sided Heating

An Integrated Computational System of Mass/Energy Generation, Transport and Mechanics of Materials and Structures

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