The mechanism of the hydration in the system C3S-pozzolana

Ogawa, Kenji; Uchikawa, Hiroshi; Takemoto, Kunihiro; Yasui, Itaru

doi:10.1016/0008-8846(80)90032-0

Cited by 140 publications

(42 citation statements)

References 9 publications

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“…The observed accelerating effect has most often been attributed to additional nucleation of the hydration product stimulated by the surface of the silica additive. 44,46,47 In view of the significant accelerating effect of C-S-H reported here, we hypothesize that the nucleating agent is not the silica surface itself but rather the pozzolanic C-S-H that forms near this surface. Because the pozzolanic reaction with silica fume is relatively slow, additional nucleation sites are added gradually over the course of the early hydration period rather than all at once at the time of mixing.…”

mentioning

confidence: 77%

Influence of Nucleation Seeding on the Hydration Mechanisms of Tricalcium Silicate and Cement

2009

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The fundamental chemical hydration process of portland cement and its main mineral component, tricalcium silicate, was studied by investigating the effects of various additives. A relatively small amount (1-4 wt %) of well-dispersed calcium silicate hydrate (C-S-H), a pure form of the main hydration product, significantly increases both the early hydration rate and the total amount of hydration during the early nucleation and growth period (the first ∼24 h), as measured by calorimetry. This is attributed to a seeding effect whereby the C-S-H additive provides new nucleation sites within the pore space away from the particle surfaces. This mechanism is verified by a digital simulation of the hydration process that reproduces key features of the hydration kinetics. The results provide strong evidence that the hydration process is autocatalytic such that the C-S-H gel product stimulates its own formation. The seeding effect of C-S-H also provides a new explanation of the hydration-accelerating effects of various forms of reactive silica because these additives form C-S-H by reacting with aqueous calcium ions released by cement dissolution. Experiments involving sucrose, a hydration retarder, confirm that sucrose interferes with the normal nucleation process on the particle surface.

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mentioning

confidence: 77%

Influence of Nucleation Seeding on the Hydration Mechanisms of Tricalcium Silicate and Cement

2009

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“…In the case of OPC-BFS and OPC-BFS-LSP, except for the data of OPC-BFS-LSP at 28 days that can be judged as an experimental error, the hydration ratios are higher than OPC at every age, which indicates that BFS accelerates the hydration of C 3 S. Ogawa et al (1980) reported that BFS accelerates the hydration of C 3 S based on the hydration analysis of the C 3 S-BFS system using synthesized C 3 S from reagents. This result agrees with the results obtained in this study.…”

Section: Hydration Reaction Of Calcium Silicates and Bfsmentioning

confidence: 89%

“…BFS is reported to accelerate the hydration of C 3 S (Ogawa et al 1980, Uchikawa 1986, Imoto et al 2001, to delay the hydration of C 3 A estimated from the analysis of C 3 A-mellilite glass system (Hanada and Ito 1969), and to delay the hydration of C 4 AF at an early age estimated from the analysis of the C 4 AF-BFS system (Asaga and Kuga 1996). However, studies on the hydration analysis of BFS blended cement have been very limited.…”

Section: Introductionmentioning

confidence: 99%

XRD/Rietveld Analysis of the Hydration and Strength Development of Slag and Limestone Blended Cement

Hoshino¹,

Yamada²,

Hirao³

2006

ACT

120

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The X-ray diffraction (XRD)/Rietveld method was applied to analyze the hydration progress of cement paste prepared with blast furnace slag powder (BFS) and limestone powder (LSP). The Rietveld method can be used to quantify the amount of amorphous phase as well as crystalline phases. However, in cement paste containing BFS, two kinds of amorphous phases, unhydrated BFS and C-S-H, are included and the Rietveld method cannot distinguish them. In order to discriminate these two phases, a selective dissolution method was used to quantify the amount of unhydrated BFS. By combining these two methods, it became possible to quantify the amount of BFS and C-S-H in hydrated cement. The analysis results show that BFS accelerates the hydration of C 3 S, C 3 A, and especially C 4 AF. The strength increasing effect of LSP is more pronounced in the ordinary Portland cement (OPC) -BFS system than in the OPC system. This is attributed to the higher amount of calcium aluminate hydrates generated in the BFS contained system compared to the system without BFS. The additional calcium aluminate hydrates fill pores as calcium carboxaluminate by the reaction with LSP, increasing the compressive strength. These results show the effectiveness of the XRD/Rietveld method as an analysis tool for cement hydration relating to various properties of cement materials.

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“…In most cases, GGBS can quickly react with Ca(OH) 2 and generate the C-S-H gel, while the reaction between FA and portlandite is relatively slower. It is suggested that the fly ash surface acts as a Ca 2+ sink, which is caused by the reaction of the aluminate in the fly ash with the Ca from the solution and/or chemisorption of Ca 2+ ions on the fly ash surface [23,65]. This would retard the formation of C-S-H nuclei and thereby delay the end of the induction period.…”

Section: Hydration Kinetics Of the Designed Uhpcmentioning

confidence: 99%

Development of an eco-friendly Ultra-High Performance Concrete (UHPC) with efficient cement and mineral admixtures uses

Spiesz

Brouwers

2015

Cement and Concrete Composites

500

142

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The mechanism of the hydration in the system C3S-pozzolana

Cited by 140 publications

References 9 publications

Influence of Nucleation Seeding on the Hydration Mechanisms of Tricalcium Silicate and Cement

Influence of Nucleation Seeding on the Hydration Mechanisms of Tricalcium Silicate and Cement

XRD/Rietveld Analysis of the Hydration and Strength Development of Slag and Limestone Blended Cement

Development of an eco-friendly Ultra-High Performance Concrete (UHPC) with efficient cement and mineral admixtures uses

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