Influence of a C12A7 mineral-based accelerator on the strength and durability of shotcrete

Park, Hae-Geun; Sung, Sang-Kyoung; Park, Chan-Gi; Won, Jong-Pil

doi:10.1016/j.cemconres.2007.09.016

Cited by 74 publications

(28 citation statements)

References 6 publications

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“…In previous studies [11,12,13], it has been pointed out that the optimum dosage of C 12 A 7 -based accelerator locates in the range from 5% to 8%. Though a higher dosage of C 12 A 7 -based accelerator may leads to faster setting and hardening abilities of cement pastes or mortars, their mechanical properties may also be affected.…”

Section: Methodsmentioning

confidence: 99%

“…Park et al [11] proved that compared with other silicate- or aluminate-based accelerators, like C 12 A 7 , CaF 2 and C 4 A 3 s, the demand of C 12 A 7 -based accelerators was least, while the relevant groups had the fastest setting capacity, best mechanical properties, lowest chloride ion permeability, strongest freezing-thawing resistance and smallest strength decrease. Won et al [12] developed a new type of C 12 A 7 -based accelerator, and the mechanical strength of shotcrete with this accelerator was much high than that of shotcrete with the existing C 12 A 7 -based accelerator.…”

Section: Introductionmentioning

confidence: 99%

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The Influence of Mayenite Employed as a Functional Component on Hydration Properties of Ordinary Portland Cement

2018

Materials

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Influence of C12A7 (12CaO·7Al2O3) as a functional component on hydration properties of Ordinary Portland Cement is studied using isothermal microcalorimetric technique, X-ray diffraction analysis, and thermodynamic calculation. Meanwhile, hydrate assemblages are simulated by hydrothermal software. C2AH8 (2CaO·Al2O3·8H2O) is generated as a transition phase during the hydration of pure C12A7, while formation of CAH10 (CaO·Al2O3·10H2O) is uncertain. Heat-releasing behavior of Ordinary Portland Cement (OPC) could be noticeably affected by C12A7, especially for the duration of interaction at boundary stage reduces with C12A7 replacement. Correspondingly, all hydration kinetic parameters first increase and then diminish with C12A7 replacement. Simulation results manifest in the main hydration products of OPC being ettringite, C-S-H (Calcium-Silicate-Hydrate) gel, portlandite and brucite. Increasing C12A7 replacement accelerates the consumption rates of gypsum and calcite that are typically included in OPC, and thus the ettringite content is changed and carbonate phases will be produced. Therefore, the microstructure properties of hydrated products of OPC are affected and the compressive strength is influenced. These predications are in good agreement with experimental findings. C12A7 can be used as a functional component to adjust the consumption rate of suphates in OPC, and also components of carbonate phases can be modified in hydrate assemblage.

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

The Influence of Mayenite Employed as a Functional Component on Hydration Properties of Ordinary Portland Cement

2018

Materials

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“…In particular, they provide excellent quick-setting characteristics and the development of stable strength, as well as increased long-term strength for no increase in the cement volume. Of the numerous mineral-based accelerators, such as C 12 A 7 , C 11 A 7 , CaF 2 , and C 4 A 3 S, that are widely used, the C 12 A 7 -based accelerator is the most efficiency (Park et al, 2008;Ukrainczyk and Matusinovic, 2010).…”

Section: Methodsmentioning

confidence: 99%

Control of response time of early-stage concrete with accelerator using granulation processing

Lee¹,

Ryou²

2015

Magazine of Concrete Research

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Although accelerators can be used to prevent early frost damage by developing the strength of concrete in cold weather, they do not lead to retention of workability because early hydration makes them react rapidly. In this study, granulation was used as a method to control the response time of the C 12 A 7 -based accelerator to retain the workability of fresh concrete. It was found that the workability of the granulated C 12 A 7 -based accelerator was retained for the operation time after mixing, and adequate strength was developed to prevent early frost damage.

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“…Today, a variety of novel chemical admixtures can be added to shotcrete to improve strength, adhesiveness, cohesiveness, freezing/thawing and abrasion resistence characteristics and to reduce rebound [8][9][10][11][12][13][14].…”

Section: The Use Of Chemical Admixturesmentioning

confidence: 99%

Advancements in shotcrete technology

Bernardo

Guida

Mecca

2015

WIT Transactions on the Built Environment

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Shotcrete is a cement-based mixture pneumatically projected at high velocity onto a receiving surface. The material component of shotcrete is essentially concrete or sometimes mortar, but the process of shotcrete application is unique. This process allows a good compaction of concrete to be obtained without vibration. Compared to cast-in-place concrete, other important advantages of the shotcrete process are related to the reduction of the amount and time for formwork installation, removal, and associated labor costs, the very flexible logistics, very good working safety and good environmental conditions. Nowadays, because of the significant advances that occurred mainly in the last few decades, shotcrete can be considered a proper repair material particularly suitable in different situations such as where formwork is not practical or can be reduced or eliminated, where access to the work area is difficult, where thin layers and/or variable thickness is required and where normal casting techniques cannot be employed. This paper describes the two different application techniques of shotcrete, namely the dry-mix process and the wet-mix process, and discusses their respective advantages and disadvantages. The drawbacks of conventional shotcrete (only based on cement and aggregate mixtures) are reviewed and high performance shotcrete are presented. These novel shotcrete materials are produced through the addition of new generations of chemical admixtures, supplementary cementitious materials and reinforcement fibres. Cases histories of a successful use of the shotcrete process in the rehabilitations of architecturally important historic buildings are described.

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Influence of a C12A7 mineral-based accelerator on the strength and durability of shotcrete

Cited by 74 publications

References 6 publications

The Influence of Mayenite Employed as a Functional Component on Hydration Properties of Ordinary Portland Cement

The Influence of Mayenite Employed as a Functional Component on Hydration Properties of Ordinary Portland Cement

Control of response time of early-stage concrete with accelerator using granulation processing

Advancements in shotcrete technology

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